Mel Gorman 8fb74b9fb2 mm: compaction: partially revert capture of suitable high-order page ... Eric Wong reported on 3.7 and 3.8-rc2 that ppoll() got stuck when waiting for POLLIN on a local TCP socket. It was easier to trigger if there was disk IO and dirty pages at the same time and he bisected it to commit 1fb3f8ca0e ("mm: compaction: capture a suitable high-order page immediately when it is made available"). The intention of that patch was to improve high-order allocations under memory pressure after changes made to reclaim in 3.6 drastically hurt THP allocations but the approach was flawed. For Eric, the problem was that page->pfmemalloc was not being cleared for captured pages leading to a poor interaction with swap-over-NFS support causing the packets to be dropped. However, I identified a few more problems with the patch including the fact that it can increase contention on zone->lock in some cases which could result in async direct compaction being aborted early. In retrospect the capture patch took the wrong approach. What it should have done is mark the pageblock being migrated as MIGRATE_ISOLATE if it was allocating for THP and avoided races that way. While the patch was showing to improve allocation success rates at the time, the benefit is marginal given the relative complexity and it should be revisited from scratch in the context of the other reclaim-related changes that have taken place since the patch was first written and tested. This patch partially reverts commit 1fb3f8ca0e ("mm: compaction: capture a suitable high-order page immediately when it is made available"). Reported-and-tested-by: Eric Wong <normalperson@yhbt.net> Tested-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2013-01-11 14:54:56 -08:00
..
backing-dev.c
balloon_compaction.c
bootmem.c	mm: bootmem: fix free_all_bootmem_core() with odd bitmap alignment	2013-01-11 14:54:55 -08:00
bounce.c
cleancache.c
compaction.c	mm: compaction: partially revert capture of suitable high-order page	2013-01-11 14:54:56 -08:00
debug-pagealloc.c
dmapool.c
fadvise.c
failslab.c
filemap.c
filemap_xip.c
fremap.c
frontswap.c
highmem.c
huge_memory.c	mm: thp: acquire the anon_vma rwsem for write during split	2013-01-11 14:54:55 -08:00
hugetlb.c
hugetlb_cgroup.c
hwpoison-inject.c
init-mm.c
internal.h	mm: compaction: partially revert capture of suitable high-order page	2013-01-11 14:54:56 -08:00
interval_tree.c
Kconfig
Kconfig.debug
kmemcheck.c
kmemleak-test.c
kmemleak.c
ksm.c
maccess.c
madvise.c
Makefile
memblock.c	mm: memblock: fix wrong memmove size in memblock_merge_regions()	2013-01-11 14:54:54 -08:00
memcontrol.c
memory-failure.c
memory.c	mm: reinstante dropped pmd_trans_splitting() check	2013-01-09 08:36:54 -08:00
memory_hotplug.c
mempolicy.c
mempool.c
migrate.c	mm: migrate: check page_count of THP before migrating	2013-01-11 14:54:54 -08:00
mincore.c
mlock.c
mm_init.c
mmap.c	mm: mmap: annotate vm_lock_anon_vma locking properly for lockdep	2013-01-11 14:54:55 -08:00
mmu_context.c
mmu_notifier.c
mmzone.c
mprotect.c
mremap.c
msync.c
nobootmem.c
nommu.c
oom_kill.c
page-writeback.c
page_alloc.c	mm: compaction: partially revert capture of suitable high-order page	2013-01-11 14:54:56 -08:00
page_cgroup.c
page_io.c
page_isolation.c
pagewalk.c
percpu-km.c
percpu-vm.c
percpu.c
pgtable-generic.c
process_vm_access.c
quicklist.c
readahead.c
rmap.c
shmem.c
slab.c
slab.h
slab_common.c
slob.c
slub.c
sparse-vmemmap.c
sparse.c
swap.c
swap_state.c
swapfile.c
truncate.c
util.c
vmalloc.c
vmscan.c
vmstat.c