linux/fs/xfs/kmem.c
Darrick J. Wong 08b005f133 xfs: remove kmem_zalloc_greedy
The sole remaining caller of kmem_zalloc_greedy is bulkstat, which uses
it to grab 1-4 pages for staging of inobt records.  The infinite loop in
the greedy allocation function is causing hangs[1] in generic/269, so
just get rid of the greedy allocator in favor of kmem_zalloc_large.
This makes bulkstat somewhat more likely to ENOMEM if there's really no
pages to spare, but eliminates a source of hangs.

[1] http://lkml.kernel.org/r/20170301044634.rgidgdqqiiwsmfpj%40XZHOUW.usersys.redhat.com

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
v2: remove single-page fallback
2017-03-07 20:10:50 -08:00

117 lines
3.2 KiB
C

/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <linux/mm.h>
#include <linux/sched/mm.h>
#include <linux/highmem.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include "kmem.h"
#include "xfs_message.h"
void *
kmem_alloc(size_t size, xfs_km_flags_t flags)
{
int retries = 0;
gfp_t lflags = kmem_flags_convert(flags);
void *ptr;
do {
ptr = kmalloc(size, lflags);
if (ptr || (flags & (KM_MAYFAIL|KM_NOSLEEP)))
return ptr;
if (!(++retries % 100))
xfs_err(NULL,
"%s(%u) possible memory allocation deadlock size %u in %s (mode:0x%x)",
current->comm, current->pid,
(unsigned int)size, __func__, lflags);
congestion_wait(BLK_RW_ASYNC, HZ/50);
} while (1);
}
void *
kmem_zalloc_large(size_t size, xfs_km_flags_t flags)
{
unsigned noio_flag = 0;
void *ptr;
gfp_t lflags;
ptr = kmem_zalloc(size, flags | KM_MAYFAIL);
if (ptr)
return ptr;
/*
* __vmalloc() will allocate data pages and auxillary structures (e.g.
* pagetables) with GFP_KERNEL, yet we may be under GFP_NOFS context
* here. Hence we need to tell memory reclaim that we are in such a
* context via PF_MEMALLOC_NOIO to prevent memory reclaim re-entering
* the filesystem here and potentially deadlocking.
*/
if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS))
noio_flag = memalloc_noio_save();
lflags = kmem_flags_convert(flags);
ptr = __vmalloc(size, lflags | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL);
if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS))
memalloc_noio_restore(noio_flag);
return ptr;
}
void *
kmem_realloc(const void *old, size_t newsize, xfs_km_flags_t flags)
{
int retries = 0;
gfp_t lflags = kmem_flags_convert(flags);
void *ptr;
do {
ptr = krealloc(old, newsize, lflags);
if (ptr || (flags & (KM_MAYFAIL|KM_NOSLEEP)))
return ptr;
if (!(++retries % 100))
xfs_err(NULL,
"%s(%u) possible memory allocation deadlock size %zu in %s (mode:0x%x)",
current->comm, current->pid,
newsize, __func__, lflags);
congestion_wait(BLK_RW_ASYNC, HZ/50);
} while (1);
}
void *
kmem_zone_alloc(kmem_zone_t *zone, xfs_km_flags_t flags)
{
int retries = 0;
gfp_t lflags = kmem_flags_convert(flags);
void *ptr;
do {
ptr = kmem_cache_alloc(zone, lflags);
if (ptr || (flags & (KM_MAYFAIL|KM_NOSLEEP)))
return ptr;
if (!(++retries % 100))
xfs_err(NULL,
"%s(%u) possible memory allocation deadlock in %s (mode:0x%x)",
current->comm, current->pid,
__func__, lflags);
congestion_wait(BLK_RW_ASYNC, HZ/50);
} while (1);
}