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* mm: remove rest of ACCESS_ONCE() usagesJason Low2015-04-151-3/+3
| | | | | | | | | | | | | | | | | We converted some of the usages of ACCESS_ONCE to READ_ONCE in the mm/ tree since it doesn't work reliably on non-scalar types. This patch removes the rest of the usages of ACCESS_ONCE, and use the new READ_ONCE API for the read accesses. This makes things cleaner, instead of using separate/multiple sets of APIs. Signed-off-by: Jason Low <jason.low2@hp.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Davidlohr Bueso <dave@stgolabs.net> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/page_alloc.c: clean up commentYaowei Bai2015-04-141-1/+1
| | | | | | Signed-off-by: Yaowei Bai <bywxiaobai@163.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: remove GFP_THISNODEDavid Rientjes2015-04-141-16/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | NOTE: this is not about __GFP_THISNODE, this is only about GFP_THISNODE. GFP_THISNODE is a secret combination of gfp bits that have different behavior than expected. It is a combination of __GFP_THISNODE, __GFP_NORETRY, and __GFP_NOWARN and is special-cased in the page allocator slowpath to fail without trying reclaim even though it may be used in combination with __GFP_WAIT. An example of the problem this creates: commit e97ca8e5b864 ("mm: fix GFP_THISNODE callers and clarify") fixed up many users of GFP_THISNODE that really just wanted __GFP_THISNODE. The problem doesn't end there, however, because even it was a no-op for alloc_misplaced_dst_page(), which also sets __GFP_NORETRY and __GFP_NOWARN, and migrate_misplaced_transhuge_page(), where __GFP_NORETRY and __GFP_NOWAIT is set in GFP_TRANSHUGE. Converting GFP_THISNODE to __GFP_THISNODE is a no-op in these cases since the page allocator special-cases __GFP_THISNODE && __GFP_NORETRY && __GFP_NOWARN. It's time to just remove GFP_THISNODE entirely. We leave __GFP_THISNODE to restrict an allocation to a local node, but remove GFP_THISNODE and its obscurity. Instead, we require that a caller clear __GFP_WAIT if it wants to avoid reclaim. This allows the aforementioned functions to actually reclaim as they should. It also enables any future callers that want to do __GFP_THISNODE but also __GFP_NORETRY && __GFP_NOWARN to reclaim. The rule is simple: if you don't want to reclaim, then don't set __GFP_WAIT. Aside: ovs_flow_stats_update() really wants to avoid reclaim as well, so it is unchanged. Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Pravin Shelar <pshelar@nicira.com> Cc: Jarno Rajahalme <jrajahalme@nicira.com> Cc: Li Zefan <lizefan@huawei.com> Cc: Greg Thelen <gthelen@google.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: completely remove dumping per-cpu lists from show_mem()Konstantin Khlebnikov2015-04-141-20/+2
| | | | | | | | | | It seems nobody needs this. Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: hide per-cpu lists in output of show_mem()Konstantin Khlebnikov2015-04-141-9/+30
| | | | | | | | | | | | | | | This makes show_mem() much less verbose on huge machines. Instead of huge and almost useless dump of counters for each per-zone per-cpu lists this patch prints the sum of these counters for each zone (free_pcp) and size of per-cpu list for current cpu (local_pcp). The filter flag SHOW_MEM_PERCPU_LISTS reverts to the old verbose mode. [akpm@linux-foundation.org: update show_free_areas comment] Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/compaction: enhance compaction finish conditionJoonsoo Kim2015-04-141-5/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Compaction has anti fragmentation algorithm. It is that freepage should be more than pageblock order to finish the compaction if we don't find any freepage in requested migratetype buddy list. This is for mitigating fragmentation, but, there is a lack of migratetype consideration and it is too excessive compared to page allocator's anti fragmentation algorithm. Not considering migratetype would cause premature finish of compaction. For example, if allocation request is for unmovable migratetype, freepage with CMA migratetype doesn't help that allocation and compaction should not be stopped. But, current logic regards this situation as compaction is