[RFCv2 0/3] free reclaimed pages by paging out instantly

Minchan Kim
2014-06-20T06:48:46Z

Normally, I/O completed pages for reclaim would be rotated into
inactive LRU tail without freeing. The why it works is we can't free
page from atomic context(ie, end_page_writeback) due to vaious locks
isn't aware of atomic context.

So for reclaiming the I/O completed pages, we need one more iteration
of reclaim and it could make unnecessary aging as well as CPU overhead.

Long time ago, at the first trial, most concern was memcg locking
but recently, Johnannes tried amazing effort to make memcg lock simple[1]
so I coded up this again based on his patchset.(Kudos to Johannes)

[1] mm: memcontrol: naturalize charge lifetime v3
https://lkml.org/lkml/2014/6/18/631

So, this patchset should go after [1] but not bad timing to prove
that how [1] make mm simple so that we can go further like this.

On 1G, 12 CPU kvm guest, build kernel 5 times and result.

Most of field isn't changed too much but one thing I can notice is
allocstall and pgrotated.
We could save direct reclaim 50% and page rotation 96%.
Yay!

Welcome testing, review and any feedback!

git clone -b mm/mm/asap_reclaim-v1r3 --single-branch git://git.kernel.org/pub/scm/linux/kernel/git/minchan/linux.git

