- 26 Sep, 2014 40 commits
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Vladimir Davydov authored
commit d5bc5fd3 upstream. The name `max_pass' is misleading, because this variable actually keeps the estimate number of freeable objects, not the maximal number of objects we can scan in this pass, which can be twice that. Rename it to reflect its actual meaning. Signed-off-by:
Vladimir Davydov <vdavydov@parallels.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>
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Vladimir Davydov authored
commit 99120b77 upstream. When direct reclaim is executed by a process bound to a set of NUMA nodes, we should scan only those nodes when possible, but currently we will scan kmem from all online nodes even if the kmem shrinker is NUMA aware. That said, binding a process to a particular NUMA node won't prevent it from shrinking inode/dentry caches from other nodes, which is not good. Fix this. Signed-off-by:
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Jens Axboe authored
commit 7fcbbaf1 upstream. In some testing I ran today (some fio jobs that spread over two nodes), we end up spending 40% of the time in filemap_check_errors(). That smells fishy. Looking further, this is basically what happens: blkdev_aio_read() generic_file_aio_read() filemap_write_and_wait_range() if (!mapping->nr_pages) filemap_check_errors() and filemap_check_errors() always attempts two test_and_clear_bit() on the mapping flags, thus dirtying it for every single invocation. The patch below tests each of these bits before clearing them, avoiding this issue. In my test case (4-socket box), performance went from 1.7M IOPS to 4.0M IOPS. Signed-off-by:
Jens Axboe <axboe@fb.com> Acked-by:
Jeff Moyer <jmoyer@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Mel Gorman authored
commit d26914d1 upstream. Since put_mems_allowed() is strictly optional, its a seqcount retry, we don't need to evaluate the function if the allocation was in fact successful, saving a smp_rmb some loads and comparisons on some relative fast-paths. Since the naming, get/put_mems_allowed() does suggest a mandatory pairing, rename the interface, as suggested by Mel, to resemble the seqcount interface. This gives us: read_mems_allowed_begin() and read_mems_allowed_retry(), where it is important to note that the return value of the latter call is inverted from its previous incarnation. Signed-off-by:
Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by:
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Raghavendra K T authored
commit 6d2be915 upstream. Currently max_sane_readahead() returns zero on the cpu whose NUMA node has no local memory which leads to readahead failure. Fix this readahead failure by returning minimum of (requested pages, 512). Users running applications on a memory-less cpu which needs readahead such as streaming application see considerable boost in the performance. Result: fadvise experiment with FADV_WILLNEED on a PPC machine having memoryless CPU with 1GB testfile (12 iterations) yielded around 46.66% improvement. fadvise experiment with FADV_WILLNEED on a x240 machine with 1GB testfile 32GB* 4G RAM numa machine (12 iterations) showed no impact on the normal NUMA cases w/ patch. Kernel Avg Stddev base 7.4975 3.92% patched 7.4174 3.26% [Andrew: making return value PAGE_SIZE independent] Suggested-by:
Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Acked-by:
Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by:
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David Rientjes authored
commit 91ca9186 upstream. The cached pageblock hint should be ignored when triggering compaction through /proc/sys/vm/compact_memory so all eligible memory is isolated. Manually invoking compaction is known to be expensive, there's no need to skip pageblocks based on heuristics (mainly for debugging). Signed-off-by:
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David Rientjes authored
commit da1c67a7 upstream. The conditions that control the isolation mode in isolate_migratepages_range() do not change during the iteration, so extract them out and only define the value once. This actually does have an effect, gcc doesn't optimize it itself because of cc->sync. Signed-off-by:
Rik van Riel <riel@redhat.com> Acked-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by:
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Joonsoo Kim authored
commit b6c75016 upstream. It is just for clean-up to reduce code size and improve readability. There is no functional change. Signed-off-by:
Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by:
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Joonsoo Kim authored
