- 14 11月, 2014 10 次提交
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由 Tang Chen 提交于
In free_area_init_core(), zone->managed_pages is set to an approximate value for lowmem, and will be adjusted when the bootmem allocator frees pages into the buddy system. But free_area_init_core() is also called by hotadd_new_pgdat() when hot-adding memory. As a result, zone->managed_pages of the newly added node's pgdat is set to an approximate value in the very beginning. Even if the memory on that node has node been onlined, /sys/device/system/node/nodeXXX/meminfo has wrong value: hot-add node2 (memory not onlined) cat /sys/device/system/node/node2/meminfo Node 2 MemTotal: 33554432 kB Node 2 MemFree: 0 kB Node 2 MemUsed: 33554432 kB Node 2 Active: 0 kB This patch fixes this problem by reset node managed pages to 0 after hot-adding a new node. 1. Move reset_managed_pages_done from reset_node_managed_pages() to reset_all_zones_managed_pages() 2. Make reset_node_managed_pages() non-static 3. Call reset_node_managed_pages() in hotadd_new_pgdat() after pgdat is initialized Signed-off-by: NTang Chen <tangchen@cn.fujitsu.com> Signed-off-by: NYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: <stable@vger.kernel.org> [3.16+] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Joonsoo Kim 提交于
One thing I did in this patch is fixing freepage accounting. If we clear guard page and link it onto isolate buddy list, we should not increase freepage count. This patch adds conditional branch to skip counting in this case. Without this patch, this overcounting happens frequently if guard order is set and CMA is used. Another thing fixed in this patch is the target to reset order. In __free_one_page(), we check the buddy page whether it is a guard page or not. And, if so, we should clear guard attribute on the buddy page and reset order of it to 0. But, current code resets original page's order rather than buddy one's. Maybe, this doesn't have any problem, because whole merged page's order will be re-assigned soon. But, it is better to correct code. Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: NVlastimil Babka <vbabka@suse.cz> Cc: Gioh Kim <gioh.kim@lge.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Vlastimil Babka 提交于
Several people have reported occasionally seeing processes stuck in compact_zone(), even triggering soft lockups, in 3.18-rc2+. Testing a revert of commit e14c720e ("mm, compaction: remember position within pageblock in free pages scanner") fixed the issue, although the stuck processes do not appear to involve the free scanner. Finally, by code inspection, the bug was found in isolate_migratepages() which uses a slightly different condition to detect if the migration and free scanners have met, than compact_finished(). That has not been a problem until commit e14c720e allowed the free scanner position between individual invocations to be in the middle of a pageblock. In a relatively rare case, the migration scanner position can end up at the beginning of a pageblock, with the free scanner position in the middle of the same pageblock. If it's the migration scanner's turn, isolate_migratepages() exits immediately (without updating the position), while compact_finished() decides to continue compaction, resulting in a potentially infinite loop. The system can recover only if another process creates enough high-order pages to make the watermark checks in compact_finished() pass. This patch fixes the immediate problem by bumping the migration scanner's position to meet the free scanner in isolate_migratepages(), when both are within the same pageblock. This causes compact_finished() to terminate properly. A more robust check in compact_finished() is planned as a cleanup for better future maintainability. Fixes: e14c720e ("mm, compaction: remember position within pageblock in free pages scanner) Signed-off-by: NVlastimil Babka <vbabka@suse.cz> Reported-by: NP. Christeas <xrg@linux.gr> Tested-by: NP. Christeas <xrg@linux.gr> Link: http://marc.info/?l=linux-mm&m=141508604232522&w=2Reported-by: NNorbert Preining <preining@logic.at> Tested-by: NNorbert Preining <preining@logic.at> Link: https://lkml.org/lkml/2014/11/4/904Reported-by: NPavel Machek <pavel@ucw.cz> Link: https://lkml.org/lkml/2014/11/7/164 Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Michal Nazarewicz 提交于
Having test_pages_isolated failure message as a warning confuses users into thinking that it is more serious than it really is. In reality, if called via CMA, allocation will be retried so a single test_pages_isolated failure does not prevent allocation from succeeding. Demote the warning message to an info message and reformat it such that the text "failed" does not appear and instead a less worrying "PFNS busy" is used. This message is trivially reproducible on a 10GB x86 machine on 3.16.y kernels configured with CONFIG_DMA_CMA. Signed-off-by: NMichal Nazarewicz <mina86@mina86.com> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Joonsoo Kim 提交于
Unlike SLUB, sometimes, object isn't started at the beginning of the slab in SLAB. This causes the unalignment problem after slab merging is supported by commit 12220dea ("mm/slab: support slab merge"). Following is the report from Markos that fail to boot on Malta with EVA. Calibrating delay loop... 19.86 BogoMIPS (lpj=99328) pid_max: default: 32768 minimum: 301 Mount-cache hash table entries: 4096 (order: 0, 16384 bytes) Mountpoint-cache hash table entries: 4096 (order: 0, 16384 bytes) Kernel bug detected[#1]: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.17.0-05639-g12220dea #1631 task: 1f04f5d8 ti: 1f050000 task.ti: 1f050000 epc : 80141190 alloc_unbound_pwq+0x234/0x304 Not tainted ra : 80141184 alloc_unbound_pwq+0x228/0x304 Process swapper/0 (pid: 1, threadinfo=1f050000, task=1f04f5d8, tls=00000000) Call Trace: alloc_unbound_pwq+0x234/0x304 apply_workqueue_attrs+0x11c/0x294 __alloc_workqueue_key+0x23c/0x470 init_workqueues+0x320/0x400 do_one_initcall+0xe8/0x23c kernel_init_freeable+0x9c/0x224 kernel_init+0x10/0x100 ret_from_kernel_thread+0x14/0x1c [ end trace cb88537fdc8fa200 ] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b alloc_unbound_pwq() allocates slab object from pool_workqueue. This kmem_cache requires 256 bytes alignment, but, current merging code doesn't honor that, and merge it with kmalloc-256. kmalloc-256 requires only cacheline size alignment so that above failure occurs. However, in x86, kmalloc-256 is luckily aligned in 256 bytes, so the problem didn't happen on it. To fix this problem, this patch introduces alignment mismatch check in find_mergeable(). This will fix the problem. Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com> Reported-by: NMarkos Chandras <Markos.Chandras@imgtec.com> Tested-by: NMarkos Chandras <Markos.Chandras@imgtec.com> Acked-by: NChristoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Joonsoo Kim 提交于
Current pageblock isolation logic could isolate each pageblock individually. This causes freepage accounting problem if freepage with pageblock order on isolate pageblock is merged with other freepage on normal pageblock. We can prevent merging by restricting max order of merging to pageblock order if freepage is on isolate pageblock. A side-effect of this change is that there could be non-merged buddy freepage even if finishing pageblock isolation, because undoing pageblock isolation is just to move freepage from isolate buddy list to normal buddy list rather than to consider merging. So, the patch also makes undoing pageblock isolation consider freepage merge. When un-isolation, freepage with more than pageblock order and it's buddy are checked. If they are on normal pageblock, instead of just moving, we isolate the freepage and free it in order to get merged. Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: NVlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Heesub Shin <heesub.shin@samsung.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Ritesh Harjani <ritesh.list@gmail.com> Cc: Gioh Kim <gioh.kim@lge.com> Cc: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Joonsoo Kim 提交于
All the caller of __free_one_page() has similar freepage counting logic, so we can move it to __free_one_page(). This reduce line of code and help future maintenance. This is also preparation step for "mm/page_alloc: restrict max order of merging on isolated pageblock" which fix the freepage counting problem on freepage with more than pageblock order. Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: NVlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Heesub Shin <heesub.shin@samsung.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Ritesh Harjani <ritesh.list@gmail.com> Cc: Gioh Kim <gioh.kim@lge.com> Cc: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Joonsoo Kim 提交于
In free_pcppages_bulk(), we use cached migratetype of freepage to determine type of buddy list where freepage will be added. This information is stored when freepage is added to pcp list, so if isolation of pageblock of this freepage begins after storing, this cached information could be stale. In other words, it has original migratetype rather than MIGRATE_ISOLATE. There are two problems caused by this stale information. One is that we can't keep these freepages from being allocated. Although this pageblock is isolated, freepage will be added to normal buddy list so that it could be allocated without any restriction. And the other problem is incorrect freepage accounting. Freepages on isolate pageblock should not be counted for number of freepage. Following is the code snippet in free_pcppages_bulk(). /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */ __free_one_page(page, page_to_pfn(page), zone, 0, mt); trace_mm_page_pcpu_drain(page, 0, mt); if (likely(!is_migrate_isolate_page(page))) { __mod_zone_page_state(zone, NR_FREE_PAGES, 1); if (is_migrate_cma(mt)) __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, 1); } As you can see above snippet, current code already handle second problem, incorrect freepage accounting, by re-fetching pageblock migratetype through is_migrate_isolate_page(page). But, because this re-fetched information isn't used for __free_one_page(), first problem would not be solved. This patch try to solve this situation to re-fetch pageblock migratetype before __free_one_page() and to use it for __free_one_page(). In addition to move up position of this re-fetch, this patch use optimization technique, re-fetching migratetype only if there is isolate pageblock. Pageblock isolation is rare event, so we can avoid re-fetching in common case with this optimization. This patch also correct migratetype of the tracepoint output. Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: NMinchan Kim <minchan@kernel.org> Acked-by: NMichal Nazarewicz <mina86@mina86.com> Acked-by: NVlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Heesub Shin <heesub.shin@samsung.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Ritesh Harjani <ritesh.list@gmail.com> Cc: Gioh Kim <gioh.kim@lge.com> Cc: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Joonsoo Kim 提交于
