commit 24b7e5819ad5cbef2b7c7376510862aa8319d240 upstream.
This was formerly the series "Improve sequential read throughput" which
noted some major differences in performance of tiobench since 3.0.
While there are a number of factors, two that dominated were the
introduction of the fair zone allocation policy and changes to CFQ.
The behaviour of fair zone allocation policy makes more sense than
tiobench as a benchmark and CFQ defaults were not changed due to
insufficient benchmarking.
This series is what's left. It's one functional fix to the fair zone
allocation policy when used on NUMA machines and a reduction of overhead
in general. tiobench was used for the comparison despite its flaws as
an IO benchmark as in this case we are primarily interested in the
overhead of page allocator and page reclaim activity.
On UMA, it makes little difference to overhead
3.16.0-rc3 3.16.0-rc3
vanilla lowercost-v5
User 383.61 386.77
System 403.83 401.74
Elapsed 5411.50 5413.11
On a 4-socket NUMA machine it's a bit more noticable
3.16.0-rc3 3.16.0-rc3
vanilla lowercost-v5
User 746.94 802.00
System 65336.22 40852.33
Elapsed 27553.52 27368.46
This patch (of 6):
The LRU insertion and activate tracepoints take PFN as a parameter
forcing the overhead to the caller. Move the overhead to the tracepoint
fast-assign method to ensure the cost is only incurred when the
tracepoint is active.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
commit f8c9301fa5a2a8b873c67f2a3d8230d5c13f61b7 upstream. During compaction, update_nr_listpages() has been used to count remaining non-migrated and free pages after a call to migrage_pages(). The freepages counting has become unneccessary, and it turns out that migratepages counting is also unnecessary in most cases. The only situation when it's needed to count cc->migratepages is when migrate_pages() returns with a negative error code. Otherwise, the non-negative return value is the number of pages that were not migrated, which is exactly the count of remaining pages in the cc->migratepages list. Furthermore, any non-zero count is only interesting for the tracepoint of mm_compaction_migratepages events, because after that all remaining unmigrated pages are put back and their count is set to 0. This patch therefore removes update_nr_listpages() completely, and changes the tracepoint definition so that the manual counting is done only when the tracepoint is enabled, and only when migrate_pages() returns a negative error code. Furthermore, migrate_pages() and the tracepoints won't be called when there's nothing to migrate. This potentially avoids some wasted cycles and reduces the volume of uninteresting mm_compaction_migratepages events where "nr_migrated=0 nr_failed=0". In the stress-highalloc mmtest, this was about 75% of the events. The mm_compaction_isolate_migratepages event is better for determining that nothing was isolated for migration, and this one was just duplicating the info. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Acked-by: Michal Nazarewicz <mina86@mina86.com> Cc: Christoph Lameter <cl@linux.com> Cc: Rik van Riel <riel@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
commit 0eb927c0ab789d3d7d69f68acb850f69d4e7c36f upstream.
The broad goal of the series is to improve allocation success rates for
huge pages through memory compaction, while trying not to increase the
compaction overhead. The original objective was to reintroduce
capturing of high-order pages freed by the compaction, before they are
split by concurrent activity. However, several bugs and opportunities
for simple improvements were found in the current implementation, mostly
through extra tracepoints (which are however too ugly for now to be
considered for sending).
The patches mostly deal with two mechanisms that reduce compaction
overhead, which is caching the progress of migrate and free scanners,
and marking pageblocks where isolation failed to be skipped during
further scans.
Patch 1 (from mgorman) adds tracepoints that allow calculate time spent in
compaction and potentially debug scanner pfn values.
Patch 2 encapsulates the some functionality for handling deferred compactions
for better maintainability, without a functional change
type is not determined without being actually needed.
Patch 3 fixes a bug where cached scanner pfn's are sometimes reset only after
they have been read to initialize a compaction run.
Patch 4 fixes a bug where scanners meeting is sometimes not properly detected
and can lead to multiple compaction attempts quitting early without
doing any work.
Patch 5 improves the chances of sync compaction to process pageblocks that
async compaction has skipped due to being !MIGRATE_MOVABLE.
Patch 6 improves the chances of sync direct compaction to actually do anything
when called after async compaction fails during allocation slowpath.
The impact of patches were validated using mmtests's stress-highalloc
benchmark with mmtests's stress-highalloc benchmark on a x86_64 machine
with 4GB memory.
Due to instability of the results (mostly related to the bugs fixed by
patches 2 and 3), 10 iterations were performed, taking min,mean,max
values for success rates and mean values for time and vmstat-based
metrics.
