commit c72efb658f7c8b27ca3d0efb5cfd5ded9fcac89e upstream.
From 1ebf33901ecc75d9496862dceb1ef0377980587c Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Mon, 23 Mar 2015 00:08:19 -0400
2f800fbd777b ("writeback: fix dirtied pages accounting on redirty")
introduced account_page_redirty() which reverts stat updates for a
redirtied page, making BDI_DIRTIED no longer monotonically increasing.
bdi_update_write_bandwidth() uses the delta in BDI_DIRTIED as the
basis for bandwidth calculation. While unlikely, since the above
patch, the newer value may be lower than the recorded past value and
underflow the bandwidth calculation leading to a wild result.
Fix it by subtracing min of the old and new values when calculating
delta. AFAIK, there hasn't been any report of it happening but the
resulting erratic behavior would be non-critical and temporary, so
it's possible that the issue is happening without being reported. The
risk of the fix is very low, so tagged for -stable.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Greg Thelen <gthelen@google.com>
Fixes: 2f800fbd777b ("writeback: fix dirtied pages accounting on redirty")
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7d70e15480c0450d2bfafaad338a32e884fc215e upstream.
global_update_bandwidth() uses static variable update_time as the
timestamp for the last update but forgets to initialize it to
INITIALIZE_JIFFIES.
This means that global_dirty_limit will be 5 mins into the future on
32bit and some large amount jiffies into the past on 64bit. This
isn't critical as the only effect is that global_dirty_limit won't be
updated for the first 5 mins after booting on 32bit machines,
especially given the auxiliary nature of global_dirty_limit's role -
protecting against global dirty threshold's sudden dips; however, it
does lead to unintended suboptimal behavior. Fix it.
Fixes: c42843f2f0bb ("writeback: introduce smoothed global dirty limit")
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b0dc3a342af36f95a68fe229b8f0f73552c5ca08 upstream.
Qiu Xishi reported the following BUG when testing hot-add/hot-remove node under
stress condition:
BUG: unable to handle kernel paging request at 0000000000025f60
IP: next_online_pgdat+0x1/0x50
PGD 0
Oops: 0000 [#1] SMP
ACPI: Device does not support D3cold
Modules linked in: fuse nls_iso8859_1 nls_cp437 vfat fat loop dm_mod coretemp mperf crc32c_intel ghash_clmulni_intel aesni_intel ablk_helper cryptd lrw gf128mul glue_helper aes_x86_64 pcspkr microcode igb dca i2c_algo_bit ipv6 megaraid_sas iTCO_wdt i2c_i801 i2c_core iTCO_vendor_support tg3 sg hwmon ptp lpc_ich pps_core mfd_core acpi_pad rtc_cmos button ext3 jbd mbcache sd_mod crc_t10dif scsi_dh_alua scsi_dh_rdac scsi_dh_hp_sw scsi_dh_emc scsi_dh ahci libahci libata scsi_mod [last unloaded: rasf]
CPU: 23 PID: 238 Comm: kworker/23:1 Tainted: G O 3.10.15-5885-euler0302 #1
Hardware name: HUAWEI TECHNOLOGIES CO.,LTD. Huawei N1/Huawei N1, BIOS V100R001 03/02/2015
Workqueue: events vmstat_update
task: ffffa800d32c0000 ti: ffffa800d32ae000 task.ti: ffffa800d32ae000
RIP: 0010: next_online_pgdat+0x1/0x50
RSP: 0018:ffffa800d32afce8 EFLAGS: 00010286
RAX: 0000000000001440 RBX: ffffffff81da53b8 RCX: 0000000000000082
RDX: 0000000000000000 RSI: 0000000000000082 RDI: 0000000000000000
RBP: ffffa800d32afd28 R08: ffffffff81c93bfc R09: ffffffff81cbdc96
R10: 00000000000040ec R11: 00000000000000a0 R12: ffffa800fffb3440
R13: ffffa800d32afd38 R14: 0000000000000017 R15: ffffa800e6616800
FS: 0000000000000000(0000) GS:ffffa800e6600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000025f60 CR3: 0000000001a0b000 CR4: 00000000001407e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
refresh_cpu_vm_stats+0xd0/0x140
vmstat_update+0x11/0x50
process_one_work+0x194/0x3d0
worker_thread+0x12b/0x410
kthread+0xc6/0xd0
ret_from_fork+0x7c/0xb0
The cause is the "memset(pgdat, 0, sizeof(*pgdat))" at the end of
try_offline_node, which will reset all the content of pgdat to 0, as the
pgdat is accessed lock-free, so that the users still using the pgdat
will panic, such as the vmstat_update routine.