no longer needed, so finish the compaction. Secondly, condition is too excessive compared to page allocator's logic. We can steal freepage from other migratetype and change pageblock migratetype on more relaxed conditions in page allocator. This is designed to prevent fragmentation and we can use it here. Imposing hard constraint only to the compaction doesn't help much in this case since page allocator would cause fragmentation again. To solve these problems, this patch borrows anti fragmentation logic from page allocator. It will reduce premature compaction finish in some cases and reduce excessive compaction work. stress-highalloc test in mmtests with non movable order 7 allocation shows considerable increase of compaction success rate. Compaction success rate (Compaction success * 100 / Compaction stalls, %) 31.82 : 42.20 I tested it on non-reboot 5 runs stress-highalloc benchmark and found that there is no more degradation on allocation success rate than before. That roughly means that this patch doesn't result in more fragmentations. Vlastimil suggests additional idea that we only test for fallbacks when migration scanner has scanned a whole pageblock. It looked good for fragmentation because chance of stealing increase due to making more free pages in certain pageblock. So, I tested it, but, it results in decreased compaction success rate, roughly 38.00. I guess the reason that if system is low memory condition, watermark check could be failed due to not enough order 0 free page and so, sometimes, we can't reach a fallback check although migrate_pfn is aligned to pageblock_nr_pages. I can insert code to cope with this situation but it makes code more complicated so I don't include his idea at this patch. [akpm@linux-foundation.org: fix CONFIG_CMA=n build] Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/page_alloc: factor out fallback freepage checkingJoonsoo Kim2015-04-141-52/+91
| | | | | | | | | | | | | | | | This is preparation step to use page allocator's anti fragmentation logic in compaction. This patch just separates fallback freepage checking part from fallback freepage management part. Therefore, there is no functional change. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/cma: change fallback behaviour for CMA freepageJoonsoo Kim2015-04-141-17/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Freepage with MIGRATE_CMA can be used only for MIGRATE_MOVABLE and they should not be expanded to other migratetype buddy list to protect them from unmovable/reclaimable allocation. Implementing these requirements in __rmqueue_fallback(), that is, finding largest possible block of freepage has bad effect that high order freepage with MIGRATE_CMA are broken continually although there are suitable order CMA freepage. Reason is that they are not be expanded to other migratetype buddy list and next __rmqueue_fallback() invocation try to finds another largest block of freepage and break it again. So, MIGRATE_CMA fallback should be handled separately. This patch introduces __rmqueue_cma_fallback(), that just wrapper of __rmqueue_smallest() and call it before __rmqueue_fallback() if migratetype == MIGRATE_MOVABLE. This results in unintended behaviour change that MIGRATE_CMA freepage is always used first rather than other migratetype as movable allocation's fallback. But, as already mentioned above, MIGRATE_CMA can be used only for MIGRATE_MOVABLE, so it is better to use MIGRATE_CMA freepage first as much as possible. Otherwise, we needlessly take up precious freepages with other migratetype and increase chance of fragmentation. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, oom: do not fail __GFP_NOFAIL allocation if oom killer is disabledMichal Hocko2015-03-121-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Tetsuo Handa has pointed out that __GFP_NOFAIL allocations might fail after OOM killer is disabled if the allocation is performed by a kernel thread. This behavior was introduced from the very beginning by 7f33d49a2ed5 ("mm, PM/Freezer: Disable OOM killer when tasks are frozen"). This means that the basic contract for the allocation request is broken and the context requesting such an allocation might blow up unexpectedly. There are basically two ways forward. 