Before describing bugs itself, I first explain definition of freepage. 1. pages on buddy list are counted as freepage. 2. pages on isolate migratetype buddy list are *not* counted as freepage. 3. pages on cma buddy list are counted as CMA freepage, too. Now, I describe problems and related patch. Patch 1: There is race conditions on getting pageblock migratetype that it results in misplacement of freepages on buddy list, incorrect freepage count and un-availability of freepage. Patch 2: Freepages on pcp list could have stale cached information to determine migratetype of buddy list to go. This causes misplacement of freepages on buddy list and incorrect freepage count. Patch 4: Merging between freepages on different migratetype of pageblocks will cause freepages accouting problem. This patch fixes it. Without patchset [3], above problem doesn't happens on my CMA allocation test, because CMA reserved pages aren't used at all. So there is no chance for above race. With patchset [3], I did simple CMA allocation test and get below result: - Virtual machine, 4 cpus, 1024 MB memory, 256 MB CMA reservation - run kernel build (make -j16) on background - 30 times CMA allocation(8MB * 30 = 240MB) attempts in 5 sec interval - Result: more than 5000 freepage count are missed With patchset [3] and this patchset, I found that no freepage count are missed so that I conclude that problems are solved. On my simple memory offlining test, these problems also occur on that environment, too. This patch (of 4): There are two paths to reach core free function of buddy allocator, __free_one_page(), one is free_one_page()->__free_one_page() and the other is free_hot_cold_page()->free_pcppages_bulk()->__free_one_page(). Each paths has race condition causing serious problems. At first, this patch is focused on first type of freepath. And then, following patch will solve the problem in second type of freepath. In the first type of freepath, we got migratetype of freeing page without holding the zone lock, so it could be racy. There are two cases of this race. 1. pages are added to isolate buddy list after restoring orignal migratetype CPU1 CPU2 get migratetype => return MIGRATE_ISOLATE call free_one_page() with MIGRATE_ISOLATE grab the zone lock unisolate pageblock release the zone lock grab the zone lock call __free_one_page() with MIGRATE_ISOLATE freepage go into isolate buddy list, although pageblock is already unisolated This may cause two problems. One is that we can't use this page anymore until next isolation attempt of this pageblock, because freepage is on isolate buddy list. The other is that freepage accouting could be wrong due to merging between different buddy list. Freepages on isolate buddy list aren't counted as freepage, but ones on normal buddy list are counted as freepage. If merge happens, buddy freepage on normal buddy list is inevitably moved to isolate buddy list without any consideration of freepage accouting so it could be incorrect. 2. pages are added to normal buddy list while pageblock is isolated. It is similar with above case. This also may cause two problems. One is that we can't keep these freepages from being allocated. Although this pageblock is isolated, freepage would be added to normal buddy list so that it could be allocated without any restriction. And the other problem is same as case 1, that it, incorrect freepage accouting. This race condition would be prevented by checking migratetype again with holding the zone lock. Because it is somewhat heavy operation and it isn't needed in common case, we want to avoid rechecking as much as possible. So this patch introduce new variable, nr_isolate_pageblock in struct zone to check if there is isolated pageblock. With this, we can avoid to re-check migratetype in common case and do it only if there is isolated pageblock or migratetype is MIGRATE_ISOLATE. This solve above mentioned problems. Changes from v3: Add one more check in free_one_page() that checks whether migratetype is MIGRATE_ISOLATE or not. Without this, abovementioned case 1 could happens. Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: NMinchan Kim <minchan@kernel.org> Acked-by: NMichal Nazarewicz <mina86@mina86.com> Acked-by: NVlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Heesub Shin <heesub.shin@samsung.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Ritesh Harjani <ritesh.list@gmail.com> Cc: Gioh Kim <gioh.kim@lge.com> Cc: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Joonsoo Kim 提交于
Commit 7d49d886 ("mm, compaction: reduce zone checking frequency in the migration scanner") has a side-effect that changes the iteration range calculation. Before the change, block_end_pfn is calculated using start_pfn, but now it blindly adds pageblock_nr_pages to the previous value. This causes the problem that isolation_start_pfn is larger than block_end_pfn when we isolate the page with more than pageblock order. In this case, isolation would fail due to an invalid range parameter. To prevent this, this patch implements skipping the range until a proper target pageblock is met. Without this patch, CMA with more than pageblock order always fails but with this patch it will succeed. Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Minchan Kim <minchan@kernel.org> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 07 11月, 2014 1 次提交
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由 Jan Kara 提交于
XFS doesn't always hold i_mutex when calling truncate_setsize() and it uses a different lock to serialize truncates and writes. So fix the comment before truncate_setsize(). Reported-by: NJan Beulich <JBeulich@suse.com> Signed-off-by: NJan Kara <jack@suse.cz> Signed-off-by: NDave Chinner <david@fromorbit.com>
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- 30 10月, 2014 11 次提交
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由 Jan Kara 提交于
The WARN_ON checking whether i_mutex is held in pagecache_isize_extended() was wrong because some filesystems (e.g. XFS) use different locks for serialization of truncates / writes. So just remove the check. Signed-off-by: NJan Kara <jack@suse.cz> Reviewed-by: NDave Chinner <dchinner@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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由 Konstantin Khlebnikov 提交于