First, the default GFP_HIGHUSER_MOVABLE allocations were tested with the
patches stacked on top of v3.13-rc2. Patch 2 is OK to serve as baseline
due to no functional changes in 1 and 2. Comments below.
stress-highalloc
3.13-rc2 3.13-rc2 3.13-rc2 3.13-rc2 3.13-rc2
2-nothp 3-nothp 4-nothp 5-nothp 6-nothp
Success 1 Min 9.00 ( 0.00%) 10.00 (-11.11%) 43.00 (-377.78%) 43.00 (-377.78%) 33.00 (-266.67%)
Success 1 Mean 27.50 ( 0.00%) 25.30 ( 8.00%) 45.50 (-65.45%) 45.90 (-66.91%) 46.30 (-68.36%)
Success 1 Max 36.00 ( 0.00%) 36.00 ( 0.00%) 47.00 (-30.56%) 48.00 (-33.33%) 52.00 (-44.44%)
Success 2 Min 10.00 ( 0.00%) 8.00 ( 20.00%) 46.00 (-360.00%) 45.00 (-350.00%) 35.00 (-250.00%)
Success 2 Mean 26.40 ( 0.00%) 23.50 ( 10.98%) 47.30 (-79.17%) 47.60 (-80.30%) 48.10 (-82.20%)
Success 2 Max 34.00 ( 0.00%) 33.00 ( 2.94%) 48.00 (-41.18%) 50.00 (-47.06%) 54.00 (-58.82%)
Success 3 Min 65.00 ( 0.00%) 63.00 ( 3.08%) 85.00 (-30.77%) 84.00 (-29.23%) 85.00 (-30.77%)
Success 3 Mean 76.70 ( 0.00%) 70.50 ( 8.08%) 86.20 (-12.39%) 85.50 (-11.47%) 86.00 (-12.13%)
Success 3 Max 87.00 ( 0.00%) 86.00 ( 1.15%) 88.00 ( -1.15%) 87.00 ( 0.00%) 87.00 ( 0.00%)
3.13-rc2 3.13-rc2 3.13-rc2 3.13-rc2 3.13-rc2
2-nothp 3-nothp 4-nothp 5-nothp 6-nothp
User 6437.72 6459.76 5960.32 5974.55 6019.67
System 1049.65 1049.09 1029.32 1031.47 1032.31
Elapsed 1856.77 1874.48 1949.97 1994.22 1983.15
3.13-rc2 3.13-rc2 3.13-rc2 3.13-rc2 3.13-rc2
2-nothp 3-nothp 4-nothp 5-nothp 6-nothp
Minor Faults 253952267 254581900 250030122 250507333 250157829
Major Faults 420 407 506 530 530
Swap Ins 4 9 9 6 6
Swap Outs 398 375 345 346 333
Direct pages scanned 197538 189017 298574 287019 299063
Kswapd pages scanned 1809843 1801308 1846674 1873184 1861089
Kswapd pages reclaimed 1806972 1798684 1844219 1870509 1858622
Direct pages reclaimed 197227 188829 298380 286822 298835
Kswapd efficiency 99% 99% 99% 99% 99%
Kswapd velocity 953.382 970.449 952.243 934.569 922.286
Direct efficiency 99% 99% 99% 99% 99%
Direct velocity 104.058 101.832 153.961 143.200 148.205
Percentage direct scans 9% 9% 13% 13% 13%
Zone normal velocity 347.289 359.676 348.063 339.933 332.983
Zone dma32 velocity 710.151 712.605 758.140 737.835 737.507
Zone dma velocity 0.000 0.000 0.000 0.000 0.000
Page writes by reclaim 557.600 429.000 353.600 426.400 381.800
Page writes file 159 53 7 79 48
Page writes anon 398 375 345 346 333
Page reclaim immediate 825 644 411 575 420
Sector Reads 2781750 2769780 2878547 2939128 2910483
Sector Writes 12080843 12083351 12012892 12002132 12010745
Page rescued immediate 0 0 0 0 0
Slabs scanned 1575654 1545344 1778406 1786700 1794073
Direct inode steals 9657 10037 15795 14104 14645
Kswapd inode steals 46857 46335 50543 50716 51796
Kswapd skipped wait 0 0 0 0 0
THP fault alloc 97 91 81 71 77
THP collapse alloc 456 506 546 544 565
THP splits 6 5 5 4 4
THP fault fallback 0 1 0 0 0
THP collapse fail 14 14 12 13 12
Compaction stalls 1006 980 1537 1536 1548
Compaction success 303 284 562 559 578
Compaction failures 702 696 974 976 969
Page migrate success 1177325 1070077 3927538 3781870 3877057
Page migrate failure 0 0 0 0 0
Compaction pages isolated 2547248 2306457 8301218 8008500 8200674
Compaction migrate scanned 42290478 38832618 153961130 154143900 159141197
Compaction free scanned 89199429 79189151 356529027 351943166 356326727
Compaction cost 1566 1426 5312 5156 5294
NUMA PTE updates 0 0 0 0 0
NUMA hint faults 0 0 0 0 0
NUMA hint local faults 0 0 0 0 0
NUMA hint local percent 100 100 100 100 100
NUMA pages migrated 0 0 0 0 0
AutoNUMA cost 0 0 0 0 0
Observations:
- The "Success 3" line is allocation success rate with system idle
(phases 1 and 2 are with background interference). I used to get stable
values around 85% with vanilla 3.11. The lower min and mean values came
with 3.12. This was bisected to commit 81c0a2bb ("mm: page_alloc: fair
zone allocator policy") As explained in comment for patch 3, I don't
think the commit is wrong, but that it makes the effect of compaction
bugs worse. From patch 3 onwards, the results are OK and match the 3.11
results.