process A: offline node XX:
vmstat_updat()
refresh_cpu_vm_stats()
for_each_populated_zone()
find online node XX
cond_resched()
offline cpu and memory, then try_offline_node()
node_set_offline(nid), and memset(pgdat, 0, sizeof(*pgdat))
zone = next_zone(zone)
pg_data_t *pgdat = zone->zone_pgdat; // here pgdat is NULL now
next_online_pgdat(pgdat)
next_online_node(pgdat->node_id); // NULL pointer access
So the solution here is postponing the reset of obsolete pgdat from
try_offline_node() to hotadd_new_pgdat(), and just resetting
pgdat->nr_zones and pgdat->classzone_idx to be 0 rather than the memset
0 to avoid breaking pointer information in pgdat.
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Reported-by: Xishi Qiu <qiuxishi@huawei.com>
Suggested-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9cb12d7b4ccaa976f97ce0c5fd0f1b6a83bc2a75 upstream.
For whatever reason, generic_access_phys() only remaps one page, but
actually allows to access arbitrary size. It's quite easy to trigger
large reads, like printing out large structure with gdb, which leads to a
crash. Fix it by remapping correct size.
Fixes: 28b2ee20c7cb ("access_process_vm device memory infrastructure")
Signed-off-by: Grazvydas Ignotas <notasas@gmail.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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 372549c2a3778fd3df445819811c944ad54609ca upstream.
What we want to check here is whether there is highorder freepage in buddy
list of other migratetype in order to steal it without fragmentation.
But, current code just checks cc->order which means allocation request
order. So, this is wrong.
Without this fix, non-movable synchronous compaction below pageblock order
would not stopped until compaction is complete, because migratetype of
most pageblocks are movable and high order freepage made by compaction is
usually on movable type buddy list.
There is some report related to this bug. See below link.
http://www.spinics.net/lists/linux-mm/msg81666.html
Although the issued system still has load spike comes from compaction,
this makes that system completely stable and responsive according to his
report.
stress-highalloc test in mmtests with non movable order 7 allocation
doesn't show any notable difference in allocation success rate, but, it
shows more compaction success rate.
Compaction success rate (Compaction success * 100 / Compaction stalls, %)
18.47 : 28.94
Fixes: 1fb3f8ca0e92 ("mm: compaction: capture a suitable high-order page immediately when it is made available")
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8138a67a5557ffea3a21dfd6f037842d4e748513 upstream.
I noticed that "allowed" can easily overflow by falling below 0, because
(total_vm / 32) can be larger than "allowed". The problem occurs in
OVERCOMMIT_NONE mode.
In this case, a huge allocation can success and overcommit the system
(despite OVERCOMMIT_NONE mode). All subsequent allocations will fall
(system-wide), so system become unusable.
The problem was masked out by commit c9b1d0981fcc
("mm: limit growth of 3% hardcoded other user reserve"),
but it's easy to reproduce it on older kernels:
1) set overcommit_memory sysctl to 2
2) mmap() large file multiple times (with VM_SHARED flag)
3) try to malloc() large amount of memory
It also can be reproduced on newer kernels, but miss-configured
sysctl_user_reserve_kbytes is required.
Fix this issue by switching to signed arithmetic here.
Signed-off-by: Roman Gushchin <klamm@yandex-team.ru>
Cc: Andrew Shewmaker <agshew@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5703b087dc8eaf47bfb399d6cf512d471beff405 upstream.
I noticed, that "allowed" can easily overflow by falling below 0,
because (total_vm / 32) can be larger than "allowed". The problem
occurs in OVERCOMMIT_NONE mode.
In this case, a huge allocation can success and overcommit the system
(despite OVERCOMMIT_NONE mode). All subsequent allocations will fall
(system-wide), so system become unusable.