If CONFIG_BALLOON_COMPACTION=n balloon_page_insert() does not link pages with balloon and doesn't set PagePrivate flag, as a result balloon_page_dequeue() cannot get any pages because it thinks that all of them are isolated. Without balloon compaction nobody can isolate ballooned pages. It's safe to remove this check. Fixes: d6d86c0a ("mm/balloon_compaction: redesign ballooned pages management"). Signed-off-by: NKonstantin Khlebnikov <k.khlebnikov@samsung.com> Reported-by: NMatt Mullins <mmullins@mmlx.us> Cc: <stable@vger.kernel.org> [3.17] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Mikulas Patocka 提交于
The SLUB cache merges caches with the same size and alignment and there was long standing bug with this behavior: - create the cache named "foo" - create the cache named "bar" (which is merged with "foo") - delete the cache named "foo" (but it stays allocated because "bar" uses it) - create the cache named "foo" again - it fails because the name "foo" is already used That bug was fixed in commit 69461747 ("slab_common: fix the check for duplicate slab names") by not warning on duplicate cache names when the SLUB subsystem is used. Recently, cache merging was implemented the with SLAB subsystem too, in 12220dea ("mm/slab: support slab merge")). Therefore we need stop checking for duplicate names even for the SLAB subsystem. This patch fixes the bug by removing the check. Signed-off-by: NMikulas Patocka <mpatocka@redhat.com> Acked-by: NChristoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Johannes Weiner 提交于
page_remove_rmap() has too many branches on PageAnon() and is hard to follow. Move the file part into a separate function. Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org> Reviewed-by: NMichal Hocko <mhocko@suse.cz> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Johannes Weiner 提交于
Commit 0a31bc97 ("mm: memcontrol: rewrite uncharge API") changed page migration to uncharge the old page right away. The page is locked, unmapped, truncated, and off the LRU, but it could race with writeback ending, which then doesn't unaccount the page properly: test_clear_page_writeback() migration wait_on_page_writeback() TestClearPageWriteback() mem_cgroup_migrate() clear PCG_USED mem_cgroup_update_page_stat() if (PageCgroupUsed(pc)) decrease memcg pages under writeback release pc->mem_cgroup->move_lock The per-page statistics interface is heavily optimized to avoid a function call and a lookup_page_cgroup() in the file unmap fast path, which means it doesn't verify whether a page is still charged before clearing PageWriteback() and it has to do it in the stat update later. Rework it so that it looks up the page's memcg once at the beginning of the transaction and then uses it throughout. The charge will be verified before clearing PageWriteback() and migration can't uncharge the page as long as that is still set. The RCU lock will protect the memcg past uncharge. As far as losing the optimization goes, the following test results are from a microbenchmark that maps, faults, and unmaps a 4GB sparse file three times in a nested fashion, so that there are two negative passes that don't account but still go through the new transaction overhead. There is no actual difference: old: 33.195102545 seconds time elapsed ( +- 0.01% ) new: 33.199231369 seconds time elapsed ( +- 0.03% ) The time spent in page_remove_rmap()'s callees still adds up to the same, but the time spent in the function itself seems reduced: # Children Self Command Shared Object Symbol old: 0.12% 0.11% filemapstress [kernel.kallsyms] [k] page_remove_rmap new: 0.12% 0.08% filemapstress [kernel.kallsyms] [k] page_remove_rmap Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org> Acked-by: NMichal Hocko <mhocko@suse.cz> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: <stable@vger.kernel.org> [3.17.x] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Johannes Weiner 提交于
A follow-up patch would have changed the call signature. To save the trouble, just fold it instead. Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org> Acked-by: NMichal Hocko <mhocko@suse.cz> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: <stable@vger.kernel.org> [3.17.x] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Yasuaki Ishimatsu 提交于
When hot adding the same memory after hot removal, the following messages are shown: WARNING: CPU: 20 PID: 6 at mm/page_alloc.c:4968 free_area_init_node+0x3fe/0x426() ... Call Trace: dump_stack+0x46/0x58 warn_slowpath_common+0x81/0xa0 warn_slowpath_null+0x1a/0x20 free_area_init_node+0x3fe/0x426 hotadd_new_pgdat+0x90/0x110 add_memory+0xd4/0x200 acpi_memory_device_add+0x1aa/0x289 acpi_bus_attach+0xfd/0x204 acpi_bus_attach+0x178/0x204 acpi_bus_scan+0x6a/0x90 acpi_device_hotplug+0xe8/0x418 acpi_hotplug_work_fn+0x1f/0x2b process_one_work+0x14e/0x3f0 worker_thread+0x11b/0x510 kthread+0xe1/0x100 ret_from_fork+0x7c/0xb0 The detaled explanation is as follows: When hot removing memory, pgdat is set to 0 in try_offline_node(). But if the pgdat is allocated by bootmem allocator, the clearing step is skipped. And when hot adding the same memory, the uninitialized pgdat is reused. But free_area_init_node() checks wether pgdat is set to zero. As a result, free_area_init_node() hits WARN_ON(). This patch clears pgdat which is allocated by bootmem allocator in try_offline_node(). Signed-off-by: NYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Zhen <zhenzhang.zhang@huawei.com> Cc: Wang Nan <wangnan0@huawei.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Reviewed-by: NToshi Kani <toshi.kani@hp.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 David Rientjes 提交于
If an anonymous mapping is not allowed to fault thp memory and then madvise(MADV_HUGEPAGE) is used after fault, khugepaged will never collapse this memory into thp memory. This occurs because the madvise(2) handler for thp, hugepage_madvise(), clears VM_NOHUGEPAGE on the stack and it isn't stored in vma->vm_flags until the final action of madvise_behavior(). This causes the khugepaged_enter_vma_merge() to be a no-op in hugepage_madvise() when the vma had previously had VM_NOHUGEPAGE set. Fix this by passing the correct vma flags to the khugepaged mm slot handler. There's no chance khugepaged can run on this vma until after madvise_behavior() returns since we hold mm->mmap_sem. It would be possible to clear VM_NOHUGEPAGE directly from vma->vm_flags in hugepage_advise(), but I didn't want to introduce special case behavior into madvise_behavior(). I think it's best to just let it always set vma->vm_flags itself. Signed-off-by: NDavid Rientjes <rientjes@google.com> Reported-by: NSuleiman Souhlal <suleiman@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Yu Zhao 提交于
