Vlastimil Babka fdd4c6149a mm, vmscan: make compaction_ready() more accurate and readable ... The compaction_ready() is used during direct reclaim for costly order allocations to skip reclaim for zones where compaction should be attempted instead. It's combining the standard compaction_suitable() check with its own watermark check based on high watermark with extra gap, and the result is confusing at best. This patch attempts to better structure and document the checks involved. First, compaction_suitable() can determine that the allocation should either succeed already, or that compaction doesn't have enough free pages to proceed. The third possibility is that compaction has enough free pages, but we still decide to reclaim first - unless we are already above the high watermark with gap. This does not mean that the reclaim will actually reach this watermark during single attempt, this is rather an over-reclaim protection. So document the code as such. The check for compaction_deferred() is removed completely, as it in fact had no proper role here. The result after this patch is mainly a less confusing code. We also skip some over-reclaim in cases where the allocation should already succed. Link: http://lkml.kernel.org/r/20160810091226.6709-12-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Lorenzo Stoakes <lstoakes@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2016-10-07 18:46:27 -07:00
..
kasan	kasan: remove the unnecessary WARN_ONCE from quarantine.c	2016-08-11 16:58:14 -07:00
backing-dev.c	block: fix bdi vs gendisk lifetime mismatch	2016-08-04 14:19:16 -06:00
balloon_compaction.c	mm: balloon: use general non-lru movable page feature	2016-07-26 16:19:19 -07:00
bootmem.c
cleancache.c
cma.c	mm/cma: silence warnings due to max() usage	2016-05-27 14:49:37 -07:00
cma.h
cma_debug.c
compaction.c	mm, compaction: require only min watermarks for non-costly orders	2016-10-07 18:46:27 -07:00
debug.c	mm: avoid endless recursion in dump_page()	2016-09-19 15:36:16 -07:00
debug_page_ref.c
dmapool.c
early_ioremap.c
fadvise.c	mm/fadvise.c: do not discard partial pages with POSIX_FADV_DONTNEED	2016-06-09 14:23:11 -07:00
failslab.c
filemap.c	xfs: updates for 4.9-rc1	2016-10-06 08:18:10 -07:00
frame_vector.c
frontswap.c	mm, frontswap: convert frontswap_enabled to static key	2016-07-26 16:19:19 -07:00
gup.c	- ARM: GICv3 ITS emulation and various fixes. Removal of the old	2016-08-02 16:11:27 -04:00
highmem.c	mm/highmem: make nr_free_highpages() handles all highmem zones by itself	2016-05-19 19:12:14 -07:00
huge_memory.c	Merge branch 'linus' into sched/core, to pick up fixes	2016-09-30 10:44:27 +02:00
hugetlb.c	mm/hugetlb: fix incorrect hugepages count during mem hotplug	2016-08-11 16:58:13 -07:00
hugetlb_cgroup.c	mm, hugetlb_cgroup: round limit_in_bytes down to hugepage size	2016-05-20 17:58:30 -07:00
hwpoison-inject.c
init-mm.c
internal.h	mm, compaction: make whole_zone flag ignore cached scanner positions	2016-10-07 18:46:27 -07:00
interval_tree.c
Kconfig	mm: clarify COMPACTION Kconfig text	2016-08-26 17:39:35 -07:00
Kconfig.debug	PM / Hibernate: allow hibernation with PAGE_POISONING_ZERO	2016-09-13 02:35:27 +02:00
khugepaged.c	mm, thp: fix leaking mapped pte in __collapse_huge_page_swapin()	2016-09-19 15:36:16 -07:00
kmemcheck.c
kmemleak-test.c
kmemleak.c	kmemleak: don't hang if user disables scanning early	2016-07-28 16:07:41 -07:00
ksm.c	mm,ksm: fix endless looping in allocating memory when ksm enable	2016-09-28 16:19:01 -07:00
list_lru.c
maccess.c	x86: remove more uaccess_32.h complexity	2016-05-22 17:21:27 -07:00
madvise.c	mm: make mmap_sem for write waits killable for mm syscalls	2016-05-23 17:04:14 -07:00
Makefile	Implements HARDENED_USERCOPY verification of copy_to_user/copy_from_user	2016-08-08 14:48:14 -07:00
memblock.c	mm/memblock.c: fix NULL dereference error	2016-08-04 20:02:09 -04:00
memcontrol.c	mm: memcontrol: add sanity checks for memcg->id.ref on get/put	2016-10-07 18:46:26 -07:00
memory-failure.c	mm: hwpoison: remove incorrect comments	2016-07-28 16:07:41 -07:00
memory.c	Merge branch 'linus' into sched/core, to pick up fixes	2016-09-30 10:44:27 +02:00
memory_hotplug.c	mem-hotplug: use nodes that contain memory as mask in new_node_page()	2016-09-28 16:19:02 -07:00