The problem was masked out by commit c9b1d0981fcc
("mm: limit growth of 3% hardcoded other user reserve"),
but it's easy to reproduce it on older kernels:
1) set overcommit_memory sysctl to 2
2) mmap() large file multiple times (with VM_SHARED flag)
3) try to malloc() large amount of memory
It also can be reproduced on newer kernels, but miss-configured
sysctl_user_reserve_kbytes is required.
Fix this issue by switching to signed arithmetic here.
[akpm@linux-foundation.org: use min_t]
Signed-off-by: Roman Gushchin <klamm@yandex-team.ru>
Cc: Andrew Shewmaker <agshew@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 99592d598eca62bdbbf62b59941c189176dfc614 upstream.
When studying page stealing, I noticed some weird looking decisions in
try_to_steal_freepages(). The first I assume is a bug (Patch 1), the
following two patches were driven by evaluation.
Testing was done with stress-highalloc of mmtests, using the
mm_page_alloc_extfrag tracepoint and postprocessing to get counts of how
often page stealing occurs for individual migratetypes, and what
migratetypes are used for fallbacks. Arguably, the worst case of page
stealing is when UNMOVABLE allocation steals from MOVABLE pageblock.
RECLAIMABLE allocation stealing from MOVABLE allocation is also not ideal,
so the goal is to minimize these two cases.
The evaluation of v2 wasn't always clear win and Joonsoo questioned the
results. Here I used different baseline which includes RFC compaction
improvements from [1]. I found that the compaction improvements reduce
variability of stress-highalloc, so there's less noise in the data.
First, let's look at stress-highalloc configured to do sync compaction,
and how these patches reduce page stealing events during the test. First
column is after fresh reboot, other two are reiterations of test without
reboot. That was all accumulater over 5 re-iterations (so the benchmark
was run 5x3 times with 5 fresh restarts).
Baseline:
3.19-rc4 3.19-rc4 3.19-rc4
5-nothp-1 5-nothp-2 5-nothp-3
Page alloc extfrag event 10264225 8702233 10244125
Extfrag fragmenting 10263271 8701552 10243473
Extfrag fragmenting for unmovable 13595 17616 15960
Extfrag fragmenting unmovable placed with movable 7989 12193 8447
Extfrag fragmenting for reclaimable 658 1840 1817
Extfrag fragmenting reclaimable placed with movable 558 1677 1679
Extfrag fragmenting for movable 10249018 8682096 10225696
With Patch 1:
3.19-rc4 3.19-rc4 3.19-rc4
6-nothp-1 6-nothp-2 6-nothp-3
Page alloc extfrag event 11834954 9877523 9774860
Extfrag fragmenting 11833993 9876880 9774245
Extfrag fragmenting for unmovable 7342 16129 11712
Extfrag fragmenting unmovable placed with movable 4191 10547 6270
Extfrag fragmenting for reclaimable 373 1130 923
Extfrag fragmenting reclaimable placed with movable 302 906 738
Extfrag fragmenting for movable 11826278 9859621 9761610
With Patch 2:
3.19-rc4 3.19-rc4 3.19-rc4
7-nothp-1 7-nothp-2 7-nothp-3
Page alloc extfrag event 4725990 3668793 3807436
Extfrag fragmenting 4725104 3668252 3806898
Extfrag fragmenting for unmovable 6678 7974 7281
Extfrag fragmenting unmovable placed with movable 2051 3829 4017
Extfrag fragmenting for reclaimable 429 1208 1278
Extfrag fragmenting reclaimable placed with movable 369 976 1034
Extfrag fragmenting for movable 4717997 3659070 3798339
With Patch 3:
3.19-rc4 3.19-rc4 3.19-rc4
8-nothp-1 8-nothp-2 8-nothp-3
Page alloc extfrag event 5016183 4700142 3850633
Extfrag fragmenting 5015325 4699613 3850072
Extfrag fragmenting for unmovable 1312 3154 3088
Extfrag fragmenting unmovable placed with movable 1115 2777 2714
Extfrag fragmenting for reclaimable 437 1193 1097
Extfrag fragmenting reclaimable placed with movable 330 969 879
Extfrag fragmenting for movable 5013576 4695266 3845887
In v2 we've seen apparent regression with Patch 1 for unmovable events,
this is now gone, suggesting it was indeed noise. Here, each patch
improves the situation for unmovable events. Reclaimable is improved by
patch 1 and then either the same modulo noise, or perhaps sligtly worse -
a small price for unmovable improvements, IMHO. The number of movable
allocations falling back to other migratetypes is most noisy, but it's
reduced to half at Patch 2 nevertheless. These are least critical as
compaction can move them around.