Compound page should be freed by put_page() or free_pages() with correct order. Not doing so will cause tail pages leaked. The compound order can be obtained by compound_order() or use HPAGE_PMD_ORDER in our case. Some people would argue the latter is faster but I prefer the former which is more general. This bug was observed not just on our servers (the worst case we saw is 11G leaked on a 48G machine) but also on our workstations running Ubuntu based distro. $ cat /proc/vmstat | grep thp_zero_page_alloc thp_zero_page_alloc 55 thp_zero_page_alloc_failed 0 This means there is (thp_zero_page_alloc - 1) * (2M - 4K) memory leaked. Fixes: 97ae1749 ("thp: implement refcounting for huge zero page") Signed-off-by: NYu Zhao <yuzhao@google.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: David Rientjes <rientjes@google.com> Cc: Bob Liu <lliubbo@gmail.com> Cc: <stable@vger.kernel.org> [3.8+] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Joonsoo Kim 提交于
Commit edc2ca61 ("mm, compaction: move pageblock checks up from isolate_migratepages_range()") commonizes isolate_migratepages variants and make them use isolate_migratepages_block(). isolate_migratepages_block() could stop the execution when enough pages are isolated, but, there is no code in isolate_migratepages_range() to handle this case. In the result, even if isolate_migratepages_block() returns prematurely without checking all pages in the range, isolate_migratepages_block() is called repeately on the following pageblock and some pages in the previous range are skipped to check. Then, CMA is failed frequently due to this fact. To fix this problem, this patch let isolate_migratepages_range() know the situation that enough pages are isolated and stop the isolation in that case. Note that isolate_migratepages() has no such problem, because, it always stops the isolation after just one call of isolate_migratepages_block(). Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: NVlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Christoph Lameter <cl@linux.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Wang Nan 提交于
Commit ff7ee93f ("cgroup/kmemleak: Annotate alloc_page() for cgroup allocations") introduces kmemleak_alloc() for alloc_page_cgroup(), but corresponding kmemleak_free() is missing, which makes kmemleak be wrongly disabled after memory offlining. Log is pasted at the end of this commit message. This patch add kmemleak_free() into free_page_cgroup(). During page offlining, this patch removes corresponding entries in kmemleak rbtree. After that, the freed memory can be allocated again by other subsystems without killing kmemleak. bash # for x in 1 2 3 4; do echo offline > /sys/devices/system/memory/memory$x/state ; sleep 1; done ; dmesg | grep leak Offlined Pages 32768 kmemleak: Cannot insert 0xffff880016969000 into the object search tree (overlaps existing) CPU: 0 PID: 412 Comm: sleep Not tainted 3.17.0-rc5+ #86 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Call Trace: dump_stack+0x46/0x58 create_object+0x266/0x2c0 kmemleak_alloc+0x26/0x50 kmem_cache_alloc+0xd3/0x160 __sigqueue_alloc+0x49/0xd0 __send_signal+0xcb/0x410 send_signal+0x45/0x90 __group_send_sig_info+0x13/0x20 do_notify_parent+0x1bb/0x260 do_exit+0x767/0xa40 do_group_exit+0x44/0xa0 SyS_exit_group+0x17/0x20 system_call_fastpath+0x16/0x1b kmemleak: Kernel memory leak detector disabled kmemleak: Object 0xffff880016900000 (size 524288): kmemleak: comm "swapper/0", pid 0, jiffies 4294667296 kmemleak: min_count = 0 kmemleak: count = 0 kmemleak: flags = 0x1 kmemleak: checksum = 0 kmemleak: backtrace: log_early+0x63/0x77 kmemleak_alloc+0x4b/0x50 init_section_page_cgroup+0x7f/0xf5 page_cgroup_init+0xc5/0xd0 start_kernel+0x333/0x408 x86_64_start_reservations+0x2a/0x2c x86_64_start_kernel+0xf5/0xfc Fixes: ff7ee93f (cgroup/kmemleak: Annotate alloc_page() for cgroup allocations) Signed-off-by: NWang Nan <wangnan0@huawei.com> Acked-by: NJohannes Weiner <hannes@cmpxchg.org> Acked-by: NMichal Hocko <mhocko@suse.cz> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: <stable@vger.kernel.org> [3.2+] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 29 10月, 2014 1 次提交
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由 Will Deacon 提交于
When unmapping a range of pages in zap_pte_range, the page being unmapped is added to an mmu_gather_batch structure for asynchronous freeing. If we run out of space in the batch structure before the range has been completely unmapped, then we break out of the loop, force a TLB flush and free the pages that we have batched so far. If there are further pages to unmap, then we resume the loop where we left off. Unfortunately, we forget to update addr when we break out of the loop, which causes us to truncate the range being invalidated as the end address is exclusive. When we re-enter the loop at the same address, the page has already been freed and the pte_present test will fail, meaning that we do not reconsider the address for invalidation. This patch fixes the problem by incrementing addr by the PAGE_SIZE before breaking out of the loop on batch failure. Signed-off-by: NWill Deacon <will.deacon@arm.com> Cc: stable@vger.kernel.org Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 27 10月, 2014 4 次提交
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由 Laurent Pinchart 提交于