commit c122b208 upstream. isolation_suitable() and migrate_async_suitable() is used to be sure that this pageblock range is fine to be migragted. It isn't needed to call it on every page. Current code do well if not suitable, but, don't do well when suitable. 1) It re-checks isolation_suitable() on each page of a pageblock that was already estabilished as suitable. 2) It re-checks migrate_async_suitable() on each page of a pageblock that was not entered through the next_pageblock: label, because last_pageblock_nr is not otherwise updated. This patch fixes situation by 1) calling isolation_suitable() only once per pageblock and 2) always updating last_pageblock_nr to the pageblock that was just checked. Additionally, move PageBuddy() check after pageblock unit check, since pageblock check is the first thing we should do and makes things more simple. [vbabka@suse.cz: rephrase commit description] Signed-off-by:
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Joonsoo Kim authored
commit be1aa03b upstream. It is odd to drop the spinlock when we scan (SWAP_CLUSTER_MAX - 1) th pfn page. This may results in below situation while isolating migratepage. 1. try isolate 0x0 ~ 0x200 pfn pages. 2. When low_pfn is 0x1ff, ((low_pfn+1) % SWAP_CLUSTER_MAX) == 0, so drop the spinlock. 3. Then, to complete isolating, retry to aquire the lock. I think that it is better to use SWAP_CLUSTER_MAX th pfn for checking the criteria about dropping the lock. This has no harm 0x0 pfn, because, at this time, locked variable would be false. Signed-off-by:
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Joonsoo Kim authored
commit 01ead534 upstream. suitable_migration_target() checks that pageblock is suitable for migration target. In isolate_freepages_block(), it is called on every page and this is inefficient. So make it called once per pageblock. suitable_migration_target() also checks if page is highorder or not, but it's criteria for highorder is pageblock order. So calling it once within pageblock range has no problem. Signed-off-by:
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Joonsoo Kim authored
commit 7d348b9e upstream. Purpose of compaction is to get a high order page. Currently, if we find high-order page while searching migration target page, we break it to order-0 pages and use them as migration target. It is contrary to purpose of compaction, so disallow high-order page to be used for migration target. Additionally, clean-up logic in suitable_migration_target() to simplify the code. There is no functional changes from this clean-up. Signed-off-by:
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David Rientjes authored
commit 119d6d59 upstream. Page migration will fail for memory that is pinned in memory with, for example, get_user_pages(). In this case, it is unnecessary to take zone->lru_lock or isolating the page and passing it to page migration which will ultimately fail. This is a racy check, the page can still change from under us, but in that case we'll just fail later when attempting to move the page. This avoids very expensive memory compaction when faulting transparent hugepages after pinning a lot of memory with a Mellanox driver. On a 128GB machine and pinning ~120GB of memory, before this patch we see the enormous disparity in the number of page migration failures because of the pinning (from /proc/vmstat): compact_pages_moved 8450 compact_pagemigrate_failed 15614415 0.05% of pages isolated are successfully migrated and explicitly triggering memory compaction takes 102 seconds. After the patch: compact_pages_moved 9197 compact_pagemigrate_failed 7 99.9% of pages isolated are now successfully migrated in this configuration and memory compaction takes less than one second. Signed-off-by:
Hugh Dickins <hughd@google.com> Acked-by:
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Yasuaki Ishimatsu authored
commit 943dca1a upstream. Yasuaki Ishimatsu reported memory hot-add spent more than 5 _hours_ on 9TB memory machine since onlining memory sections is too slow. And we found out setup_zone_migrate_reserve spent >90% of the time. The problem is, setup_zone_migrate_reserve scans all pageblocks unconditionally, but it is only necessary if the number of reserved block was reduced (i.e. memory hot remove). Moreover, maximum MIGRATE_RESERVE per zone is currently 2. It means that the number of reserved pageblocks is almost always unchanged. This patch adds zone->nr_migrate_reserve_block to maintain the number of MIGRATE_RESERVE pageblocks and it reduces the overhead of setup_zone_migrate_reserve dramatically. The following table shows time of onlining a memory section. Amount of memory | 128GB | 192GB | 256GB| --------------------------------------------- linux-3.12 | 23.9 | 31.4 | 44.5 | This patch | 8.3 | 8.3 | 8.6 | Mel's proposal patch | 10.9 | 19.2 | 31.3 | --------------------------------------------- (millisecond) 128GB : 4 nodes and each node has 32GB of memory 192GB : 6 nodes and each node has 32GB of memory 256GB : 8 nodes and each node has 32GB of memory (*1) Mel proposed his idea by the following threads. https://lkml.org/lkml/2013/10/30/272 [akpm@linux-foundation.org: tweak comment] Signed-off-by:
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by:
Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Reported-by:
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Vladimir Davydov authored
