linux/mm/frontswap.c

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// SPDX-License-Identifier: GPL-2.0-only
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
/*
* Frontswap frontend
*
* This code provides the generic "frontend" layer to call a matching
* "backend" driver implementation of frontswap. See
* Documentation/mm/frontswap.rst for more information.
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
*
* Copyright (C) 2009-2012 Oracle Corp. All rights reserved.
* Author: Dan Magenheimer
*/
#include <linux/mman.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/security.h>
#include <linux/module.h>
#include <linux/debugfs.h>
#include <linux/frontswap.h>
#include <linux/swapfile.h>
mm, frontswap: convert frontswap_enabled to static key I have noticed that frontswap.h first declares "frontswap_enabled" as extern bool variable, and then overrides it with "#define frontswap_enabled (1)" for CONFIG_FRONTSWAP=Y or (0) when disabled. The bool variable isn't actually instantiated anywhere. This all looks like an unfinished attempt to make frontswap_enabled reflect whether a backend is instantiated. But in the current state, all frontswap hooks call unconditionally into frontswap.c just to check if frontswap_ops is non-NULL. This should at least be checked inline, but we can further eliminate the overhead when CONFIG_FRONTSWAP is enabled and no backend registered, using a static key that is initially disabled, and gets enabled only upon first backend registration. Thus, checks for "frontswap_enabled" are replaced with "frontswap_enabled()" wrapping the static key check. There are two exceptions: - xen's selfballoon_process() was testing frontswap_enabled in code guarded by #ifdef CONFIG_FRONTSWAP, which was effectively always true when reachable. The patch just removes this check. Using frontswap_enabled() does not sound correct here, as this can be true even without xen's own backend being registered. - in SYSCALL_DEFINE2(swapon), change the check to IS_ENABLED(CONFIG_FRONTSWAP) as it seems the bitmap allocation cannot currently be postponed until a backend is registered. This means that frontswap will still have some memory overhead by being configured, but without a backend. After the patch, we can expect that some functions in frontswap.c are called only when frontswap_ops is non-NULL. Change the checks there to VM_BUG_ONs. While at it, convert other BUG_ONs to VM_BUG_ONs as frontswap has been stable for some time. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/1463152235-9717-1-git-send-email-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26 22:24:42 +00:00
DEFINE_STATIC_KEY_FALSE(frontswap_enabled_key);
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
/*
* frontswap_ops are added by frontswap_register_ops, and provide the
* frontswap "backend" implementation functions. Multiple implementations
* may be registered, but implementations can never deregister. This
* is a simple singly-linked list of all registered implementations.
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
*/
static const struct frontswap_ops *frontswap_ops __read_mostly;
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
#ifdef CONFIG_DEBUG_FS
/*
* Counters available via /sys/kernel/debug/frontswap (if debugfs is
* properly configured). These are for information only so are not protected
* against increment races.
*/
static u64 frontswap_loads;
static u64 frontswap_succ_stores;
static u64 frontswap_failed_stores;
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
static u64 frontswap_invalidates;
mm/mempool: minor coding style tweaks Various coding style tweaks to various files under mm/ [daizhiyuan@phytium.com.cn: mm/swapfile: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614223624-16055-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/sparse: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614227288-19363-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/vmscan: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614227649-19853-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/compaction: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228218-20770-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/oom_kill: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228360-21168-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/shmem: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228504-21491-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/page_alloc: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228613-21754-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/filemap: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228936-22337-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/mlock: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613956588-2453-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/frontswap: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613962668-15045-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/vmalloc: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613963379-15988-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/memory_hotplug: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613971784-24878-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/mempolicy: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613972228-25501-1-git-send-email-daizhiyuan@phytium.com.cn Link: https://lkml.kernel.org/r/1614222374-13805-1-git-send-email-daizhiyuan@phytium.com.cn Signed-off-by: Zhiyuan Dai <daizhiyuan@phytium.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-05 01:40:12 +00:00
static inline void inc_frontswap_loads(void)
{