1) move oom_killer_disable after kernel threads are frozen. This has a risk that the OOM victim wouldn't be able to finish because it would depend on an already frozen kernel thread. This would be really tricky to debug. 2) do not fail GFP_NOFAIL allocation no matter what and risk a potential Freezable kernel threads will loop and fail the suspend. Incidental allocations after kernel threads are frozen will at least dump a warning - if we are lucky and the serial console is still active of course... This patch implements the later option because it is safer. We would see warning rather than allocation failures for the kernel threads which would blow up otherwise and have a higher chances to identify __GFP_NOFAIL users from deeper pm code. Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: David Rientjes <rientjes@gooogle.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: page_alloc: revert inadvertent !__GFP_FS retry behavior changeJohannes Weiner2015-02-281-1/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Historically, !__GFP_FS allocations were not allowed to invoke the OOM killer once reclaim had failed, but nevertheless kept looping in the allocator. Commit 9879de7373fc ("mm: page_alloc: embed OOM killing naturally into allocation slowpath"), which should have been a simple cleanup patch, accidentally changed the behavior to aborting the allocation at that point. This creates problems with filesystem callers (?) that currently rely on the allocator waiting for other tasks to intervene. Revert the behavior as it shouldn't have been changed as part of a cleanup patch. Fixes: 9879de7373fc ("mm: page_alloc: embed OOM killing naturally into allocation slowpath") Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Dave Chinner <david@fromorbit.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: <stable@vger.kernel.org> [3.19.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: page_alloc: add kasan hooks on alloc and free pathsAndrey Ryabinin2015-02-131-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | Add kernel address sanitizer hooks to mark allocated page's addresses as accessible in corresponding shadow region. Mark freed pages as inaccessible. Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrey Konovalov <adech.fo@gmail.com> Cc: Yuri Gribov <tetra2005@gmail.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/page_alloc: fix commentYaowei Bai2015-02-121-1/+1
| | | | | | | | Add a necessary 'leave'. Signed-off-by: Yaowei Bai <bywxiaobai@163.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/page_alloc.c: pull out init code from build_all_zonelistsRasmus Villemoes2015-02-121-3/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Pulling the code protected by if (system_state == SYSTEM_BOOTING) into its own helper allows us to shrink .text a little. This relies on build_all_zonelists already having a __ref annotation. Add a comment explaining why so one doesn't have to track it down through git log. The real saving comes in 3/5, ("mm/mm_init.c: Mark mminit_verify_zonelist as __init"), where we save about 400 bytes Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Rik van Riel <riel@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Cc: Vishnu Pratap Singh <vishnu.ps@samsung.com> Cc: Pintu Kumar <pintu.k@samsung.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Li Zefan <lizefan@huawei.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: more aggressive page stealing for UNMOVABLE allocationsVlastimil Babka2015-02-111-4/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When allocation falls back to stealing free pages of another migratetype, it can decide to steal extra pages, or even the whole pageblock in order to reduce fragmentation, which could happen if further allocation fallbacks pick a different pageblock. In try_to_steal_freepages(), one of the situations where extra pages are stolen happens when we are trying to allocate a MIGRATE_RECLAIMABLE page. However, MIGRATE_UNMOVABLE allocations are not treated the same way, although spreading such allocation over multiple fallback pageblocks is arguably even worse than it is for RECLAIMABLE allocations. To minimize fragmentation, we should minimize the number of such fallbacks, and thus steal as much as is