commit ec97097b upstream. If a shrinker is not NUMA-aware, shrink_slab() should call it exactly once with nid=0, but currently it is not true: if node 0 is not set in the nodemask or if it is not online, we will not call such shrinkers at all. As a result some slabs will be left untouched under some circumstances. Let us fix it. Signed-off-by:
Dave Chinner <dchinner@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: Glauber Costa <glommer@gmail.com> Signed-off-by:
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Vladimir Davydov authored
commit 0b1fb40a upstream. When reclaiming kmem, we currently don't scan slabs that have less than batch_size objects (see shrink_slab_node()): while (total_scan >= batch_size) { shrinkctl->nr_to_scan = batch_size; shrinker->scan_objects(shrinker, shrinkctl); total_scan -= batch_size; } If there are only a few shrinkers available, such a behavior won't cause any problems, because the batch_size is usually small, but if we have a lot of slab shrinkers, which is perfectly possible since FS shrinkers are now per-superblock, we can end up with hundreds of megabytes of practically unreclaimable kmem objects. For instance, mounting a thousand of ext2 FS images with a hundred of files in each and iterating over all the files using du(1) will result in about 200 Mb of FS caches that cannot be dropped even with the aid of the vm.drop_caches sysctl! This problem was initially pointed out by Glauber Costa [*]. Glauber proposed to fix it by making the shrink_slab() always take at least one pass, to put it simply, turning the scan loop above to a do{}while() loop. However, this proposal was rejected, because it could result in more aggressive and frequent slab shrinking even under low memory pressure when total_scan is naturally very small. This patch is a slightly modified version of Glauber's approach. Similarly to Glauber's patch, it makes shrink_slab() scan less than batch_size objects, but only if the total number of objects we want to scan (total_scan) is greater than the total number of objects available (max_pass). Since total_scan is biased as half max_pass if the current delta change is small: if (delta < max_pass / 4) total_scan = min(total_scan, max_pass / 2); this is only possible if we are scanning at high prio. That said, this patch shouldn't change the vmscan behaviour if the memory pressure is low, but if we are tight on memory, we will do our best by trying to reclaim all available objects, which sounds reasonable. [*] http://www.spinics.net/lists/cgroups/msg06913.htmlSigned-off-by:
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Shaohua Li authored
commit 579f8290 upstream. This is a patch to improve swap readahead algorithm. It's from Hugh and I slightly changed it. Hugh's original changelog: swapin readahead does a blind readahead, whether or not the swapin is sequential. This may be ok on harddisk, because large reads have relatively small costs, and if the readahead pages are unneeded they can be reclaimed easily - though, what if their allocation forced reclaim of useful pages? But on SSD devices large reads are more expensive than small ones: if the readahead pages are unneeded, reading them in caused significant overhead. This patch adds very simplistic random read detection. Stealing the PageReadahead technique from Konstantin Khlebnikov's patch, avoiding the vma/anon_vma sophistications of Shaohua Li's patch, swapin_nr_pages() simply looks at readahead's current success rate, and narrows or widens its readahead window accordingly. There is little science to its heuristic: it's about as stupid as can be whilst remaining effective. The table below shows elapsed times (in centiseconds) when running a single repetitive swapping load across a 1000MB mapping in 900MB ram with 1GB swap (the harddisk tests had taken painfully too long when I used mem=500M, but SSD shows similar results for that). Vanilla is the 3.6-rc7 kernel on which I started; Shaohua denotes his Sep 3 patch in mmotm and linux-next; HughOld denotes my Oct 1 patch which Shaohua showed to be defective; HughNew this Nov 14 patch, with page_cluster as usual at default of 3 (8-page reads); HughPC4 this same patch with page_cluster 4 (16-page reads); HughPC0 with page_cluster 0 (1-page reads: no readahead). HDD for swapping to harddisk, SSD for swapping to VertexII SSD. Seq for sequential access to the mapping, cycling five times around; Rand for the same number of random touches. Anon for a MAP_PRIVATE anon mapping; Shmem for a MAP_SHARED anon mapping, equivalent to tmpfs. One weakness of Shaohua's vma/anon_vma approach was that it did not optimize Shmem: seen below. Konstantin's approach was perhaps mistuned, 50% slower on Seq: did not compete and is not shown below. HDD Vanilla Shaohua HughOld HughNew HughPC4 HughPC0 Seq Anon 73921 76210 75611 76904 78191 121542 Seq Shmem 73601 73176 73855 72947 74543 118322 Rand Anon 895392 831243 871569 845197 846496 841680 Rand Shmem 1058375 1053486 827935 764955 764376 756489 SSD Vanilla Shaohua HughOld HughNew HughPC4 HughPC0 Seq Anon 24634 24198 24673 25107 21614 70018 Seq Shmem 24959 24932 25052 25703 22030 69678 Rand Anon 43014 26146 28075 25989 26935 25901 Rand Shmem 45349 45215 28249 24268 24138 24332 These tests are, of course, two extremes of a