mm/frontswap: mark various intentional data races There are a few information counters that are intentionally not protected against increment races, so just annotate them using the data_race() macro. BUG: KCSAN: data-race in __frontswap_store / __frontswap_store write to 0xffffffff8b7174d8 of 8 bytes by task 6396 on cpu 103: __frontswap_store+0x2d0/0x344 inc_frontswap_failed_stores at mm/frontswap.c:70 (inlined by) __frontswap_store at mm/frontswap.c:280 swap_writepage+0x83/0xf0 pageout+0x33e/0xae0 shrink_page_list+0x1f57/0x2870 shrink_inactive_list+0x316/0x880 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x170/0x700 __handle_mm_fault+0xc9f/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 read to 0xffffffff8b7174d8 of 8 bytes by task 6405 on cpu 47: __frontswap_store+0x2b9/0x344 inc_frontswap_failed_stores at mm/frontswap.c:70 (inlined by) __frontswap_store at mm/frontswap.c:280 swap_writepage+0x83/0xf0 pageout+0x33e/0xae0 shrink_page_list+0x1f57/0x2870 shrink_inactive_list+0x316/0x880 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x170/0x700 __handle_mm_fault+0xc9f/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Marco Elver <elver@google.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Link: http://lkml.kernel.org/r/1581114499-5042-1-git-send-email-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-15 00:31:17 +00:00
data_race(frontswap_loads++);
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
}
mm/mempool: minor coding style tweaks Various coding style tweaks to various files under mm/ [daizhiyuan@phytium.com.cn: mm/swapfile: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614223624-16055-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/sparse: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614227288-19363-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/vmscan: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614227649-19853-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/compaction: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228218-20770-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/oom_kill: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228360-21168-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/shmem: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228504-21491-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/page_alloc: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228613-21754-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/filemap: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228936-22337-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/mlock: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613956588-2453-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/frontswap: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613962668-15045-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/vmalloc: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613963379-15988-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/memory_hotplug: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613971784-24878-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/mempolicy: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613972228-25501-1-git-send-email-daizhiyuan@phytium.com.cn Link: https://lkml.kernel.org/r/1614222374-13805-1-git-send-email-daizhiyuan@phytium.com.cn Signed-off-by: Zhiyuan Dai <daizhiyuan@phytium.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-05 01:40:12 +00:00
static inline void inc_frontswap_succ_stores(void)
{
mm/frontswap: mark various intentional data races There are a few information counters that are intentionally not protected against increment races, so just annotate them using the data_race() macro. BUG: KCSAN: data-race in __frontswap_store / __frontswap_store write to 0xffffffff8b7174d8 of 8 bytes by task 6396 on cpu 103: __frontswap_store+0x2d0/0x344 inc_frontswap_failed_stores at mm/frontswap.c:70 (inlined by) __frontswap_store at mm/frontswap.c:280 swap_writepage+0x83/0xf0 pageout+0x33e/0xae0 shrink_page_list+0x1f57/0x2870 shrink_inactive_list+0x316/0x880 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x170/0x700 __handle_mm_fault+0xc9f/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 read to 0xffffffff8b7174d8 of 8 bytes by task 6405 on cpu 47: __frontswap_store+0x2b9/0x344 inc_frontswap_failed_stores at mm/frontswap.c:70 (inlined by) __frontswap_store at mm/frontswap.c:280 swap_writepage+0x83/0xf0 pageout+0x33e/0xae0 shrink_page_list+0x1f57/0x2870 shrink_inactive_list+0x316/0x880 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x170/0x700 __handle_mm_fault+0xc9f/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Marco Elver <elver@google.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Link: http://lkml.kernel.org/r/1581114499-5042-1-git-send-email-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-15 00:31:17 +00:00
data_race(frontswap_succ_stores++);
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
}
mm/mempool: minor coding style tweaks Various coding style tweaks to various files under mm/ [daizhiyuan@phytium.com.cn: mm/swapfile: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614223624-16055-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/sparse: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614227288-19363-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/vmscan: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614227649-19853-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/compaction: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228218-20770-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/oom_kill: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228360-21168-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/shmem: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228504-21491-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/page_alloc: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228613-21754-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/filemap: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228936-22337-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/mlock: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613956588-2453-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/frontswap: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613962668-15045-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/vmalloc: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613963379-15988-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/memory_hotplug: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613971784-24878-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/mempolicy: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613972228-25501-1-git-send-email-daizhiyuan@phytium.com.cn Link: https://lkml.kernel.org/r/1614222374-13805-1-git-send-email-daizhiyuan@phytium.com.cn Signed-off-by: Zhiyuan Dai <daizhiyuan@phytium.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-05 01:40:12 +00:00