possible from each fallback pageblock. Note that in theory this might put more pressure on movable pageblocks and cause movable allocations to steal back from unmovable pageblocks. However, movable allocations are not as aggressive with stealing, and do not cause permanent fragmentation, so the tradeoff is reasonable, and evaluation seems to support the change. This patch thus adds a check for MIGRATE_UNMOVABLE to the decision to steal extra free pages. When evaluating with stress-highalloc from mmtests, this has reduced the number of MIGRATE_UNMOVABLE fallbacks to roughly 1/6. The number of these fallbacks stealing from MIGRATE_MOVABLE block is reduced to 1/3. There was no observation of growing number of unmovable pageblocks over time, and also not of increased movable allocation fallbacks. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Minchan Kim <minchan@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: always steal split buddies in fallback allocationsVlastimil Babka2015-02-111-33/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When allocation falls back to another migratetype, it will steal a page with highest available order, and (depending on this order and desired migratetype), it might also steal the rest of free pages from the same pageblock. Given the preference of highest available order, it is likely that it will be higher than the desired order, and result in the stolen buddy page being split. The remaining pages after split are currently stolen only when the rest of the free pages are stolen. This can however lead to situations where for MOVABLE allocations we split e.g. order-4 fallback UNMOVABLE page, but steal only order-0 page. Then on the next MOVABLE allocation (which may be batched to fill the pcplists) we split another order-3 or higher page, etc. By stealing all pages that we have split, we can avoid further stealing. This patch therefore adjusts the page stealing so that buddy pages created by split are always stolen. This has effect only on MOVABLE allocations, as RECLAIMABLE and UNMOVABLE allocations already always do that in addition to stealing the rest of free pages from the pageblock. The change also allows to simplify try_to_steal_freepages() and factor out CMA handling. According to Mel, it has been intended since the beginning that buddy pages after split would be stolen always, but it doesn't seem like it was ever the case until commit 47118af076f6 ("mm: mmzone: MIGRATE_CMA migration type added"). The commit has unintentionally introduced this behavior, but was reverted by commit 0cbef29a7821 ("mm: __rmqueue_fallback() should respect pageblock type"). Neither included evaluation. My evaluation with stress-highalloc from mmtests shows about 2.5x reduction of page stealing events for MOVABLE allocations, without affecting the page stealing events for other allocation migratetypes. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: when stealing freepages, also take pages created by splitting buddy pageVlastimil Babka2015-02-111-7/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When studying page stealing, I noticed some weird looking decisions in try_to_steal_freepages(). The first I assume is a bug (Patch 1), the following two patches were driven by evaluation. Testing was done with stress-highalloc of mmtests, using the mm_page_alloc_extfrag tracepoint and postprocessing to get counts of how often page stealing occurs for individual migratetypes, and what migratetypes are used for fallbacks. Arguably, the worst case of page stealing is when UNMOVABLE allocation steals from MOVABLE pageblock. RECLAIMABLE allocation stealing from MOVABLE allocation is also not ideal, so the goal is to minimize these two cases. The evaluation of v2 wasn't always clear win and Joonsoo questioned the results. Here I used different baseline which includes RFC compaction improvements from [1]. I found that the compaction improvements reduce variability of stress-highalloc, so there's less noise in the data. First, let's look at stress-highalloc configured to do sync compaction, and how these patches reduce page stealing events during the test. First column is after fresh reboot, other two are reiterations of test without reboot. That was all accumulater over 5 