Casting physical addresses to unsigned long and using %lu truncates the values on systems where physical addresses are larger than 32 bits. Use %pa and get rid of the cast instead. Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Acked-by: NMichal Nazarewicz <mina86@mina86.com> Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
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由 Laurent Pinchart 提交于
Commit 95b0e655 ("ARM: mm: don't limit default CMA region only to low memory") extended CMA memory reservation to allow usage of high memory. It relied on commit f7426b98 ("mm: cma: adjust address limit to avoid hitting low/high memory boundary") to ensure that the reserved block never crossed the low/high memory boundary. While the implementation correctly lowered the limit, it failed to consider the case where the base..limit range crossed the low/high memory boundary with enough space on each side to reserve the requested size on either low or high memory. Rework the base and limit adjustment to fix the problem. The function now starts by rejecting the reservation altogether for fixed reservations that cross the boundary, tries to reserve from high memory first and then falls back to low memory. Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
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由 Laurent Pinchart 提交于
The fixed parameter to cma_declare_contiguous() tells the function whether the given base address must be honoured or should be considered as a hint only. The API considers a zero base address as meaning any base address, which must never be considered as a fixed value. Part of the implementation correctly checks both fixed and base != 0, but two locations check the fixed value only. Set fixed to false when base is 0 to fix that and simplify the code. Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Acked-by: NMichal Nazarewicz <mina86@mina86.com> Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
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由 Laurent Pinchart 提交于
If activation of the CMA area fails its mutex won't be initialized, leading to an oops at allocation time when trying to lock the mutex. Fix this by setting the cma area count field to 0 when activation fails, leading to allocation returning NULL immediately. Cc: <stable@vger.kernel.org> # v3.17 Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Acked-by: NMichal Nazarewicz <mina86@mina86.com> Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
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- 24 10月, 2014 1 次提交
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由 Miklos Szeredi 提交于
Allocate a dentry, initialize it with a whiteout and hash it in the place of the old dentry. Later the old dentry will be moved away and the whiteout will remain. i_mutex protects agains concurrent readdir. Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz> Cc: Hugh Dickins <hughd@google.com>
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- 22 10月, 2014 1 次提交
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由 Michal Hocko 提交于
PM freezer relies on having all tasks frozen by the time devices are getting frozen so that no task will touch them while they are getting frozen. But OOM killer is allowed to kill an already frozen task in order to handle OOM situtation. In order to protect from late wake ups OOM killer is disabled after all tasks are frozen. This, however, still keeps a window open when a killed task didn't manage to die by the time freeze_processes finishes. Reduce the race window by checking all tasks after OOM killer has been disabled. This is still not race free completely unfortunately because oom_killer_disable cannot stop an already ongoing OOM killer so a task might still wake up from the fridge and get killed without freeze_processes noticing. Full synchronization of OOM and freezer is, however, too heavy weight for this highly unlikely case. Introduce and check oom_kills counter which gets incremented early when the allocator enters __alloc_pages_may_oom path and only check all the tasks if the counter changes during the freezing attempt. The counter is updated so early to reduce the race window since allocator checked oom_killer_disabled which is set by PM-freezing code. A false positive will push the PM-freezer into a slow path but that is not a big deal. Changes since v1 - push the re-check loop out of freeze_processes into check_frozen_processes and invert the condition to make the code more readable as per Rafael Fixes: f660daac (oom: thaw threads if oom killed thread is frozen before deferring) Cc: 3.2+ <stable@vger.kernel.org> # 3.2+ Signed-off-by: NMichal Hocko <mhocko@suse.cz> Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
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- 14 10月, 2014 4 次提交
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由 Peter Feiner 提交于
For VMAs that don't want write notifications, PTEs created for read faults have their write bit set. If the read fault happens after VM_SOFTDIRTY is cleared, then the PTE's softdirty bit will remain clear after subsequent writes. Here's a simple code snippet to demonstrate the bug: char* m = mmap(NULL, getpagesize(), PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0); system("echo 4 > /proc/$PPID/clear_refs"); /* clear VM_SOFTDIRTY */ assert(*m == '\0'); /* new PTE allows write access */ assert(!soft_dirty(x)); *m = 'x'; /* should dirty the page */ assert(soft_dirty(x)); /* fails */ With this patch, write notifications are enabled when VM_SOFTDIRTY is cleared. Furthermore, to avoid unnecessary faults, write notifications are disabled when VM_SOFTDIRTY is set. As a side effect of enabling and disabling write notifications with care, this patch fixes a bug in mprotect where vm_page_prot bits set by drivers were zapped on mprotect. An analogous bug was fixed in mmap by commit c9d0bf24 ("mm: uncached vma support with writenotify"). Signed-off-by: NPeter Feiner <pfeiner@google.com> Reported-by: NPeter Feiner <pfeiner@google.com> Suggested-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Jamie Liu <jamieliu@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Marek Szyprowski 提交于