static inline void inc_frontswap_failed_stores(void)
{
mm/frontswap: mark various intentional data races There are a few information counters that are intentionally not protected against increment races, so just annotate them using the data_race() macro. BUG: KCSAN: data-race in __frontswap_store / __frontswap_store write to 0xffffffff8b7174d8 of 8 bytes by task 6396 on cpu 103: __frontswap_store+0x2d0/0x344 inc_frontswap_failed_stores at mm/frontswap.c:70 (inlined by) __frontswap_store at mm/frontswap.c:280 swap_writepage+0x83/0xf0 pageout+0x33e/0xae0 shrink_page_list+0x1f57/0x2870 shrink_inactive_list+0x316/0x880 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x170/0x700 __handle_mm_fault+0xc9f/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 read to 0xffffffff8b7174d8 of 8 bytes by task 6405 on cpu 47: __frontswap_store+0x2b9/0x344 inc_frontswap_failed_stores at mm/frontswap.c:70 (inlined by) __frontswap_store at mm/frontswap.c:280 swap_writepage+0x83/0xf0 pageout+0x33e/0xae0 shrink_page_list+0x1f57/0x2870 shrink_inactive_list+0x316/0x880 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x170/0x700 __handle_mm_fault+0xc9f/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Marco Elver <elver@google.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Link: http://lkml.kernel.org/r/1581114499-5042-1-git-send-email-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-15 00:31:17 +00:00
data_race(frontswap_failed_stores++);
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
}
mm/mempool: minor coding style tweaks Various coding style tweaks to various files under mm/ [daizhiyuan@phytium.com.cn: mm/swapfile: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614223624-16055-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/sparse: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614227288-19363-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/vmscan: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614227649-19853-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/compaction: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228218-20770-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/oom_kill: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228360-21168-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/shmem: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228504-21491-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/page_alloc: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228613-21754-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/filemap: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228936-22337-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/mlock: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613956588-2453-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/frontswap: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613962668-15045-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/vmalloc: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613963379-15988-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/memory_hotplug: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613971784-24878-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/mempolicy: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613972228-25501-1-git-send-email-daizhiyuan@phytium.com.cn Link: https://lkml.kernel.org/r/1614222374-13805-1-git-send-email-daizhiyuan@phytium.com.cn Signed-off-by: Zhiyuan Dai <daizhiyuan@phytium.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-05 01:40:12 +00:00
static inline void inc_frontswap_invalidates(void)
{
mm/frontswap: mark various intentional data races There are a few information counters that are intentionally not protected against increment races, so just annotate them using the data_race() macro. BUG: KCSAN: data-race in __frontswap_store / __frontswap_store write to 0xffffffff8b7174d8 of 8 bytes by task 6396 on cpu 103: __frontswap_store+0x2d0/0x344 inc_frontswap_failed_stores at mm/frontswap.c:70 (inlined by) __frontswap_store at mm/frontswap.c:280 swap_writepage+0x83/0xf0 pageout+0x33e/0xae0 shrink_page_list+0x1f57/0x2870 shrink_inactive_list+0x316/0x880 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x170/0x700 __handle_mm_fault+0xc9f/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 read to 0xffffffff8b7174d8 of 8 bytes by task 6405 on cpu 47: __frontswap_store+0x2b9/0x344 inc_frontswap_failed_stores at mm/frontswap.c:70 (inlined by) __frontswap_store at mm/frontswap.c:280 swap_writepage+0x83/0xf0 pageout+0x33e/0xae0 shrink_page_list+0x1f57/0x2870 shrink_inactive_list+0x316/0x880 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x170/0x700 __handle_mm_fault+0xc9f/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Marco Elver <elver@google.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Link: http://lkml.kernel.org/r/1581114499-5042-1-git-send-email-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-15 00:31:17 +00:00
data_race(frontswap_invalidates++);
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
}
#else
static inline void inc_frontswap_loads(void) { }
static inline void inc_frontswap_succ_stores(void) { }
static inline void inc_frontswap_failed_stores(void) { }
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
static inline void inc_frontswap_invalidates(void) { }
#endif
/*
* Due to the asynchronous nature of the backends loading potentially
* _after_ the swap system has been activated, we have chokepoints
* on all frontswap functions to not call the backend until the backend
* has registered.