re-iterations (so the benchmark was run 5x3 times with 5 fresh restarts). Baseline: 3.19-rc4 3.19-rc4 3.19-rc4 5-nothp-1 5-nothp-2 5-nothp-3 Page alloc extfrag event 10264225 8702233 10244125 Extfrag fragmenting 10263271 8701552 10243473 Extfrag fragmenting for unmovable 13595 17616 15960 Extfrag fragmenting unmovable placed with movable 7989 12193 8447 Extfrag fragmenting for reclaimable 658 1840 1817 Extfrag fragmenting reclaimable placed with movable 558 1677 1679 Extfrag fragmenting for movable 10249018 8682096 10225696 With Patch 1: 3.19-rc4 3.19-rc4 3.19-rc4 6-nothp-1 6-nothp-2 6-nothp-3 Page alloc extfrag event 11834954 9877523 9774860 Extfrag fragmenting 11833993 9876880 9774245 Extfrag fragmenting for unmovable 7342 16129 11712 Extfrag fragmenting unmovable placed with movable 4191 10547 6270 Extfrag fragmenting for reclaimable 373 1130 923 Extfrag fragmenting reclaimable placed with movable 302 906 738 Extfrag fragmenting for movable 11826278 9859621 9761610 With Patch 2: 3.19-rc4 3.19-rc4 3.19-rc4 7-nothp-1 7-nothp-2 7-nothp-3 Page alloc extfrag event 4725990 3668793 3807436 Extfrag fragmenting 4725104 3668252 3806898 Extfrag fragmenting for unmovable 6678 7974 7281 Extfrag fragmenting unmovable placed with movable 2051 3829 4017 Extfrag fragmenting for reclaimable 429 1208 1278 Extfrag fragmenting reclaimable placed with movable 369 976 1034 Extfrag fragmenting for movable 4717997 3659070 3798339 With Patch 3: 3.19-rc4 3.19-rc4 3.19-rc4 8-nothp-1 8-nothp-2 8-nothp-3 Page alloc extfrag event 5016183 4700142 3850633 Extfrag fragmenting 5015325 4699613 3850072 Extfrag fragmenting for unmovable 1312 3154 3088 Extfrag fragmenting unmovable placed with movable 1115 2777 2714 Extfrag fragmenting for reclaimable 437 1193 1097 Extfrag fragmenting reclaimable placed with movable 330 969 879 Extfrag fragmenting for movable 5013576 4695266 3845887 In v2 we've seen apparent regression with Patch 1 for unmovable events, this is now gone, suggesting it was indeed noise. Here, each patch improves the situation for unmovable events. Reclaimable is improved by patch 1 and then either the same modulo noise, or perhaps sligtly worse - a small price for unmovable improvements, IMHO. The number of movable allocations falling back to other migratetypes is most noisy, but it's reduced to half at Patch 2 nevertheless. These are least critical as compaction can move them around. If we look at success rates, the patches don't affect them, that didn't change. Baseline: 3.19-rc4 3.19-rc4 3.19-rc4 5-nothp-1 5-nothp-2 5-nothp-3 Success 1 Min 49.00 ( 0.00%) 42.00 ( 14.29%) 41.00 ( 16.33%) Success 1 Mean 51.00 ( 0.00%) 45.00 ( 11.76%) 42.60 ( 16.47%) Success 1 Max 55.00 ( 0.00%) 51.00 ( 7.27%) 46.00 ( 16.36%) Success 2 Min 53.00 ( 0.00%) 47.00 ( 11.32%) 44.00 ( 16.98%) Success 2 Mean 59.60 ( 0.00%) 50.80 ( 14.77%) 48.20 ( 19.13%) Success 2 Max 64.00 ( 0.00%) 56.00 ( 12.50%) 52.00 ( 18.75%) Success 3 Min 84.00 ( 0.00%) 82.00 ( 2.38%) 78.00 ( 7.14%) Success 3 Mean 85.60 ( 0.00%) 82.80 ( 3.27%) 79.40 ( 7.24%) Success 3 Max 86.00 ( 0.00%) 83.00 ( 3.49%) 80.00 ( 6.98%) Patch 1: 3.19-rc4 3.19-rc4 3.19-rc4 6-nothp-1 6-nothp-2 6-nothp-3 Success 1 Min 49.00 ( 0.00%) 44.00 ( 10.20%) 44.00 ( 10.20%) Success 1 Mean 51.80 ( 0.00%) 46.00 ( 11.20%) 45.80 ( 11.58%) Success 1 Max 54.00 ( 0.00%) 49.00 ( 9.26%) 49.00 ( 9.26%) Success 2 Min 58.00 ( 0.00%) 49.00 ( 15.52%) 48.00 ( 17.24%) Success 2 Mean 60.40 ( 0.00%) 51.80 ( 14.24%) 50.80 ( 15.89%) Success 2 Max 63.00 ( 0.00%) 54.00 ( 14.29%) 55.00 ( 12.70%) Success 3 Min 84.00 ( 0.00%) 81.00 ( 3.57%) 79.00 ( 5.95%) Success 3 Mean 85.00 ( 0.00%) 81.60 ( 4.00%) 79.80 ( 6.12%) Success 3 Max 86.00 ( 0.00%) 82.00 ( 4.65%) 82.00 ( 4.65%) Patch 2: 3.19-rc4 3.19-rc4 3.19-rc4 7-nothp-1 7-nothp-2 7-nothp-3 Success 1 Min 50.00 ( 0.00%) 44.00 ( 12.00%) 39.00 ( 22.00%) Success 1 Mean 52.80 ( 0.00%) 45.60 ( 13.64%) 42.40 ( 19.70%) Success 1 Max 55.00 ( 0.00%) 46.00 ( 16.36%) 47.00 ( 14.55%) Success 2 Min 52.00 ( 0.00%) 48.00 ( 7.69%) 45.00 ( 13.46%) Success 2 Mean 53.40 ( 0.00%) 49.80 ( 6.74%) 48.80 ( 8.61%) Success 2 Max 57.00 ( 0.00%) 52.00 ( 8.77%) 52.00 ( 8.77%) Success 3 Min 84.00 ( 0.00%) 81.00 ( 3.57%) 79.00 ( 5.95%) Success 3 Mean 85.00 ( 0.00%) 82.40 ( 3.06%) 79.60 ( 6.35%) Success 3 Max 86.00 ( 