- Patch 4 also clearly helps phases 1 and 2, and exceeds any results
I've seen with 3.11 (I didn't measure it that thoroughly then, but it
was never above 40%).
- Compaction cost and number of scanned pages is higher, especially due
to patch 4. However, keep in mind that patches 3 and 4 fix existing
bugs in the current design of compaction overhead mitigation, they do
not change it. If overhead is found unacceptable, then it should be
decreased differently (and consistently, not due to random conditions)
than the current implementation does. In contrast, patches 5 and 6
(which are not strictly bug fixes) do not increase the overhead (but
also not success rates). This might be a limitation of the
stress-highalloc benchmark as it's quite uniform.
Another set of results is when configuring stress-highalloc t allocate
with similar flags as THP uses:
(GFP_HIGHUSER_MOVABLE|__GFP_NOMEMALLOC|__GFP_NORETRY|__GFP_NO_KSWAPD)
stress-highalloc
3.13-rc2 3.13-rc2 3.13-rc2 3.13-rc2 3.13-rc2
2-thp 3-thp 4-thp 5-thp 6-thp
Success 1 Min 2.00 ( 0.00%) 7.00 (-250.00%) 18.00 (-800.00%) 19.00 (-850.00%) 26.00 (-1200.00%)
Success 1 Mean 19.20 ( 0.00%) 17.80 ( 7.29%) 29.20 (-52.08%) 29.90 (-55.73%) 32.80 (-70.83%)
Success 1 Max 27.00 ( 0.00%) 29.00 ( -7.41%) 35.00 (-29.63%) 36.00 (-33.33%) 37.00 (-37.04%)
Success 2 Min 3.00 ( 0.00%) 8.00 (-166.67%) 21.00 (-600.00%) 21.00 (-600.00%) 32.00 (-966.67%)
Success 2 Mean 19.30 ( 0.00%) 17.90 ( 7.25%) 32.20 (-66.84%) 32.60 (-68.91%) 35.70 (-84.97%)
Success 2 Max 27.00 ( 0.00%) 30.00 (-11.11%) 36.00 (-33.33%) 37.00 (-37.04%) 39.00 (-44.44%)
Success 3 Min 62.00 ( 0.00%) 62.00 ( 0.00%) 85.00 (-37.10%) 75.00 (-20.97%) 64.00 ( -3.23%)
Success 3 Mean 66.30 ( 0.00%) 65.50 ( 1.21%) 85.60 (-29.11%) 83.40 (-25.79%) 83.50 (-25.94%)
Success 3 Max 70.00 ( 0.00%) 69.00 ( 1.43%) 87.00 (-24.29%) 86.00 (-22.86%) 87.00 (-24.29%)
3.13-rc2 3.13-rc2 3.13-rc2 3.13-rc2 3.13-rc2
2-thp 3-thp 4-thp 5-thp 6-thp
User 6547.93 6475.85 6265.54 6289.46 6189.96
System 1053.42 1047.28 1043.23 1042.73 1038.73
Elapsed 1835.43 1821.96 1908.67 1912.74 1956.38
3.13-rc2 3.13-rc2 3.13-rc2 3.13-rc2 3.13-rc2
2-thp 3-thp 4-thp 5-thp 6-thp
Minor Faults 256805673 253106328 253222299 249830289 251184418
Major Faults 395 375 423 434 448
Swap Ins 12 10 10 12 9
Swap Outs 530 537 487 455 415
Direct pages scanned 71859 86046 153244 152764 190713
Kswapd pages scanned 1900994 1870240 1898012 1892864 1880520
Kswapd pages reclaimed 1897814 1867428 1894939 1890125 1877924
Direct pages reclaimed 71766 85908 153167 152643 190600
Kswapd efficiency 99% 99% 99% 99% 99%
Kswapd velocity 1029.000 1067.782 1000.091 991.049 951.218