If we look at success rates, the patches don't affect them, that didn't change.
Baseline:
3.19-rc4 3.19-rc4 3.19-rc4
5-nothp-1 5-nothp-2 5-nothp-3
Success 1 Min 49.00 ( 0.00%) 42.00 ( 14.29%) 41.00 ( 16.33%)
Success 1 Mean 51.00 ( 0.00%) 45.00 ( 11.76%) 42.60 ( 16.47%)
Success 1 Max 55.00 ( 0.00%) 51.00 ( 7.27%) 46.00 ( 16.36%)
Success 2 Min 53.00 ( 0.00%) 47.00 ( 11.32%) 44.00 ( 16.98%)
Success 2 Mean 59.60 ( 0.00%) 50.80 ( 14.77%) 48.20 ( 19.13%)
Success 2 Max 64.00 ( 0.00%) 56.00 ( 12.50%) 52.00 ( 18.75%)
Success 3 Min 84.00 ( 0.00%) 82.00 ( 2.38%) 78.00 ( 7.14%)
Success 3 Mean 85.60 ( 0.00%) 82.80 ( 3.27%) 79.40 ( 7.24%)
Success 3 Max 86.00 ( 0.00%) 83.00 ( 3.49%) 80.00 ( 6.98%)
Patch 1:
3.19-rc4 3.19-rc4 3.19-rc4
6-nothp-1 6-nothp-2 6-nothp-3
Success 1 Min 49.00 ( 0.00%) 44.00 ( 10.20%) 44.00 ( 10.20%)
Success 1 Mean 51.80 ( 0.00%) 46.00 ( 11.20%) 45.80 ( 11.58%)
Success 1 Max 54.00 ( 0.00%) 49.00 ( 9.26%) 49.00 ( 9.26%)
Success 2 Min 58.00 ( 0.00%) 49.00 ( 15.52%) 48.00 ( 17.24%)
Success 2 Mean 60.40 ( 0.00%) 51.80 ( 14.24%) 50.80 ( 15.89%)
Success 2 Max 63.00 ( 0.00%) 54.00 ( 14.29%) 55.00 ( 12.70%)
Success 3 Min 84.00 ( 0.00%) 81.00 ( 3.57%) 79.00 ( 5.95%)
Success 3 Mean 85.00 ( 0.00%) 81.60 ( 4.00%) 79.80 ( 6.12%)
Success 3 Max 86.00 ( 0.00%) 82.00 ( 4.65%) 82.00 ( 4.65%)
Patch 2:
3.19-rc4 3.19-rc4 3.19-rc4
7-nothp-1 7-nothp-2 7-nothp-3
Success 1 Min 50.00 ( 0.00%) 44.00 ( 12.00%) 39.00 ( 22.00%)
Success 1 Mean 52.80 ( 0.00%) 45.60 ( 13.64%) 42.40 ( 19.70%)
Success 1 Max 55.00 ( 0.00%) 46.00 ( 16.36%) 47.00 ( 14.55%)
Success 2 Min 52.00 ( 0.00%) 48.00 ( 7.69%) 45.00 ( 13.46%)
Success 2 Mean 53.40 ( 0.00%) 49.80 ( 6.74%) 48.80 ( 8.61%)
Success 2 Max 57.00 ( 0.00%) 52.00 ( 8.77%) 52.00 ( 8.77%)
Success 3 Min 84.00 ( 0.00%) 81.00 ( 3.57%) 79.00 ( 5.95%)
Success 3 Mean 85.00 ( 0.00%) 82.40 ( 3.06%) 79.60 ( 6.35%)
Success 3 Max 86.00 ( 0.00%) 83.00 ( 3.49%) 80.00 ( 6.98%)
Patch 3:
3.19-rc4 3.19-rc4 3.19-rc4
8-nothp-1 8-nothp-2 8-nothp-3
Success 1 Min 46.00 ( 0.00%) 44.00 ( 4.35%) 42.00 ( 8.70%)
Success 1 Mean 50.20 ( 0.00%) 45.60 ( 9.16%) 44.00 ( 12.35%)
Success 1 Max 52.00 ( 0.00%) 47.00 ( 9.62%) 47.00 ( 9.62%)
Success 2 Min 53.00 ( 0.00%) 49.00 ( 7.55%) 48.00 ( 9.43%)
Success 2 Mean 55.80 ( 0.00%) 50.60 ( 9.32%) 49.00 ( 12.19%)
Success 2 Max 59.00 ( 0.00%) 52.00 ( 11.86%) 51.00 ( 13.56%)
Success 3 Min 84.00 ( 0.00%) 80.00 ( 4.76%) 79.00 ( 5.95%)
Success 3 Mean 85.40 ( 0.00%) 81.60 ( 4.45%) 80.40 ( 5.85%)
Success 3 Max 87.00 ( 0.00%) 83.00 ( 4.60%) 82.00 ( 5.75%)
While there's no improvement here, I consider reduced fragmentation events
to be worth on its own. Patch 2 also seems to reduce scanning for free
pages, and migrations in compaction, suggesting it has somewhat less work
to do:
Patch 1:
Compaction stalls 4153 3959 3978
Compaction success 1523 1441 1446
Compaction failures 2630 2517 2531
Page migrate success 4600827 4943120 5104348
Page migrate failure 19763 16656 17806