very simple case: under heavier mixed loads I've not yet observed any consistent improvement or degradation, and wider testing would be welcome. Shaohua Li: Test shows Vanilla is slightly better in sequential workload than Hugh's patch. I observed with Hugh's patch sometimes the readahead size is shrinked too fast (from 8 to 1 immediately) in sequential workload if there is no hit. And in such case, continuing doing readahead is good actually. I don't prepare a sophisticated algorithm for the sequential workload because so far we can't guarantee sequential accessed pages are swap out sequentially. So I slightly change Hugh's heuristic - don't shrink readahead size too fast. Here is my test result (unit second, 3 runs average): Vanilla Hugh New Seq 356 370 360 Random 4525 2447 2444 Attached graph is the swapin/swapout throughput I collected with 'vmstat 2'. The first part is running a random workload (till around 1200 of the x-axis) and the second part is running a sequential workload. swapin and swapout throughput are almost identical in steady state in both workloads. These are expected behavior. while in Vanilla, swapin is much bigger than swapout especially in random workload (because wrong readahead). Original patches by: Shaohua Li and Konstantin Khlebnikov. [fengguang.wu@intel.com: swapin_nr_pages() can be static] Signed-off-by:
Shaohua Li <shli@fusionio.com> Signed-off-by:
Fengguang Wu <fengguang.wu@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Signed-off-by:
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Vlastimil Babka authored
commit 55b7c4c9 upstream. Compaction used to start its migrate and free page scaners at the zone's lowest and highest pfn, respectively. Later, caching was introduced to remember the scanners' progress across compaction attempts so that pageblocks are not re-scanned uselessly. Additionally, pageblocks where isolation failed are marked to be quickly skipped when encountered again in future compactions. Currently, both the reset of cached pfn's and clearing of the pageblock skip information for a zone is done in __reset_isolation_suitable(). This function gets called when: - compaction is restarting after being deferred - compact_blockskip_flush flag is set in compact_finished() when the scanners meet (and not again cleared when direct compaction succeeds in allocation) and kswapd acts upon this flag before going to sleep This behavior is suboptimal for several reasons: - when direct sync compaction is called after async compaction fails (in the allocation slowpath), it will effectively do nothing, unless kswapd happens to process the compact_blockskip_flush flag meanwhile. This is racy and goes against the purpose of sync compaction to more thoroughly retry the compaction of a zone where async compaction has failed. The restart-after-deferring path cannot help here as deferring happens only after the sync compaction fails. It is also done only for the preferred zone, while the compaction might be done for a fallback zone. - the mechanism of marking pageblock to be skipped has little value since the cached pfn's are reset only together with the pageblock skip flags. This effectively limits pageblock skip usage to parallel compactions. This patch changes compact_finished() so that cached pfn's are reset immediately when the scanners meet. Clearing pageblock skip flags is unchanged, as well as the other situations where cached pfn's are reset. This allows the sync-after-async compaction to retry pageblocks not marked as skipped, such as blocks !MIGRATE_MOVABLE blocks that async compactions now skips without marking them. Signed-off-by:
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Vlastimil Babka authored
commit 50b5b094 upstream. Compaction temporarily marks pageblocks where it fails to isolate pages as to-be-skipped in further compactions, in order to improve efficiency. One of the reasons to fail isolating pages is that isolation is not attempted in pageblocks that are not of MIGRATE_MOVABLE (or CMA) type. The problem is that blocks skipped due to not being MIGRATE_MOVABLE in async compaction become skipped due to the temporary mark also in future sync compaction. Moreover, this may follow quite soon during __alloc_page_slowpath, without much time for kswapd to clear the pageblock skip marks. This goes against the idea that sync compaction should try to scan these blocks more thoroughly than the async compaction. The fix is to ensure in async compaction that these !MIGRATE_MOVABLE blocks are not marked to be skipped. Note this should not affect performance or locking impact of further async compactions, as skipping a block due to being !MIGRATE_MOVABLE is done soon after skipping a block marked to be skipped, both without locking. Signed-off-by:
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Vlastimil Babka authored