mempolicy.c	mm, mempolicy: task->mempolicy must be NULL before dropping final reference	2016-09-01 17:52:01 -07:00
mempool.c	Revert "mm, mempool: only set __GFP_NOMEMALLOC if there are free elements"	2016-07-28 16:07:41 -07:00
memtest.c
migrate.c	mm, thp: remove __GFP_NORETRY from khugepaged and madvised allocations	2016-07-28 16:07:41 -07:00
mincore.c	mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage	2016-04-04 10:41:08 -07:00
mlock.c	mm, vmscan: move LRU lists to node	2016-07-28 16:07:41 -07:00
mm_init.c
mmap.c	Merge branch 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2016-10-03 17:29:01 -07:00
mmu_context.c	mm/mmu_context, sched/core: Fix mmu_context.h assumption	2016-04-28 11:44:19 +02:00
mmu_notifier.c	fix Christoph's email addresses	2016-03-17 15:09:34 -07:00
mmzone.c	mm, page_alloc: inline the fast path of the zonelist iterator	2016-05-19 19:12:14 -07:00
mprotect.c	mm: thp: check pmd_trans_unstable() after split_huge_pmd()	2016-07-26 16:19:19 -07:00
mremap.c	mm: thp: check pmd_trans_unstable() after split_huge_pmd()	2016-07-26 16:19:19 -07:00
msync.c
nobootmem.c
nommu.c	mm: introduce fault_env	2016-07-26 16:19:19 -07:00
oom_kill.c	mm/oom_kill.c: fix task_will_free_mem() comment	2016-10-07 18:46:26 -07:00
page-writeback.c	mm/writeback: Convert to hotplug state machine	2016-09-06 18:30:20 +02:00
page_alloc.c	mm, compaction: require only min watermarks for non-costly orders	2016-10-07 18:46:27 -07:00
page_counter.c
page_ext.c	mm: use early_pfn_to_nid in page_ext_init	2016-05-27 14:49:37 -07:00
page_idle.c	mm, vmscan: move lru_lock to the node	2016-07-28 16:07:41 -07:00
page_io.c	mm: fix the page_swap_info() BUG_ON check	2016-09-19 15:36:17 -07:00
page_isolation.c	mm/page_isolation: clean up confused code	2016-07-26 16:19:19 -07:00
page_owner.c	mm/page_owner: use stackdepot to store stacktrace	2016-07-26 16:19:19 -07:00
page_poison.c	mm: check the return value of lookup_page_ext for all call sites	2016-06-03 15:06:22 -07:00
pagewalk.c
percpu-km.c	mm: percpu: use pr_fmt to prefix output	2016-03-17 15:09:34 -07:00
percpu-vm.c
percpu.c	percpu: fix synchronization between synchronous map extension and chunk destruction	2016-05-25 11:48:25 -04:00
pgtable-generic.c
process_vm_access.c
quicklist.c	fix Christoph's email addresses	2016-03-17 15:09:34 -07:00
readahead.c	mm: silently skip readahead for DAX inodes	2016-08-26 17:39:35 -07:00
rmap.c	rmap: fix compound check logic in page_remove_file_rmap	2016-08-10 16:40:56 -07:00
shmem.c	huge tmpfs: fix Committed_AS leak	2016-09-24 11:20:01 -07:00
slab.c	slab: Convert to hotplug state machine	2016-09-06 18:30:20 +02:00
slab.h	mm, kasan: switch SLUB to stackdepot, enable memory quarantine for SLUB	2016-07-28 16:07:41 -07:00
slab_common.c	mm: charge/uncharge kmemcg from generic page allocator paths	2016-07-26 16:19:19 -07:00
slob.c
slub.c	slub: Convert to hotplug state machine	2016-09-06 18:30:20 +02:00
sparse-vmemmap.c	treewide: replace obsolete _refok by __ref	2016-08-02 17:31:41 -04:00
sparse.c	treewide: replace obsolete _refok by __ref	2016-08-02 17:31:41 -04:00
swap.c	mm, pagevec: release/reacquire lru_lock on pgdat change	2016-07-28 16:07:41 -07:00
swap_cgroup.c
swap_state.c	mm: move most file-based accounting to the node	2016-07-28 16:07:41 -07:00
swapfile.c	mm: fix the page_swap_info() BUG_ON check	2016-09-19 15:36:17 -07:00
truncate.c	truncate: handle file thp	2016-07-26 16:19:19 -07:00
usercopy.c	mm: usercopy: Check for module addresses	2016-09-20 16:07:39 -07:00
userfaultfd.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00
util.c	mm: move most file-based accounting to the node	2016-07-28 16:07:41 -07:00
vmacache.c
vmalloc.c	mm/vmalloc.c: fix align value calculation error	2016-10-07 18:46:26 -07:00
vmpressure.c
vmscan.c	mm, vmscan: make compaction_ready() more accurate and readable	2016-10-07 18:46:27 -07:00
vmstat.c	mm: remove reclaim and compaction retry approximations	2016-07-28 16:07:41 -07:00
workingset.c	mm: workingset: fix crash in shadow node shrinker caused by replace_page_cache_page()	2016-09-30 15:26:52 -07:00
z3fold.c	mm/z3fold.c: avoid modifying HEADLESS page and minor cleanup	2016-06-03 16:02:55 -07:00
zbud.c
zpool.c
zsmalloc.c	zsmalloc: Delete an unnecessary check before the function call "iput"	2016-07-28 16:07:41 -07:00
zswap.c	mm/zswap: use workqueue to destroy pool	2016-05-20 17:58:30 -07:00