Direct efficiency 99% 99% 99% 99% 99%
Direct velocity 38.897 49.127 80.747 79.983 96.468
Percentage direct scans 3% 4% 7% 7% 9%
Zone normal velocity 351.377 372.494 348.910 341.689 335.310
Zone dma32 velocity 716.520 744.414 731.928 729.343 712.377
Zone dma velocity 0.000 0.000 0.000 0.000 0.000
Page writes by reclaim 669.300 604.000 545.700 538.900 429.900
Page writes file 138 66 58 83 14
Page writes anon 530 537 487 455 415
Page reclaim immediate 806 655 772 548 517
Sector Reads 2711956 2703239 2811602 2818248 2839459
Sector Writes 12163238 12018662 12038248 11954736 11994892
Page rescued immediate 0 0 0 0 0
Slabs scanned 1385088 1388364 1507968 1513292 1558656
Direct inode steals 1739 2564 4622 5496 6007
Kswapd inode steals 47461 46406 47804 48013 48466
Kswapd skipped wait 0 0 0 0 0
THP fault alloc 110 82 84 69 70
THP collapse alloc 445 482 467 462 539
THP splits 6 5 4 5 3
THP fault fallback 3 0 0 0 0
THP collapse fail 15 14 14 14 13
Compaction stalls 659 685 1033 1073 1111
Compaction success 222 225 410 427 456
Compaction failures 436 460 622 646 655
Page migrate success 446594 439978 1085640 1095062 1131716
Page migrate failure 0 0 0 0 0
Compaction pages isolated 1029475 1013490 2453074 2482698 2565400
Compaction migrate scanned 9955461 11344259 24375202 27978356 30494204
Compaction free scanned 27715272 28544654 80150615 82898631 85756132
Compaction cost 552 555 1344 1379 1436
NUMA PTE updates 0 0 0 0 0
NUMA hint faults 0 0 0 0 0
NUMA hint local faults 0 0 0 0 0
NUMA hint local percent 100 100 100 100 100
NUMA pages migrated 0 0 0 0 0
AutoNUMA cost 0 0 0 0 0
There are some differences from the previous results for THP-like allocations:
- Here, the bad result for unpatched kernel in phase 3 is much more
consistent to be between 65-70% and not related to the "regression" in
3.12. Still there is the improvement from patch 4 onwards, which brings
it on par with simple GFP_HIGHUSER_MOVABLE allocations.
- Compaction costs have increased, but nowhere near as much as the
non-THP case. Again, the patches should be worth the gained
determininsm.
- Patches 5 and 6 somewhat increase the number of migrate-scanned pages.
This is most likely due to __GFP_NO_KSWAPD flag, which means the cached
pfn's and pageblock skip bits are not reset by kswapd that often (at
least in phase 3 where no concurrent activity would wake up kswapd) and
the patches thus help the sync-after-async compaction. It doesn't
however show that the sync compaction would help so much with success
rates, which can be again seen as a limitation of the benchmark
scenario.