TITLE OLD NEW DIFF (RATIO)
nr_free_pages -79,600 -85,018 -5,418 (106.81)
nr_alloc_batch -532 64 596 (-12.24)
nr_inactive_anon 1,601 1,913 312 (119.48)
nr_active_anon -66,021 -64,913 1,108 (98.32)
nr_inactive_file 25,921 29,974 4,053 (115.64)
nr_active_file 112,575 112,604 29 (100.03)
nr_unevictable 0 0 0 (100.00)
nr_mlock 0 0 0 (100.00)
nr_anon_pages -63,698 -62,601 1,097 (98.28)
nr_mapped -31,818 -32,657 -839 (102.64)
nr_file_pages 139,336 143,684 4,348 (103.12)
nr_dirty 9,741 9,332 -409 (95.80)
nr_writeback 0 0 0 (100.00)
nr_slab_reclaimable 3,453 2,969 -484 (85.99)
nr_slab_unreclaimable 1,348 1,503 155 (111.49)
nr_page_table_pages 303 169 -134 (55.92)
nr_kernel_stack 5 18 13 (316.67)
nr_unstable 0 0 0 (100.00)
nr_bounce 0 0 0 (100.00)
nr_vmscan_write 2,347,178 2,475,802 128,624 (105.48)
nr_vmscan_immediate_reclaim 21,292 18,863 -2,429 (88.59)
nr_writeback_temp 0 0 0 (100.00)
nr_isolated_anon 0 0 0 (100.00)
nr_isolated_file 0 0 0 (100.00)
nr_shmem -940 -940 0 (100.00)
nr_dirtied 9,059,820 9,055,880 -3,940 (99.96)
nr_written 10,721,761 10,875,384 153,623 (101.43)
numa_hit 667,598,890 667,289,491 -309,399 (99.95)
numa_miss 0 0 0 (100.00)
numa_foreign 0 0 0 (100.00)
numa_interleave 0 0 0 (100.00)
numa_local 667,598,890 667,289,491 -309,399 (99.95)
numa_other 0 0 0 (100.00)
workingset_refault 6,843,535 6,953,675 110,140 (101.61)
workingset_activate 500,648 462,529 -38,119 (92.39)
workingset_nodereclaim 13,696 12,420 -1,276 (90.68)
nr_anon_transparent_hugepages 0 0 0 (100.00)
nr_free_cma 0 0 0 (100.00)
nr_dirty_threshold 5,890 5,756 -134 (97.73)
nr_dirty_background_threshold 2,945 2,878 -67 (97.73)
pgpgin 40,253,436 40,048,188 -205,248 (99.49)
pgpgout 43,348,244 43,949,700 601,456 (101.39)
pswpin 1,341,538 1,341,174 -364 (99.97)
pswpout 2,238,838 2,401,758 162,920 (107.28)
pgalloc_dma 8,107,785 8,658,979 551,194 (106.80)
pgalloc_dma32 662,079,225 661,199,629 -879,596 (99.87)
pgalloc_normal 0 0 0 (100.00)
pgalloc_movable 0 0 0 (100.00)
pgfree 670,107,583 669,774,227 -333,356 (99.95)
pgactivate 6,644,334 6,643,232 -1,102 (99.98)
pgdeactivate 12,717,804 12,591,803 -126,001 (99.01)
pgfault 720,714,051 720,522,028 -192,023 (99.97)
pgmajfault 293,791 300,790 6,999 (102.38)
pgrefill_dma 339,536 357,065 17,529 (105.16)
pgrefill_dma32 13,042,608 12,882,276 -160,332 (98.77)
pgrefill_normal 0 0 0 (100.00)
pgrefill_movable 0 0 0 (100.00)
pgsteal_kswapd_dma 176,437 182,289 5,852 (103.32)
pgsteal_kswapd_dma32 17,820,059 15,877,438 -1,942,621 (89.10)
pgsteal_kswapd_normal 0 0 0 (100.00)
pgsteal_kswapd_movable 0 0 0 (100.00)
pgsteal_direct_dma 30 63 33 (206.45)
pgsteal_direct_dma32 388,468 208,411 -180,057 (53.65)
pgsteal_direct_normal 0 0 0 (100.00)
pgsteal_direct_movable 0 0 0 (100.00)
pgscan_kswapd_dma 190,486 199,076 8,590 (104.51)
pgscan_kswapd_dma32 22,002,203 20,034,956 -1,967,247 (91.06)
pgscan_kswapd_normal 0 0 0 (100.00)
pgscan_kswapd_movable 0 0 0 (100.00)
pgscan_direct_dma 45 175 130 (382.61)
pgscan_direct_dma32 722,765 714,866 -7,899 (98.91)
pgscan_direct_normal 0 0 0 (100.00)
pgscan_direct_movable 0 0 0 (100.00)
pgscan_direct_throttle 0 0 0 (100.00)
zone_reclaim_failed 0 0 0 (100.00)
pginodesteal 0 0 0 (100.00)
slabs_scanned 3,537,255 3,580,408 43,153 (101.22)
kswapd_inodesteal 374 0 -374 (0.27)
kswapd_low_wmark_hit_quickly 2,485 2,528 43 (101.73)
kswapd_high_wmark_hit_quickly 1,078 728 -350 (67.56)
pageoutrun 4,652 4,346 -306 (93.42)
allocstall 8,312 4,524 -3,788 (54.43)
pgrotated 2,205,712 86,860 -2,118,852 (3.94)
drop_pagecache 0 0 0 (100.00)
drop_slab 0 0 0 (100.00)
pgmigrate_success 0 0 0 (100.00)
pgmigrate_fail 0 0 0 (100.00)
compact_migrate_scanned 0 0 0 (100.00)
compact_free_scanned 0 0 0 (100.00)
compact_isolated 0 0 0 (100.00)
compact_stall 7 6 -1 (87.50)
compact_fail 7 6 -1 (87.50)
compact_success 0 0 0 (100.00)
htlb_buddy_alloc_success 0 0 0 (100.00)
htlb_buddy_alloc_fail 0 0 0 (100.00)
unevictable_pgs_culled 0 0 0 (100.00)
unevictable_pgs_scanned 0 0 0 (100.00)
unevictable_pgs_rescued 0 0 0 (100.00)
unevictable_pgs_mlocked 0 0 0 (100.00)
unevictable_pgs_munlocked 0 0 0 (100.00)
unevictable_pgs_cleared 0 0 0 (100.00)
unevictable_pgs_stranded 0 0 0 (100.00)
thp_fault_alloc 0 0 0 (100.00)
thp_fault_fallback 0 0 0 (100.00)
thp_collapse_alloc 0 0 0 (100.00)
thp_collapse_alloc_failed 0 0 0 (100.00)
thp_split 0 0 0 (100.00)
thp_zero_page_alloc 0 0 0 (100.00)
thp_zero_page_alloc_failed 0 0 0 (100.00)

Minchan Kim (3):
mm: Don't hide spin_lock in swap_info_get internal
mm: Introduce atomic_remove_mapping
mm: Free reclaimed pages indepdent of next reclaim

include/linux/swap.h | 4 ++++
mm/filemap.c | 17 +++++++++-----
mm/swap.c | 21 ++++++++++++++++++
mm/swapfile.c | 17 ++++++++++++--
mm/vmscan.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 114 insertions(+), 8 deletions(-)

--
2.0.0