*
* This would not guards us against the user deciding to call swapoff right as
* we are calling the backend to initialize (so swapon is in action).
* Fortunately for us, the swapon_mutex has been taken by the callee so we are
* OK. The other scenario where calls to frontswap_store (called via
* swap_writepage) is racing with frontswap_invalidate_area (called via
* swapoff) is again guarded by the swap subsystem.
*
* While no backend is registered all calls to frontswap_[store|load|
* invalidate_area|invalidate_page] are ignored or fail.
*
* The time between the backend being registered and the swap file system
* calling the backend (via the frontswap_* functions) is indeterminate as
* frontswap_ops is not atomic_t (or a value guarded by a spinlock).
* That is OK as we are comfortable missing some of these calls to the newly
* registered backend.
*
* Obviously the opposite (unloading the backend) must be done after all
* the frontswap_[store|load|invalidate_area|invalidate_page] start
* ignoring or failing the requests. However, there is currently no way
* to unload a backend once it is registered.
*/
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
/*
* Register operations for frontswap
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
*/
int frontswap_register_ops(const struct frontswap_ops *ops)
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
{
if (frontswap_ops)
return -EINVAL;
frontswap_ops = ops;
mm, frontswap: convert frontswap_enabled to static key I have noticed that frontswap.h first declares "frontswap_enabled" as extern bool variable, and then overrides it with "#define frontswap_enabled (1)" for CONFIG_FRONTSWAP=Y or (0) when disabled. The bool variable isn't actually instantiated anywhere. This all looks like an unfinished attempt to make frontswap_enabled reflect whether a backend is instantiated. But in the current state, all frontswap hooks call unconditionally into frontswap.c just to check if frontswap_ops is non-NULL. This should at least be checked inline, but we can further eliminate the overhead when CONFIG_FRONTSWAP is enabled and no backend registered, using a static key that is initially disabled, and gets enabled only upon first backend registration. Thus, checks for "frontswap_enabled" are replaced with "frontswap_enabled()" wrapping the static key check. There are two exceptions: - xen's selfballoon_process() was testing frontswap_enabled in code guarded by #ifdef CONFIG_FRONTSWAP, which was effectively always true when reachable. The patch just removes this check. Using frontswap_enabled() does not sound correct here, as this can be true even without xen's own backend being registered. - in SYSCALL_DEFINE2(swapon), change the check to IS_ENABLED(CONFIG_FRONTSWAP) as it seems the bitmap allocation cannot currently be postponed until a backend is registered. This means that frontswap will still have some memory overhead by being configured, but without a backend. After the patch, we can expect that some functions in frontswap.c are called only when frontswap_ops is non-NULL. Change the checks there to VM_BUG_ONs. While at it, convert other BUG_ONs to VM_BUG_ONs as frontswap has been stable for some time. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/1463152235-9717-1-git-send-email-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26 22:24:42 +00:00
static_branch_inc(&frontswap_enabled_key);
return 0;
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
}
/*
* Called when a swap device is swapon'd.
*/
void frontswap_init(unsigned type, unsigned long *map)
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
{
struct swap_info_struct *sis = swap_info[type];
mm, frontswap: convert frontswap_enabled to static key I have noticed that frontswap.h first declares "frontswap_enabled" as extern bool variable, and then overrides it with "#define frontswap_enabled (1)" for CONFIG_FRONTSWAP=Y or (0) when disabled. The bool variable isn't actually instantiated anywhere. This all looks like an unfinished attempt to make frontswap_enabled reflect whether a backend is instantiated. But in the current state, all frontswap hooks call unconditionally into frontswap.c just to check if frontswap_ops is non-NULL. This should at least be checked inline, but we can further eliminate the overhead when CONFIG_FRONTSWAP is enabled and no backend registered, using a static key that is initially disabled, and gets enabled only upon first backend registration. Thus, checks for "frontswap_enabled" are replaced with "frontswap_enabled()" wrapping the static key check. There are two exceptions: - xen's selfballoon_process() was testing frontswap_enabled in code guarded by #ifdef CONFIG_FRONTSWAP, which was effectively always true when reachable. The patch just removes this check. Using frontswap_enabled() does not sound correct here, as this can be true even without xen's own backend being registered. - in SYSCALL_DEFINE2(swapon), change the check to IS_ENABLED(CONFIG_FRONTSWAP) as it seems the bitmap allocation cannot currently be postponed until a backend is registered. This means that frontswap will still have some memory overhead by being configured, but without a backend. After the patch, we can expect that some functions in frontswap.c are called only when frontswap_ops is non-NULL. Change the checks there to VM_BUG_ONs. While at it, convert other BUG_ONs to VM_BUG_ONs as frontswap has been stable for some time. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/1463152235-9717-1-git-send-email-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26 22:24:42 +00:00
VM_BUG_ON(sis == NULL);
/*
* p->frontswap is a bitmap that we MUST have to figure out which page
* has gone in frontswap. Without it there is no point of continuing.
