original_kernel/mm
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
..
Kconfig
Kconfig.debug
Makefile
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
kmemcheck.c
kmemleak-test.c
kmemleak.c
ksm.c
maccess.c
madvise.c
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 mm: mempolicy: Convert shared_policy mutex to spinlock 2013-01-02 17:32:13 -08:00
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 mm: fix zone_watermark_ok_safe() accounting of isolated pages 2013-01-04 16:11:46 -08:00
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 mempolicy: remove arg from mpol_parse_str, mpol_to_str 2013-01-02 09:27:10 -08:00
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 MM: vmscan: remove __devinit attribute. 2013-01-03 15:57:13 -08:00
vmstat.c