Compaction pages isolated 9597640 10305617 10653541
Compaction migrate scanned 77828948 86533283 87137064
Compaction free scanned 517758295 521312840 521462251
Compaction cost 5503 5932 6110
Patch 2:
Compaction stalls 3800 3450 3518
Compaction success 1421 1316 1317
Compaction failures 2379 2134 2201
Page migrate success 4160421 4502708 4752148
Page migrate failure 19705 14340 14911
Compaction pages isolated 8731983 9382374 9910043
Compaction migrate scanned 98362797 96349194 98609686
Compaction free scanned 496512560 469502017 480442545
Compaction cost 5173 5526 5811
As with v2, /proc/pagetypeinfo appears unaffected with respect to numbers
of unmovable and reclaimable pageblocks.
Configuring the benchmark to allocate like THP page fault (i.e. no sync
compaction) gives much noisier results for iterations 2 and 3 after
reboot. This is not so surprising given how [1] offers lower improvements
in this scenario due to less restarts after deferred compaction which
would change compaction pivot.
Baseline:
3.19-rc4 3.19-rc4 3.19-rc4
5-thp-1 5-thp-2 5-thp-3
Page alloc extfrag event 8148965 6227815 6646741
Extfrag fragmenting 8147872 6227130 6646117
Extfrag fragmenting for unmovable 10324 12942 15975
Extfrag fragmenting unmovable placed with movable 5972 8495 10907
Extfrag fragmenting for reclaimable 601 1707 2210
Extfrag fragmenting reclaimable placed with movable 520 1570 2000
Extfrag fragmenting for movable 8136947 6212481 6627932
Patch 1:
3.19-rc4 3.19-rc4 3.19-rc4
6-thp-1 6-thp-2 6-thp-3
Page alloc extfrag event 8345457 7574471 7020419
Extfrag fragmenting 8343546 7573777 7019718
Extfrag fragmenting for unmovable 10256 18535 30716
Extfrag fragmenting unmovable placed with movable 6893 11726 22181
Extfrag fragmenting for reclaimable 465 1208 1023
Extfrag fragmenting reclaimable placed with movable 353 996 843
Extfrag fragmenting for movable 8332825 7554034 6987979
Patch 2:
3.19-rc4 3.19-rc4 3.19-rc4
7-thp-1 7-thp-2 7-thp-3
Page alloc extfrag event 3512847 3020756 2891625
Extfrag fragmenting 3511940 3020185 2891059
Extfrag fragmenting for unmovable 9017 6892 6191
Extfrag fragmenting unmovable placed with movable 1524 3053 2435
Extfrag fragmenting for reclaimable 445 1081 1160
Extfrag fragmenting reclaimable placed with movable 375 918 986
Extfrag fragmenting for movable 3502478 3012212 2883708
Patch 3:
3.19-rc4 3.19-rc4 3.19-rc4
8-thp-1 8-thp-2 8-thp-3
Page alloc extfrag event 3181699 3082881 2674164
Extfrag fragmenting 3180812 3082303 2673611
Extfrag fragmenting for unmovable 1201 4031 4040
Extfrag fragmenting unmovable placed with movable 974 3611 3645
Extfrag fragmenting for reclaimable 478 1165 1294
Extfrag fragmenting reclaimable placed with movable 387 985 1030
Extfrag fragmenting for movable 3179133 3077107 2668277
The improvements for first iteration are clear, the rest is much noisier
and can appear like regression for Patch 1. Anyway, patch 2 rectifies it.