commit de6c60a6 upstream. Currently there are several functions to manipulate the deferred compaction state variables. The remaining case where the variables are touched directly is when a successful allocation occurs in direct compaction, or is expected to be successful in the future by kswapd. Here, the lowest order that is expected to fail is updated, and in the case of successful allocation, the deferred status and counter is reset completely. Create a new function compaction_defer_reset() to encapsulate this functionality and make it easier to understand the code. No functional change. Signed-off-by:
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Mel Gorman authored
commit 0eb927c0 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:
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Mel Gorman authored
commit 71b54f82 upstream. When choosing between doing an address space or ranged flush, the x86 implementation of flush_tlb_mm_range takes into account whether there are any large pages in the range. A per-page flush typically requires fewer entries than would covered by a single large page and the check is redundant. There is one potential exception. THP migration flushes single THP entries and it conceivably would benefit from flushing a single entry instead of the mm. However, this flush is after a THP allocation, copy and page table update potentially with any other threads serialised behind it. In comparison to that, the flush is noise. It makes more sense to optimise balancing to require fewer flushes than to optimise the flush itself. This patch deletes the redundant huge page check. Signed-off-by:
Davidlohr Bueso <davidlohr@hp.com> Reviewed-by:
Ingo Molnar <mingo@kernel.org> Signed-off-by:
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Mel Gorman authored
commit 15aa3682 upstream. NR_TLB_LOCAL_FLUSH_ALL is not always accounted for correctly and the comparison with total_vm is done before taking tlb_flushall_shift into account. Clean it up. Signed-off-by:
Alex Shi <alex.shi@linaro.org> Reviewed-by:
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Mel Gorman authored
commit ec659934 upstream. Bisection between 3.11 and 3.12 fingered commit 9824cf97 ("mm: vmstats: tlb flush counters") to cause overhead problems. The counters are undeniably useful but how often do we really need to debug TLB flush related issues? It does not justify taking the penalty everywhere so make it a debugging option. Signed-off-by:
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KOSAKI Motohiro authored
commit 0cbef29a upstream. When __rmqueue_fallback() doesn't find a free block with the required size it splits a larger page and puts the rest of the page onto the free list. But it has one serious mistake. When putting back, __rmqueue_fallback() always use start_migratetype if type is not CMA. However, __rmqueue_fallback() is only called when all of the start_migratetype queue is empty. That said, __rmqueue_fallback always puts back memory to the wrong queue except try_to_steal_freepages() changed pageblock type (i.e. requested size is smaller than half of page block). The end result is that the antifragmentation framework increases fragmenation instead of decreasing it. Mel's original anti fragmentation does the right thing. But commit 47118af0 ("mm: mmzone: MIGRATE_CMA migration type added") broke it. This patch restores sane and old behavior. It also removes an incorrect comment which was introduced by commit fef903ef ("mm/page_alloc.c: restructure free-page stealing code and fix a bug"). Signed-off-by:
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KOSAKI Motohiro authored
commit 52c8f6a5 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:
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Damien Ramonda authored
commit af248a0c upstream. The kernel's readahead algorithm sometimes interprets random read accesses as sequential and triggers unnecessary data prefecthing from storage device (impacting random read average latency). In order to identify sequential cache read misses, the readahead algorithm intends to check whether offset - previous offset == 1 (trivial sequential reads) or offset - previous offset == 0 (sequential reads not aligned on page boundary): if (offset - (ra->prev_pos >> PAGE_CACHE_SHIFT) <= 1UL) The current offset is stored in the "offset" variable of type "pgoff_t" (unsigned long), while previous offset is stored in "ra->prev_pos" of type "loff_t" (long long). Therefore, operands of the if statement are implicitly converted to type long long. Consequently, when previous offset > current offset (which happens on random pattern), the if condition is true and access is wrongly interpeted as sequential. An unnecessary data prefetching is triggered, impacting the average random read latency. Storing the previous offset value in a "pgoff_t" variable (unsigned long) fixes the sequential read detection logic. Signed-off-by:
Damien Ramonda <damien.ramonda@intel.com> Reviewed-by:
Pierre Tardy <pierre.tardy@intel.com> Acked-by:
David Cohen <david.a.cohen@linux.intel.com> Signed-off-by:
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Dan Streetman authored