0.00%) 83.00 ( 3.49%) 80.00 ( 6.98%) Patch 3: 3.19-rc4 3.19-rc4 3.19-rc4 8-nothp-1 8-nothp-2 8-nothp-3 Success 1 Min 46.00 ( 0.00%) 44.00 ( 4.35%) 42.00 ( 8.70%) Success 1 Mean 50.20 ( 0.00%) 45.60 ( 9.16%) 44.00 ( 12.35%) Success 1 Max 52.00 ( 0.00%) 47.00 ( 9.62%) 47.00 ( 9.62%) Success 2 Min 53.00 ( 0.00%) 49.00 ( 7.55%) 48.00 ( 9.43%) Success 2 Mean 55.80 ( 0.00%) 50.60 ( 9.32%) 49.00 ( 12.19%) Success 2 Max 59.00 ( 0.00%) 52.00 ( 11.86%) 51.00 ( 13.56%) Success 3 Min 84.00 ( 0.00%) 80.00 ( 4.76%) 79.00 ( 5.95%) Success 3 Mean 85.40 ( 0.00%) 81.60 ( 4.45%) 80.40 ( 5.85%) Success 3 Max 87.00 ( 0.00%) 83.00 ( 4.60%) 82.00 ( 5.75%) While there's no improvement here, I consider reduced fragmentation events to be worth on its own. Patch 2 also seems to reduce scanning for free pages, and migrations in compaction, suggesting it has somewhat less work to do: Patch 1: Compaction stalls 4153 3959 3978 Compaction success 1523 1441 1446 Compaction failures 2630 2517 2531 Page migrate success 4600827 4943120 5104348 Page migrate failure 19763 16656 17806 Compaction pages isolated 9597640 10305617 10653541 Compaction migrate scanned 77828948 86533283 87137064 Compaction free scanned 517758295 521312840 521462251 Compaction cost 5503 5932 6110 Patch 2: Compaction stalls 3800 3450 3518 Compaction success 1421 1316 1317 Compaction failures 2379 2134 2201 Page migrate success 4160421 4502708 4752148 Page migrate failure 19705 14340 14911 Compaction pages isolated 8731983 9382374 9910043 Compaction migrate scanned 98362797 96349194 98609686 Compaction free scanned 496512560 469502017 480442545 Compaction cost 5173 5526 5811 As with v2, /proc/pagetypeinfo appears unaffected with respect to numbers of unmovable and reclaimable pageblocks. Configuring the benchmark to allocate like THP page fault (i.e. no sync compaction) gives much noisier results for iterations 2 and 3 after reboot. This is not so surprising given how [1] offers lower improvements in this scenario due to less restarts after deferred compaction which would change compaction pivot. Baseline: 3.19-rc4 3.19-rc4 3.19-rc4 5-thp-1 5-thp-2 5-thp-3 Page alloc extfrag event 8148965 6227815 6646741 Extfrag fragmenting 8147872 6227130 6646117 Extfrag fragmenting for unmovable 10324 12942 15975 Extfrag fragmenting unmovable placed with movable 5972 8495 10907 Extfrag fragmenting for reclaimable 601 1707 2210 Extfrag fragmenting reclaimable placed with movable 520 1570 2000 Extfrag fragmenting for movable 8136947 6212481 6627932 Patch 1: 3.19-rc4 3.19-rc4 3.19-rc4 6-thp-1 6-thp-2 6-thp-3 Page alloc extfrag event 8345457 7574471 7020419 Extfrag fragmenting 8343546 7573777 7019718 Extfrag fragmenting for unmovable 10256 18535 30716 Extfrag fragmenting unmovable placed with movable 6893 11726 22181 Extfrag fragmenting for reclaimable 465 1208 1023 Extfrag fragmenting reclaimable placed with movable 353 996 843 Extfrag fragmenting for movable 8332825 7554034 6987979 Patch 2: 3.19-rc4 3.19-rc4 3.19-rc4 7-thp-1 7-thp-2 7-thp-3 Page alloc extfrag event 3512847 3020756 2891625 Extfrag fragmenting 3511940 3020185 2891059 Extfrag fragmenting for unmovable 9017 6892 6191 Extfrag fragmenting unmovable placed with movable 1524 3053 2435 Extfrag fragmenting for reclaimable 445 1081 1160 Extfrag fragmenting reclaimable placed with movable 375 918 986 Extfrag fragmenting for movable 3502478 3012212 2883708 Patch 3: 3.19-rc4 3.19-rc4 3.19-rc4 8-thp-1 8-thp-2 8-thp-3 Page alloc extfrag event 3181699 3082881 2674164 Extfrag fragmenting 3180812 3082303 2673611 Extfrag fragmenting for unmovable 1201 4031 4040 Extfrag fragmenting unmovable placed with movable 974 3611 3645 Extfrag fragmenting for reclaimable 478 1165 1294 Extfrag fragmenting reclaimable placed with movable 387 985 1030 Extfrag fragmenting for movable 3179133 3077107 2668277 The improvements for first iteration are clear, the rest is much noisier and can appear like regression for Patch 1. Anyway, patch 2 rectifies it. Allocation success rates are again unaffected so there's no point in making this e-mail any longer. [1] http://marc.info/?l=linux-mm&m=142166196321125&w=2 This patch (of 3): When __rmqueue_fallback() is called to allocate a page of order X, it will find a page of order Y >= X of a fallback migratetype, which