This patch (of 6):
Add two tracepoints for compaction begin and end of a zone. Using this it
is possible to calculate how much time a workload is spending within
compaction and potentially debug problems related to cached pfns for
scanning. In combination with the direct reclaim and slab trace points it
should be possible to estimate most allocation-related overhead for a
workload.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
commit 52c8f6a5aeb0bdd396849ecaa72d96f8175528f5 upstream. In general, every tracepoint should be zero overhead if it is disabled. However, trace_mm_page_alloc_extfrag() is one of exception. It evaluate "new_type == start_migratetype" even if tracepoint is disabled. However, the code can be moved into tracepoint's TP_fast_assign() and TP_fast_assign exist exactly such purpose. This patch does it. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
commit 098507ae3ec2331476fb52e85d4040c1cc6d0ef4 upstream. The replacement of the 'count' variable by two variables 'incs' and 'decs' to resolve some race conditions during module unloading was done in parallel with some cleanup in the trace subsystem, and was integrated as a merge. Unfortunately, the formula for this replacement was wrong in the tracing code, and the refcount in the traces was not usable as a result. Use 'count = incs - decs' to compute the user count. Link: http://lkml.kernel.org/p/1393924179-9147-1-git-send-email-romain.izard.pro@gmail.com Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Frederic Weisbecker <fweisbec@gmail.com> Fixes: c1ab9cab7509 "merge conflict resolution" Signed-off-by: Romain Izard <romain.izard.pro@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
commit af5040da01ef980670b3741b3e10733ee3e33566 upstream. trace_block_rq_complete does not take into account that request can be partially completed, so we can get the following incorrect output of blkparser: C R 232 + 240 [0] C R 240 + 232 [0] C R 248 + 224 [0] C R 256 + 216 [0] but should be: C R 232 + 8 [0] C R 240 + 8 [0] C R 248 + 8 [0] C R 256 + 8 [0] Also, the whole output summary statistics of completed requests and final throughput will be incorrect. This patch takes into account real completion size of the request and fixes wrong completion accounting. Signed-off-by: Roman Pen <r.peniaev@gmail.com> CC: Steven Rostedt <rostedt@goodmis.org> CC: Frederic Weisbecker <fweisbec@gmail.com> CC: Ingo Molnar <mingo@redhat.com> CC: linux-kernel@vger.kernel.org Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
The unpacked_lun field in the SCSI target tracepoints should be initialized with cmd->orig_fe_lun rather than cmd->se_lun->unpacked_lun for two reasons: - most importantly, if we are in the cmd_complete tracepoint returning a check condition due to no LUN found, cmd->se_lun will be NULL and we'll crash trying to dereference it. - also, in any case, cmd->se_lun->unpacked_lun is an internal index into the target's internal set of LUNs; cmd->orig_fe_lun is much more useful and interesting, since it's the value the initiator actually sent. Signed-off-by: Roland Dreier <roland@purestorage.com> Cc: <stable@vger.kernel.org> # 3.11+ Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Pull block IO fixes from Jens Axboe: "After merge window, no new stuff this time only a collection of neatly confined and simple fixes" * 'for-3.12/core' of git://git.kernel.dk/linux-block: cfq: explicitly use 64bit divide operation for 64bit arguments block: Add nr_bios to block_rq_remap tracepoint If the queue is dying then we only call the rq->end_io callout. This leaves bios setup on the request, because the caller assumes when the blk_execute_rq_nowait/blk_execute_rq call has completed that the rq->bios have been cleaned up. bio-integrity: Fix use of bs->bio_integrity_pool after free blkcg: relocate root_blkg setting and clearing block: Convert kmalloc_node(...GFP_ZERO...) to kzalloc_node(...) block: trace all devices plug operation
Pull btrfs fixes from Chris Mason: "These are mostly bug fixes and a two small performance fixes. The most important of the bunch are Josef's fix for a snapshotting regression and Mark's update to fix compile problems on arm" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (25 commits) Btrfs: create the uuid tree on remount rw btrfs: change extent-same to copy entire argument struct Btrfs: dir_inode_operations should use btrfs_update_time also btrfs: Add btrfs: prefix to kernel log output btrfs: refuse to remount read-write after abort Btrfs: btrfs_ioctl_default_subvol: Revert back to toplevel subvolume when arg is 0 Btrfs: don't leak transaction in btrfs_sync_file() Btrfs: add the missing mutex unlock in write_all_supers() Btrfs: iput inode on allocation failure Btrfs: remove space_info->reservation_progress Btrfs: kill delay_iput arg to the wait_ordered functions Btrfs: fix worst case calculator for space usage Revert "Btrfs: rework the overcommit logic to be based on the total size" Btrfs: improve replacing nocow extents Btrfs: drop dir i_size when adding new names on replay Btrfs: replay dir_index items before other items Btrfs: check roots last log commit when checking if an inode has been logged Btrfs: actually log directory we are fsync()'ing Btrfs: actually limit the size of delalloc range Btrfs: allocate the free space by the existed max extent size when ENOSPC ...
Adding the number of bios in a remapped request to 'block_rq_remap' tracepoint. Request remapper clones bios in a request to track the completion status of each bio. So the number of bios can be useful information for investigation. Related discussions: http://www.redhat.com/archives/dm-devel/2013-August/msg00084.html http://www.redhat.com/archives/dm-devel/2013-September/msg00024.html Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jens Axboe <axboe@kernel.dk>