commit 18ab4d4c upstream. Originally get_swap_page() started iterating through the singly-linked list of swap_info_structs using swap_list.next or highest_priority_index, which both were intended to point to the highest priority active swap target that was not full. The first patch in this series changed the singly-linked list to a doubly-linked list, and removed the logic to start at the highest priority non-full entry; it starts scanning at the highest priority entry each time, even if the entry is full. Replace the manually ordered swap_list_head with a plist, swap_active_head. Add a new plist, swap_avail_head. The original swap_active_head plist contains all active swap_info_structs, as before, while the new swap_avail_head plist contains only swap_info_structs that are active and available, i.e. not full. Add a new spinlock, swap_avail_lock, to protect the swap_avail_head list. Mel Gorman suggested using plists since they internally handle ordering the list entries based on priority, which is exactly what swap was doing manually. All the ordering code is now removed, and swap_info_struct entries and simply added to their corresponding plist and automatically ordered correctly. Using a new plist for available swap_info_structs simplifies and optimizes get_swap_page(), which no longer has to iterate over full swap_info_structs. Using a new spinlock for swap_avail_head plist allows each swap_info_struct to add or remove themselves from the plist when they become full or not-full; previously they could not do so because the swap_info_struct->lock is held when they change from full<->not-full, and the swap_lock protecting the main swap_active_head must be ordered before any swap_info_struct->lock. Signed-off-by:
Dan Streetman <ddstreet@ieee.org> Acked-by:
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Dan Streetman authored
commit a75f232c upstream. Add plist_requeue(), which moves the specified plist_node after all other same-priority plist_nodes in the list. This is essentially an optimized plist_del() followed by plist_add(). This is needed by swap, which (with the next patch in this set) uses a plist of available swap devices. When a swap device (either a swap partition or swap file) are added to the system with swapon(), the device is added to a plist, ordered by the swap device's priority. When swap needs to allocate a page from one of the swap devices, it takes the page from the first swap device on the plist, which is the highest priority swap device. The swap device is left in the plist until all its pages are used, and then removed from the plist when it becomes full. However, as described in man 2 swapon, swap must allocate pages from swap devices with the same priority in round-robin order; to do this, on each swap page allocation, swap uses a page from the first swap device in the plist, and then calls plist_requeue() to move that swap device entry to after any other same-priority swap devices. The next swap page allocation will again use a page from the first swap device in the plist and requeue it, and so on, resulting in round-robin usage of equal-priority swap devices. Also add plist_test_requeue() test function, for use by plist_test() to test plist_requeue() function. Signed-off-by:
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Dan Streetman authored
commit fd16618e upstream. Add PLIST_HEAD() to plist.h, equivalent to LIST_HEAD() from list.h, to define and initialize a struct plist_head. Add plist_for_each_continue() and plist_for_each_entry_continue(), equivalent to list_for_each_continue() and list_for_each_entry_continue(), to iterate over a plist continuing after the current position. Add plist_prev() and plist_next(), equivalent to (struct list_head*)->prev and ->next, implemented by list_prev_entry() and list_next_entry(), to access the prev/next struct plist_node entry. These are needed because unlike struct list_head, direct access of the prev/next struct plist_node isn't possible; the list must be navigated via the contained struct list_head. e.g. instead of accessing the prev by list_prev_entry(node, node_list) it can be accessed by plist_prev(node). Signed-off-by:
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Dan Streetman authored
commit adfab836 upstream. The logic controlling the singly-linked list of swap_info_struct entries for all active, i.e. swapon'ed, swap targets is rather complex, because: - it stores the entries in priority order - there is a pointer to the highest priority entry - there is a pointer to the highest priority not-full entry - there is a highest_priority_index variable set outside the swap_lock - swap entries of equal priority should be used equally this complexity leads to bugs such as: https://lkml.org/lkml/2014/2/13/181 where different priority swap targets are incorrectly used equally. That bug probably could be solved with the existing singly-linked lists, but I think it would only add more complexity to the already difficult to understand get_swap_page() swap_list iteration logic. The first patch changes from a singly-linked list to a doubly-linked list using list_heads; the highest_priority_index and related code are removed and get_swap_page() starts each iteration at the highest priority swap_info entry, even if it's full. While this does introduce unnecessary list iteration (i.e. Schlemiel the painter's