is different from the desired migratetype. With the help of try_to_steal_freepages(), it may change the migratetype (to the desired one) also of: 1) all currently free pages in the pageblock containing the fallback page 2) the fallback pageblock itself 3) buddy pages created by splitting the fallback page (when Y > X) These decisions take the order Y into account, as well as the desired migratetype, with the goal of preventing multiple fallback allocations that could e.g. distribute UNMOVABLE allocations among multiple pageblocks. Originally, decision for 1) has implied the decision for 3). Commit 47118af076f6 ("mm: mmzone: MIGRATE_CMA migration type added") changed that (probably unintentionally) so that the buddy pages in case 3) are always changed to the desired migratetype, except for CMA pageblocks. Commit fef903efcf0c ("mm/page_allo.c: restructure free-page stealing code and fix a bug") did some refactoring and added a comment that the case of 3) is intended. Commit 0cbef29a7821 ("mm: __rmqueue_fallback() should respect pageblock type") removed the comment and tried to restore the original behavior where 1) implies 3), but due to the previous refactoring, the result is instead that only 2) implies 3) - and the conditions for 2) are less frequently met than conditions for 1). This may increase fragmentation in situations where the code decides to steal all free pages from the pageblock (case 1)), but then gives back the buddy pages produced by splitting. This patch restores the original intended logic where 1) implies 3). During testing with stress-highalloc from mmtests, this has shown to decrease the number of events where UNMOVABLE and RECLAIMABLE allocations steal from MOVABLE pageblocks, which can lead to permanent fragmentation. In some cases it has increased the number of events when MOVABLE allocations steal from UNMOVABLE or RECLAIMABLE pageblocks, but these are fixable by sync compaction and thus less harmful. Note that evaluation has shown that the behavior introduced by 47118af076f6 for buddy pages in case 3) is actually even better than the original logic, so the following patch will introduce it properly once again. For stable backports of this patch it makes thus sense to only fix versions containing 0cbef29a7821. [iamjoonsoo.kim@lge.com: tracepoint fix] Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: <stable@vger.kernel.org> [3.13+ containing 0cbef29a7821] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* oom, PM: make OOM detection in the freezer path racelessMichal Hocko2015-02-111-15/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 5695be142e20 ("OOM, PM: OOM killed task shouldn't escape PM suspend") has left a race window when OOM killer manages to note_oom_kill after freeze_processes checks the counter. The race window is quite small and really unlikely and partial solution deemed sufficient at the time of submission. Tejun wasn't happy about this partial solution though and insisted on a full solution. That requires the full OOM and freezer's task freezing exclusion, though. This is done by this patch which introduces oom_sem RW lock and turns oom_killer_disable() into a full OOM barrier. oom_killer_disabled check is moved from the allocation path to the OOM level and we take oom_sem for reading for both the check and the whole OOM invocation. oom_killer_disable() takes oom_sem for writing so it waits for all currently running OOM killer invocations. Then it disable all the further OOMs by setting oom_killer_disabled and checks for any oom victims. Victims are counted via mark_tsk_oom_victim resp. unmark_oom_victim. The last victim wakes up all waiters enqueued by oom_killer_disable(). Therefore this function acts as the full OOM barrier. The page fault path is covered now as well although it was assumed to be safe before. As per Tejun, "We used to have freezing points deep in file system code which may be reacheable from page fault." so it would be better and more robust to not rely on freezing points here. Same applies to the memcg OOM killer. out_of_memory tells the caller whether the OOM was allowed to trigger and the callers are supposed to handle the situation. The page allocation path simply fails the allocation same as before. The page