Allocation success rates are again unaffected so there's no point in
making this e-mail any longer.
[1] http://marc.info/?l=linux-mm&m=142166196321125&w=2
This patch (of 3):
When __rmqueue_fallback() is called to allocate a page of order X, it will
find a page of order Y >= X of a fallback migratetype, which is different
from the desired migratetype. With the help of try_to_steal_freepages(),
it may change the migratetype (to the desired one) also of:
1) all currently free pages in the pageblock containing the fallback page
2) the fallback pageblock itself
3) buddy pages created by splitting the fallback page (when Y > X)
These decisions take the order Y into account, as well as the desired
migratetype, with the goal of preventing multiple fallback allocations
that could e.g. distribute UNMOVABLE allocations among multiple
pageblocks.
Originally, decision for 1) has implied the decision for 3). Commit
47118af076f6 ("mm: mmzone: MIGRATE_CMA migration type added") changed that
(probably unintentionally) so that the buddy pages in case 3) are always
changed to the desired migratetype, except for CMA pageblocks.
Commit fef903efcf0c ("mm/page_allo.c: restructure free-page stealing code
and fix a bug") did some refactoring and added a comment that the case of
3) is intended. Commit 0cbef29a7821 ("mm: __rmqueue_fallback() should
respect pageblock type") removed the comment and tried to restore the
original behavior where 1) implies 3), but due to the previous
refactoring, the result is instead that only 2) implies 3) - and the
conditions for 2) are less frequently met than conditions for 1). This
may increase fragmentation in situations where the code decides to steal
all free pages from the pageblock (case 1)), but then gives back the buddy
pages produced by splitting.
This patch restores the original intended logic where 1) implies 3).
During testing with stress-highalloc from mmtests, this has shown to
decrease the number of events where UNMOVABLE and RECLAIMABLE allocations
steal from MOVABLE pageblocks, which can lead to permanent fragmentation.
In some cases it has increased the number of events when MOVABLE
allocations steal from UNMOVABLE or RECLAIMABLE pageblocks, but these are
fixable by sync compaction and thus less harmful.
Note that evaluation has shown that the behavior introduced by
47118af076f6 for buddy pages in case 3) is actually even better than the
original logic, so the following patch will introduce it properly once
again. For stable backports of this patch it makes thus sense to only fix
versions containing 0cbef29a7821.
[iamjoonsoo.kim@lge.com: tracepoint fix]
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9fbc1f635fd0bd28cb32550211bf095753ac637a upstream.
If __unmap_hugepage_range() tries to unmap the address range over which
hugepage migration is on the way, we get the wrong page because pte_page()
doesn't work for migration entries. This patch simply clears the pte for
migration entries as we do for hwpoison entries.
Fixes: 290408d4a2 ("hugetlb: hugepage migration core")
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Steve Capper <steve.capper@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a8bda28d87c38c6aa93de28ba5d30cc18e865a11 upstream.
There is a race condition between hugepage migration and
change_protection(), where hugetlb_change_protection() doesn't care about
migration entries and wrongly overwrites them. That causes unexpected
results like kernel crash. HWPoison entries also can cause the same
problem.
This patch adds is_hugetlb_entry_(migration|hwpoisoned) check in this
function to do proper actions.
Fixes: 290408d4a2 ("hugetlb: hugepage migration core")
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Steve Capper <steve.capper@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>