algorithm) in the case where one or more of the highest priority entries are full, the iteration and manipulation code is much simpler and behaves correctly re: the above bug; and the fourth patch removes the unnecessary iteration. The second patch adds some minor plist helper functions; nothing new really, just functions to match existing regular list functions. These are used by the next two patches. The third patch adds plist_requeue(), which is used by get_swap_page() in the next patch - it performs the requeueing of same-priority entries (which moves the entry to the end of its priority in the plist), so that all equal-priority swap_info_structs get used equally. The fourth patch converts the main list into a plist, and adds a new plist that contains only swap_info entries that are both active and not full. As Mel suggested using plists allows removing all the ordering code from swap - plists handle ordering automatically. The list naming is also clarified now that there are two lists, with the original list changed from swap_list_head to swap_active_head and the new list named swap_avail_head. A new spinlock is also added for the new list, so swap_info entries can be added or removed from the new list immediately as they become full or not full. This patch (of 4): Replace the singly-linked list tracking active, i.e. swapon'ed, swap_info_struct entries with a doubly-linked list using struct list_heads. Simplify the logic iterating and manipulating the list of entries, especially get_swap_page(), by using standard list_head functions, and removing the highest priority iteration logic. The change fixes the bug: https://lkml.org/lkml/2014/2/13/181 in which different priority swap entries after the highest priority entry are incorrectly used equally in pairs. The swap behavior is now as advertised, i.e. different priority swap entries are used in order, and equal priority swap targets are used concurrently. Signed-off-by:
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Michal Hocko authored
commit 70ef57e6 upstream. We had a report about strange OOM killer strikes on a PPC machine although there was a lot of swap free and a tons of anonymous memory which could be swapped out. In the end it turned out that the OOM was a side effect of zone reclaim which wasn't unmapping and swapping out and so the system was pushed to the OOM. Although this sounds like a bug somewhere in the kswapd vs. zone reclaim vs. direct reclaim interaction numactl on the said hardware suggests that the zone reclaim should not have been set in the first place: node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 node 0 size: 0 MB node 0 free: 0 MB node 2 cpus: node 2 size: 7168 MB node 2 free: 6019 MB node distances: node 0 2 0: 10 40 2: 40 10 So all the CPUs are associated with Node0 which doesn't have any memory while Node2 contains all the available memory. Node distances cause an automatic zone_reclaim_mode enabling. Zone reclaim is intended to keep the allocations local but this doesn't make any sense on the memoryless nodes. So let's exclude such nodes for init_zone_allows_reclaim which evaluates zone reclaim behavior and suitable reclaim_nodes. Signed-off-by:
Michal Hocko <mhocko@suse.cz> Acked-by:
Nishanth Aravamudan <nacc@linux.vnet.ibm.com> Tested-by:
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Nishanth Aravamudan authored
commit 457c1b27 upstream. Currently, I am seeing the following when I `mount -t hugetlbfs /none /dev/hugetlbfs`, and then simply do a `ls /dev/hugetlbfs`. I think it's related to the fact that hugetlbfs is properly not correctly setting itself up in this state?: Unable to handle kernel paging request for data at address 0x00000031 Faulting instruction address: 0xc000000000245710 Oops: Kernel access of bad area, sig: 11 [#1] SMP NR_CPUS=2048 NUMA pSeries .... In KVM guests on Power, in a guest not backed by hugepages, we see the following: AnonHugePages: 0 kB HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 64 kB HPAGE_SHIFT == 0 in this configuration, which indicates that hugepages are not supported at boot-time, but this is only checked in hugetlb_init(). Extract the check to a helper function, and use it in a few relevant places. This does make hugetlbfs not supported (not registered at all) in this environment. I believe this is fine, as there are no valid hugepages and that won't change at runtime. [akpm@linux-foundation.org: use pr_info(), per Mel] [akpm@linux-foundation.org: fix build when HPAGE_SHIFT is undefined] Signed-off-by:
Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by:
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Hugh Dickins authored
commit 88784396 upstream. Fix some "Bad rss-counter state" reports on exit, arising from the interaction between page migration and remap_file_pages(): zap_pte() must count a migration entry when zapping it. And yes, it is possible (though very unusual) to find an anon page or swap entry in a VM_SHARED nonlinear mapping: coming from that horrid get_user_pages(write, force) case which COWs even in a shared mapping. Signed-off-by:
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Han Pingtian authored
commit da8c757b upstream. If echo -1 > /proc/vm/sys/min_free_kbytes, the system will hang. Changing proc_dointvec() to proc_dointvec_minmax() in the min_free_kbytes_sysctl_handler() can prevent this to happen. mhocko said: : You can still do echo $BIG_VALUE > /proc/vm/sys/min_free_kbytes and make : your machine unusable but I agree that proc_dointvec_minmax is more : suitable here as we already have: : : .proc_handler = min_free_kbytes_sysctl_handler, : .extra1 = &zero, : : It used to work properly but then 6fce56ec ("sysctl: Remove references : to ctl_name and strategy from the generic sysctl table") has removed : sysctl_intvec strategy and so extra1 is ignored. Signed-off-by:
Han Pingtian <hanpt@linux.vnet.ibm.com> Acked-by:
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Joonsoo Kim authored
commit 73293c2f upstream. We checked pfmemalloc by slab unit, not page unit. You can see this in is_slab_pfmemalloc(). So other pages don't need to be set/cleared pfmemalloc. And, therefore we should check pfmemalloc in page flag of first page, but current implementation don't do that. virt_to_head_page(obj) just return 'struct page' of that object, not one of first page, since the SLAB don't use __GFP_COMP when CONFIG_MMU. To get 'struct page' of first page, we first get a slab and try to get it via virt_to_head_page(slab->s_mem). Acked-by:
Andi Kleen <ak@linux.intel.com> Signed-off-by:
Pekka Enberg <penberg@iki.fi> Signed-off-by:
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Bob Liu authored
commit 9f1b868a upstream. Khugepaged will scan/free HPAGE_PMD_NR normal pages and replace with a hugepage which is allocated from the node of the first scanned normal page, but this policy is too rough and may end with unexpected result to upper users. The problem is the original page-balancing among all nodes will be broken after hugepaged started. Thinking about the case if the first scanned normal page is allocated from node A, most of other scanned normal pages are allocated from node B or C.. But hugepaged will always allocate hugepage from node A which will cause extra memory pressure on node A which is not the situation before khugepaged started. This patch try to fix this problem by making khugepaged allocate hugepage from the node which have max record of scaned normal pages hit, so that the effect to original page-balancing can be minimized. The other problem is if normal scanned pages are equally allocated from Node A,B and C, after khugepaged started Node A will still suffer extra memory pressure. Andrew Davidoff reported a related issue several days ago. He wanted his application interleaving among all nodes and "numactl --interleave=all ./test" was used to run the testcase, but the result wasn't not as expected. cat /proc/2814/numa_maps: 7f50bd440000 interleave:0-3 anon=51403 dirty=51403 N0=435 N1=435 N2=435 N3=50098 The end result showed that most pages are from Node3 instead of interleave among node0-3 which was unreasonable. This patch also fix this issue by allocating hugepage round robin from all nodes have the same record, after this patch the result was as expected: 7f78399c0000 interleave:0-3 anon=51403 dirty=51403 N0=12723 N1=12723 N2=13235 N3=12722 The simple testcase is like this: int main() { char *p; int i; int j; for (i=0; i < 200; i++) { p = (char *)malloc(1048576); printf("malloc done\n"); if (p == 0) { printf("Out of memory\n"); return 1; } for (j=0; j < 1048576; j++) { p[j] = 'A'; } printf("touched memory\n"); sleep(1); } printf("enter sleep\n"); while(1) { sleep(100); } } [akpm@linux-foundation.org: make last_khugepaged_target_node local to khugepaged_find_target_node()] Reported-by:
Andrew Davidoff <davidoff@qedmf.net> Tested-by:
Bob Liu <bob.liu@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com> Signed-off-by:
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Bob Liu authored
commit 10dc4155 upstream. Move alloc_hugepage() to a better place, no need for a seperate #ifndef CONFIG_NUMA Signed-off-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Andrew Davidoff <davidoff@qedmf.net> Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com> Signed-off-by:
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Jiri Slaby authored
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Will Deacon authored
commit eb35bdd7 upstream. Nathan reports that we leak TLS information from the parent context during an exec, as we don't clear the TLS registers when flushing the thread state. This patch updates the flushing code so that we: (1) Unconditionally zero the tpidr_el0 register (since this is fully context switched for native tasks and zeroed for compat tasks) (2) Zero the tp_value state in thread_info before clearing the tpidrr0_el0 register for compat tasks (since this is only writable by the set_tls compat syscall and therefore not fully switched). A missing compiler barrier is also added to the compat set_tls syscall. Acked-by:
Nathan Lynch <Nathan_Lynch@mentor.com> Reported-by:
Will Deacon <will.deacon@arm.com> Signed-off-by:
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