Add a function to create CMA region from previously reserved memory and add support for handling 'shared-dma-pool' reserved-memory device tree nodes. Based on previous code provided by Josh Cartwright <joshc@codeaurora.org> Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Grant Likely <grant.likely@linaro.org> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Josh Cartwright <joshc@codeaurora.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Weijie Yang 提交于
The current cma bitmap aligned mask computation is incorrect. It could cause an unexpected alignment when using cma_alloc() if the wanted align order is larger than cma->order_per_bit. Take kvm for example (PAGE_SHIFT = 12), kvm_cma->order_per_bit is set to 6. When kvm_alloc_rma() tries to alloc kvm_rma_pages, it will use 15 as the expected align value. After using the current implementation however, we get 0 as cma bitmap aligned mask other than 511. This patch fixes the cma bitmap aligned mask calculation. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: NWeijie Yang <weijie.yang@samsung.com> Acked-by: NMichal Nazarewicz <mina86@mina86.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> [3.17] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Joonsoo Kim 提交于
Commit bf0dea23 ("mm/slab: use percpu allocator for cpu cache") changed the allocation method for cpu cache array from slab allocator to percpu allocator. Alignment should be provided for aligned memory in percpu allocator case, but, that commit mistakenly set this alignment to 0. So, percpu allocator returns unaligned memory address. It doesn't cause any problem on x86 which permits unaligned access, but, it causes the problem on sparc64 which needs strong guarantee of alignment. Following bug report is reported from David Miller. I'm getting tons of the following on sparc64: [603965.383447] Kernel unaligned access at TPC[546b58] free_block+0x98/0x1a0 [603965.396987] Kernel unaligned access at TPC[546b60] free_block+0xa0/0x1a0 ... [603970.554394] log_unaligned: 333 callbacks suppressed ... This patch provides a proper alignment parameter when allocating cpu cache to fix this unaligned memory access problem on sparc64. Reported-by: NDavid Miller <davem@davemloft.net> Tested-by: NDavid Miller <davem@davemloft.net> Tested-by: NMeelis Roos <mroos@linux.ee> Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 11 10月, 2014 1 次提交
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由 Josh Triplett 提交于
Commit d3ac21ca ("mm: Support compiling out madvise and fadvise") incorrectly made fadvise conditional on CONFIG_MMU. (The merged branch unintentionally incorporated v1 of the patch rather than the fixed v2.) Apply the delta from v1 to v2, to allow fadvise without CONFIG_MMU. Reported-by: NJohannes Weiner <hannes@cmpxchg.org> Signed-off-by: NJosh Triplett <josh@joshtriplett.org>
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- 10 10月, 2014 6 次提交
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由 Chao Yu 提交于
For now, there are NCHUNKS of 64 freelists in zbud_pool, the last unbuddied[63] freelist linked with all zbud pages which have free chunks of 63. Calculating according to context of num_free_chunks(), our max chunk number of unbuddied zbud page is 62, so none of zbud pages will be added/removed in last freelist, but still we will try to find an unbuddied zbud page in the last unused freelist, it is unneeded. This patch redefines NCHUNKS to 63 as free chunk number in one zbud page, hence we can decrease size of zpool and avoid accessing the last unused freelist whenever failing to allocate zbud from freelist in zbud_alloc. Signed-off-by: NChao Yu <chao2.yu@samsung.com> Cc: Seth Jennings <sjennings@variantweb.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Dan Streetman 提交于
Change zsmalloc init_zspage() logic to iterate through each object on each of its pages, checking the offset to verify the object is on the current page before linking it into the zspage. The current zsmalloc init_zspage free object linking code has logic that relies on there only being one page per zspage when PAGE_SIZE is a multiple of class->size. It calculates the number of objects for the current page, and iterates through all of them plus one, to account for the assumed partial object at the end of the page. While this currently works, the logic can be simplified to just link the object at each successive offset until the offset is larger than PAGE_SIZE, which does not rely on PAGE_SIZE being a multiple of class->size. Signed-off-by: NDan Streetman <ddstreet@ieee.org> Acked-by: NMinchan Kim <minchan@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Seth Jennings <sjennings@variantweb.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Wang Sheng-Hui 提交于
The letter 'f' in "n <= N/f" stands for fullness_threshold_frac, not 1/fullness_threshold_frac. Signed-off-by: NWang Sheng-Hui <shhuiw@gmail.com> Acked-by: NMinchan Kim <minchan@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Minchan Kim 提交于
zs_get_total_size_bytes returns a amount of memory zsmalloc consumed with *byte unit* but zsmalloc operates *page unit* rather than byte unit so let's change the API so benefit we could get is that reduce unnecessary overhead (ie, change page unit with byte unit) in zsmalloc. Since return type is pages, "zs_get_total_pages" is better than "zs_get_total_size_bytes". Signed-off-by: NMinchan Kim <minchan@kernel.org> Reviewed-by: NDan Streetman <ddstreet@ieee.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: <juno.choi@lge.com> Cc: <seungho1.park@lge.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: David Horner <ds2horner@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Minchan Kim 提交于