*/
if (WARN_ON(!map))
return;
/*
* Irregardless of whether the frontswap backend has been loaded
* before this function or it will be later, we _MUST_ have the
* p->frontswap set to something valid to work properly.
*/
frontswap_map_set(sis, map);
frontswap: don't call ->init if no ops are registered If no frontswap module (i.e. zswap) was registered, frontswap_ops will be NULL. In such situation, swapon crashes with the following stack trace: Unable to handle kernel access to user memory outside uaccess routines at virtual address 0000000000000000 Mem abort info: ESR = 0x0000000096000004 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x04: level 0 translation fault Data abort info: ISV = 0, ISS = 0x00000004 CM = 0, WnR = 0 user pgtable: 4k pages, 48-bit VAs, pgdp=00000020a4fab000 [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 Internal error: Oops: 96000004 [#1] SMP Modules linked in: zram fsl_dpaa2_eth pcs_lynx phylink ahci_qoriq crct10dif_ce ghash_ce sbsa_gwdt fsl_mc_dpio nvme lm90 nvme_core at803x xhci_plat_hcd rtc_fsl_ftm_alarm xgmac_mdio ahci_platform i2c_imx ip6_tables ip_tables fuse Unloaded tainted modules: cppc_cpufreq():1 CPU: 10 PID: 761 Comm: swapon Not tainted 6.0.0-rc2-00454-g22100432cf14 #1 Hardware name: SolidRun Ltd. SolidRun CEX7 Platform, BIOS EDK II Jun 21 2022 pstate: 00400005 (nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : frontswap_init+0x38/0x60 lr : __do_sys_swapon+0x8a8/0x9f4 sp : ffff80000969bcf0 x29: ffff80000969bcf0 x28: ffff37bee0d8fc00 x27: ffff80000a7f5000 x26: fffffcdefb971e80 x25: ffffaba797453b90 x24: 0000000000000064 x23: ffff37c1f209d1a8 x22: ffff37bee880e000 x21: ffffaba797748560 x20: ffff37bee0d8fce4 x19: ffffaba797748488 x18: 0000000000000014 x17: 0000000030ec029a x16: ffffaba795a479b0 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000030 x12: 0000000000000001 x11: ffff37c63c0aba18 x10: 0000000000000000 x9 : ffffaba7956b8c88 x8 : ffff80000969bcd0 x7 : 0000000000000000 x6 : 0000000000000000 x5 : 0000000000000001 x4 : 0000000000000000 x3 : ffffaba79730f000 x2 : ffff37bee0d8fc00 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: frontswap_init+0x38/0x60 __do_sys_swapon+0x8a8/0x9f4 __arm64_sys_swapon+0x28/0x3c invoke_syscall+0x78/0x100 el0_svc_common.constprop.0+0xd4/0xf4 do_el0_svc+0x38/0x4c el0_svc+0x34/0x10c el0t_64_sync_handler+0x11c/0x150 el0t_64_sync+0x190/0x194 Code: d000e283 910003fd f9006c41 f946d461 (f9400021) ---[ end trace 0000000000000000 ]--- Link: https://lkml.kernel.org/r/20220909130829.3262926-1-hch@lst.de Fixes: 1da0d94a3ec8 ("frontswap: remove support for multiple ops") Reported-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Liu Shixin <liushixin2@huawei.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-09 13:08:29 +00:00
if (!frontswap_enabled())
return;
frontswap_ops->init(type);
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
}
static bool __frontswap_test(struct swap_info_struct *sis,
pgoff_t offset)
{
if (sis->frontswap_map)
return test_bit(offset, sis->frontswap_map);
return false;
}
static inline void __frontswap_set(struct swap_info_struct *sis,
pgoff_t offset)
{
set_bit(offset, sis->frontswap_map);
atomic_inc(&sis->frontswap_pages);
}
static inline void __frontswap_clear(struct swap_info_struct *sis,
pgoff_t offset)
{
clear_bit(offset, sis->frontswap_map);
atomic_dec(&sis->frontswap_pages);
}
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
/*
* "Store" data from a page to frontswap and associate it with the page's
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
* swaptype and offset. Page must be locked and in the swap cache.
