Hugh Dickins 6f5e6b9e69 [PATCH] fix free swap cache latency ... Lee Revell reported 28ms latency when process with lots of swapped memory exits. 2.6.15 introduced a latency regression when unmapping: in accounting the zap_work latency breaker, pte_none counted 1, pte_present PAGE_SIZE, but a swap entry counted nothing at all. We think of pages present as the slow case, but Lee's trace shows that free_swap_and_cache's radix tree lookup can make a lot of work - and we could have been doing it many thousands of times without a latency break. Move the zap_work update up to account swap entries like pages present. This does account non-linear pte_file entries, and unmap_mapping_range skipping over swap entries, by the same amount even though they're quick: but neither of those cases deserves complicating the code (and they're treated no worse than they were in 2.6.14). Signed-off-by: Hugh Dickins <hugh@veritas.com> Acked-by: Nick Piggin <npiggin@suse.de> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>		2006-03-17 07:51:26 -08:00
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bootmem.c
fadvise.c
filemap_xip.c
filemap.c
filemap.h
fremap.c
highmem.c
hugetlb.c
internal.h
Kconfig
madvise.c
Makefile
memory_hotplug.c
memory.c	[PATCH] fix free swap cache latency	2006-03-17 07:51:26 -08:00
mempolicy.c
mempool.c
mincore.c
mlock.c
mmap.c
mprotect.c
mremap.c
msync.c
nommu.c
oom_kill.c
page_alloc.c
page_io.c
page-writeback.c
pdflush.c
prio_tree.c
readahead.c
rmap.c
shmem.c
slab.c
slob.c
sparse.c
swap_state.c
swap.c
swapfile.c
thrash.c
tiny-shmem.c
truncate.c
util.c
vmalloc.c
vmscan.c