Currently, zram has no feature to limit memory so theoretically zram can deplete system memory. Users have asked for a limit several times as even without exhaustion zram makes it hard to control memory usage of the platform. This patchset adds the feature. Patch 1 makes zs_get_total_size_bytes faster because it would be used frequently in later patches for the new feature. Patch 2 changes zs_get_total_size_bytes's return unit from bytes to page so that zsmalloc doesn't need unnecessary operation(ie, << PAGE_SHIFT). Patch 3 adds new feature. I added the feature into zram layer, not zsmalloc because limiation is zram's requirement, not zsmalloc so any other user using zsmalloc(ie, zpool) shouldn't affected by unnecessary branch of zsmalloc. In future, if every users of zsmalloc want the feature, then, we could move the feature from client side to zsmalloc easily but vice versa would be painful. Patch 4 adds news facility to report maximum memory usage of zram so that this avoids user polling frequently via /sys/block/zram0/ mem_used_total and ensures transient max are not missed. This patch (of 4): pages_allocated has counted in size_class structure and when user of zsmalloc want to see total_size_bytes, it should gather all of count from each size_class to report the sum. It's not bad if user don't see the value often but if user start to see the value frequently, it would be not a good deal for performance pov. This patch moves the count from size_class to zs_pool so it could reduce memory footprint (from [255 * 8byte] to [sizeof(atomic_long_t)]). Signed-off-by: NMinchan Kim <minchan@kernel.org> Reviewed-by: NDan Streetman <ddstreet@ieee.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: <juno.choi@lge.com> Cc: <seungho1.park@lge.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Seth Jennings <sjennings@variantweb.net> Reviewed-by: NDavid Horner <ds2horner@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
vmstat workers are used for folding counter differentials into the zone, per node and global counters at certain time intervals. They currently run at defined intervals on all processors which will cause some holdoff for processors that need minimal intrusion by the OS. The current vmstat_update mechanism depends on a deferrable timer firing every other second by default which registers a work queue item that runs on the local CPU, with the result that we have 1 interrupt and one additional schedulable task on each CPU every 2 seconds If a workload indeed causes VM activity or multiple tasks are running on a CPU, then there are probably bigger issues to deal with. However, some workloads dedicate a CPU for a single CPU bound task. This is done in high performance computing, in high frequency financial applications, in networking (Intel DPDK, EZchip NPS) and with the advent of systems with more and more CPUs over time, this may become more and more common to do since when one has enough CPUs one cares less about efficiently sharing a CPU with other tasks and more about efficiently monopolizing a CPU per task. The difference of having this timer firing and workqueue kernel thread scheduled per second can be enormous. An artificial test measuring the worst case time to do a simple "i++" in an endless loop on a bare metal system and under Linux on an isolated CPU with dynticks and with and without this patch, have Linux match the bare metal performance (~700 cycles) with this patch and loose by couple of orders of magnitude (~200k cycles) without it[*]. The loss occurs for something that just calculates statistics. For networking applications, for example, this could be the difference between dropping packets or sustaining line rate. Statistics are important and useful, but it would be great if there would be a way to not cause statistics gathering produce a huge performance difference. This patche does just that. This patch creates a vmstat shepherd worker that monitors the per cpu differentials on all processors. If there are differentials on a processor then a vmstat worker local to the processors with the differentials is created. That worker will then start folding the diffs in regular intervals. Should the worker find that there is no work to be done then it will make the shepherd worker monitor the differentials again. With this patch it is possible then to have periods longer than 2 seconds without any OS event on a "cpu" (hardware thread). The patch shows a very minor increased in system performance. hackbench -s 512 -l 2000 -g 15 -f 25 -P Results before the patch: Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks) Each sender will pass 2000 messages of 512 bytes Time: 4.992 Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks) Each sender will pass 2000 messages of 512 bytes Time: 4.971 Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks) Each sender will pass 2000 messages of 512 bytes Time: 5.063 Hackbench after the patch: Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks) Each sender will pass 2000 messages of 512 bytes Time: 4.973 Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks) Each sender will pass 2000 messages of 512 bytes Time: 4.990 Running in process mode with 15 groups using 50 file descriptors each (== 750 tasks) Each sender will pass 2000 messages of 512 bytes Time: 4.993 [fengguang.wu@intel.com: cpu_stat_off can be static] Signed-off-by: NChristoph Lameter <cl@linux.com> Reviewed-by: NGilad Ben-Yossef <gilad@benyossef.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tejun Heo <tj@kernel.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Max Krasnyansky <maxk@qti.qualcomm.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Hugh Dickins <hughd@google.com> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: NFengguang Wu <fengguang.wu@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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