* If frontswap already contains a page with matching swaptype and
* offset, the frontswap implementation may either overwrite the data and
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
* return success or invalidate the page from frontswap and return failure.
*/
int __frontswap_store(struct page *page)
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
{
int ret = -1;
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
swp_entry_t entry = { .val = page_private(page), };
int type = swp_type(entry);
struct swap_info_struct *sis = swap_info[type];
pgoff_t offset = swp_offset(entry);
mm, frontswap: convert frontswap_enabled to static key I have noticed that frontswap.h first declares "frontswap_enabled" as extern bool variable, and then overrides it with "#define frontswap_enabled (1)" for CONFIG_FRONTSWAP=Y or (0) when disabled. The bool variable isn't actually instantiated anywhere. This all looks like an unfinished attempt to make frontswap_enabled reflect whether a backend is instantiated. But in the current state, all frontswap hooks call unconditionally into frontswap.c just to check if frontswap_ops is non-NULL. This should at least be checked inline, but we can further eliminate the overhead when CONFIG_FRONTSWAP is enabled and no backend registered, using a static key that is initially disabled, and gets enabled only upon first backend registration. Thus, checks for "frontswap_enabled" are replaced with "frontswap_enabled()" wrapping the static key check. There are two exceptions: - xen's selfballoon_process() was testing frontswap_enabled in code guarded by #ifdef CONFIG_FRONTSWAP, which was effectively always true when reachable. The patch just removes this check. Using frontswap_enabled() does not sound correct here, as this can be true even without xen's own backend being registered. - in SYSCALL_DEFINE2(swapon), change the check to IS_ENABLED(CONFIG_FRONTSWAP) as it seems the bitmap allocation cannot currently be postponed until a backend is registered. This means that frontswap will still have some memory overhead by being configured, but without a backend. After the patch, we can expect that some functions in frontswap.c are called only when frontswap_ops is non-NULL. Change the checks there to VM_BUG_ONs. While at it, convert other BUG_ONs to VM_BUG_ONs as frontswap has been stable for some time. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/1463152235-9717-1-git-send-email-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26 22:24:42 +00:00
VM_BUG_ON(!frontswap_ops);
VM_BUG_ON(!PageLocked(page));
VM_BUG_ON(sis == NULL);
/*
* If a dup, we must remove the old page first; we can't leave the
* old page no matter if the store of the new page succeeds or fails,
* and we can't rely on the new page replacing the old page as we may
* not store to the same implementation that contains the old page.
*/
if (__frontswap_test(sis, offset)) {
__frontswap_clear(sis, offset);
frontswap_ops->invalidate_page(type, offset);
}
ret = frontswap_ops->store(type, offset, page);
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
if (ret == 0) {
__frontswap_set(sis, offset);
inc_frontswap_succ_stores();
} else {
inc_frontswap_failed_stores();
}
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
return ret;
}
/*
* "Get" data from frontswap associated with swaptype and offset that were
* specified when the data was put to frontswap and use it to fill the
* specified page with data. Page must be locked and in the swap cache.
*/
int __frontswap_load(struct page *page)
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
{
int ret = -1;
swp_entry_t entry = { .val = page_private(page), };
int type = swp_type(entry);
struct swap_info_struct *sis = swap_info[type];
pgoff_t offset = swp_offset(entry);
mm, frontswap: convert frontswap_enabled to static key I have noticed that frontswap.h first declares "frontswap_enabled" as extern bool variable, and then overrides it with "#define frontswap_enabled (1)" for CONFIG_FRONTSWAP=Y or (0) when disabled. The bool variable isn't actually instantiated anywhere. This all looks like an unfinished attempt to make frontswap_enabled reflect whether a backend is instantiated. But in the current state, all frontswap hooks call unconditionally into frontswap.c just to check if frontswap_ops is non-NULL. This should at least be checked inline, but we can further eliminate the overhead when CONFIG_FRONTSWAP is enabled and no backend registered, using a static key that is initially disabled, and gets enabled only upon first backend registration. Thus, checks for "frontswap_enabled" are replaced with "frontswap_enabled()" wrapping the static key check. There are two exceptions: - xen's selfballoon_process() was testing frontswap_enabled in code guarded by #ifdef CONFIG_FRONTSWAP, which was effectively always true when reachable. The patch just removes this check. Using frontswap_enabled() does not sound correct here, as this can be true even without xen's own backend being registered. - in SYSCALL_DEFINE2(swapon), change the check to IS_ENABLED(CONFIG_FRONTSWAP) as it seems the bitmap allocation cannot currently be postponed until a backend is registered. This means that frontswap will still have some memory overhead by being configured, but without a backend. After the patch, we can expect that some functions in frontswap.c are called only when frontswap_ops is non-NULL. Change the checks there to VM_BUG_ONs. While at it, convert other BUG_ONs to VM_BUG_ONs as frontswap has been stable for some time. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/1463152235-9717-1-git-send-email-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26 22:24:42 +00:00
VM_BUG_ON(!frontswap_ops);
VM_BUG_ON(!PageLocked(page));
VM_BUG_ON(sis == NULL);
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
if (!__frontswap_test(sis, offset))
return -1;
/* Try loading from each implementation, until one succeeds. */
ret = frontswap_ops->load(type, offset, page);
if (ret == 0)
inc_frontswap_loads();
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
return ret;
}
/*
* Invalidate any data from frontswap associated with the specified swaptype
* and offset so that a subsequent "get" will fail.
*/
void __frontswap_invalidate_page(unsigned type, pgoff_t offset)
{
struct swap_info_struct *sis = swap_info[type];
mm, frontswap: convert frontswap_enabled to static key I have noticed that frontswap.h first declares "frontswap_enabled" as extern bool variable, and then overrides it with "#define frontswap_enabled (1)" for CONFIG_FRONTSWAP=Y or (0) when disabled. The bool variable isn't actually instantiated anywhere. This all looks like an unfinished attempt to make frontswap_enabled reflect whether a backend is instantiated. But in the current state, all frontswap hooks call unconditionally into frontswap.c just to check if frontswap_ops is non-NULL. This should at least be checked inline, but we can further eliminate the overhead when CONFIG_FRONTSWAP is enabled and no backend registered, using a static key that is initially disabled, and gets enabled only upon first backend registration. Thus, checks for "frontswap_enabled" are replaced with "frontswap_enabled()" wrapping the static key check. There are two exceptions: - xen's selfballoon_process() was testing frontswap_enabled in code guarded by #ifdef CONFIG_FRONTSWAP, which was effectively always true when reachable. The patch just removes this check. Using frontswap_enabled() does not sound correct here, as this can be true even without xen's own backend being registered. - in SYSCALL_DEFINE2(swapon), change the check to IS_ENABLED(CONFIG_FRONTSWAP) as it seems the bitmap allocation cannot currently be postponed until a backend is registered. This means that frontswap will still have some memory overhead by being configured, but without a backend. After the patch, we can expect that some functions in frontswap.c are called only when frontswap_ops is non-NULL. Change the checks there to VM_BUG_ONs. While at it, convert other BUG_ONs to VM_BUG_ONs as frontswap has been stable for some time. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/1463152235-9717-1-git-send-email-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26 22:24:42 +00:00
VM_BUG_ON(!frontswap_ops);
VM_BUG_ON(sis == NULL);
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
if (!__frontswap_test(sis, offset))
return;
frontswap_ops->invalidate_page(type, offset);
__frontswap_clear(sis, offset);
inc_frontswap_invalidates();
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
}
/*
* Invalidate all data from frontswap associated with all offsets for the
* specified swaptype.
*/
void __frontswap_invalidate_area(unsigned type)
{
struct swap_info_struct *sis = swap_info[type];
mm, frontswap: convert frontswap_enabled to static key I have noticed that frontswap.h first declares "frontswap_enabled" as extern bool variable, and then overrides it with "#define frontswap_enabled (1)" for CONFIG_FRONTSWAP=Y or (0) when disabled. The bool variable isn't actually instantiated anywhere. This all looks like an unfinished attempt to make frontswap_enabled reflect whether a backend is instantiated. But in the current state, all frontswap hooks call unconditionally into frontswap.c just to check if frontswap_ops is non-NULL. This should at least be checked inline, but we can further eliminate the overhead when CONFIG_FRONTSWAP is enabled and no backend registered, using a static key that is initially disabled, and gets enabled only upon first backend registration. Thus, checks for "frontswap_enabled" are replaced with "frontswap_enabled()" wrapping the static key check. There are two exceptions: - xen's selfballoon_process() was testing frontswap_enabled in code guarded by #ifdef CONFIG_FRONTSWAP, which was effectively always true when reachable. The patch just removes this check. Using frontswap_enabled() does not sound correct here, as this can be true even without xen's own backend being registered. - in SYSCALL_DEFINE2(swapon), change the check to IS_ENABLED(CONFIG_FRONTSWAP) as it seems the bitmap allocation cannot currently be postponed until a backend is registered. This means that frontswap will still have some memory overhead by being configured, but without a backend. After the patch, we can expect that some functions in frontswap.c are called only when frontswap_ops is non-NULL. Change the checks there to VM_BUG_ONs. While at it, convert other BUG_ONs to VM_BUG_ONs as frontswap has been stable for some time. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/1463152235-9717-1-git-send-email-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26 22:24:42 +00:00
VM_BUG_ON(!frontswap_ops);
VM_BUG_ON(sis == NULL);
if (sis->frontswap_map == NULL)
return;
frontswap_ops->invalidate_area(type);
atomic_set(&sis->frontswap_pages, 0);
bitmap_zero(sis->frontswap_map, sis->max);
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
}
static int __init init_frontswap(void)
{
#ifdef CONFIG_DEBUG_FS
struct dentry *root = debugfs_create_dir("frontswap", NULL);
if (root == NULL)
return -ENXIO;
debugfs_create_u64("loads", 0444, root, &frontswap_loads);
debugfs_create_u64("succ_stores", 0444, root, &frontswap_succ_stores);
debugfs_create_u64("failed_stores", 0444, root,
&frontswap_failed_stores);
debugfs_create_u64("invalidates", 0444, root, &frontswap_invalidates);
mm: frontswap: core frontswap functionality This patch, 3of4, provides the core frontswap code that interfaces between the hooks in the swap subsystem and a frontswap backend via frontswap_ops. --- New file added: mm/frontswap.c [v14: add support for writethrough, per suggestion by aarcange@redhat.com] [v11: sjenning@linux.vnet.ibm.com: s/puts/failed_puts/] [v10: sjenning@linux.vnet.ibm.com: fix debugfs calls on 32-bit] [v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 1] [v9: akpm@linux-foundation.org: mark some statics __read_mostly] [v9: akpm@linux-foundation.org: add clarifying comments] [v9: akpm@linux-foundation.org: no need to loop repeating try_to_unuse] [v9: error27@gmail.com: remove superfluous check for NULL] [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: add comment to clarify find_next_to_unuse] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: use new static inlines, no-ops if not config'd] [v6: rebase to 3.1-rc1] [v6: lliubbo@gmail.com: use vzalloc] [v6: lliubbo@gmail.com: fix null pointer deref if vzalloc fails] [v6: konrad.wilk@oracl.com: various checks and code clarifications/comments] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: Jan Beulich <JBeulich@novell.com> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chris Mason <chris.mason@oracle.com> Cc: Rik Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [v12: Squashed s/flush/invalidate/ in] [v15: A bit of cleanup and seperate DEBUGFS] Signed-off-by: Konrad Wilk <konrad.wilk@oracle.com>
2012-04-09 23:09:27 +00:00
#endif
return 0;
}
module_init(init_frontswap);