fault path will retry the fault (more on that later) and Sysrq OOM trigger will simply complain to the log. Normally there wouldn't be any unfrozen user tasks after try_to_freeze_tasks so the function will not block. But if there was an OOM killer racing with try_to_freeze_tasks and the OOM victim didn't finish yet then we have to wait for it. This should complete in a finite time, though, because - the victim cannot loop in the page fault handler (it would die on the way out from the exception) - it cannot loop in the page allocator because all the further allocation would fail and __GFP_NOFAIL allocations are not acceptable at this stage - it shouldn't be blocked on any locks held by frozen tasks (try_to_freeze expects lockless context) and kernel threads and work queues are not frozen yet Signed-off-by: Michal Hocko <mhocko@suse.cz> Suggested-by: Tejun Heo <tj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: use correct format specifiers when printing address rangesJuergen Gross2015-02-111-9/+11
| | | | | | | | | | Especially on 32 bit kernels memory node ranges are printed with 32 bit wide addresses only. Use u64 types and %llx specifiers to print full width of addresses. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: more checks on free_pages_prepare() for tail pagesKirill A. Shutemov2015-02-111-4/+23
| | | | | | | | | | | | | | | Although it was not called, destroy_compound_page() did some potentially useful checks. Let's re-introduce them in free_pages_prepare(), where they can be actually triggered when CONFIG_DEBUG_VM=y. compound_order() assert is already in free_pages_prepare(). We have few checks for tail pages left. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/page_alloc.c: drop dead destroy_compound_page()Kirill A. Shutemov2015-02-111-34/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The only caller is __free_one_page(). By the time we should have page->flags to be cleared already: - for 0-order pages though PCP list: free_hot_cold_page() free_pages_prepare() free_pages_check() page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; <put the page to PCP list> free_pcppages_bulk() page = <withdraw pages from PCP list> __free_one_page(page) - for non-0-order pages: __free_pages_ok() free_pages_prepare() free_pages_check() page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; free_one_page() __free_one_page() So there's no way PageCompound() will return true in __free_one_page(). Let's remove dead destroy_compound_page() and put assert for page->flags there instead. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: reduce try_to_compact_pages parametersVlastimil Babka2015-02-111-25/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Expand the usage of the struct alloc_context introduced in the previous patch also for calling try_to_compact_pages(), to reduce the number of its parameters. Since the function is in different compilation unit, we need to move alloc_context definition in the shared mm/internal.h header. With this change we get simpler code and small savings of code size and stack usage: add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-27 (-27) function old new delta __alloc_pages_direct_compact 283 256 -27 add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-13 (-13) function old new delta try_to_compact_pages 582 569 -13 Stack usage of __alloc_pages_direct_compact goes from 24 to none (per scripts/checkstack.pl). Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Minchan Kim <minchan@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, page_alloc: reduce number of alloc_pages* functions' parametersVlastimil Babka2015-02-111-121/+108
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce struct alloc_context to accumulate the numerous parameters passed between the alloc_pages* family of functions and get_page_from_freelist(). This excludes gfp_flags and alloc_info, which mutate too much along the way, and allocation order, which is conceptually different. The result is shorter function signatures, as well as overal code size and stack usage reductions. bloat-o-meter: add/remove: 0/0 grow/shrink: 1/2 up/down: 127/-310 (-183) function old new delta get_page_from_freelist 2525 2652 +127 __alloc_pages_direct_compact 329 283 -46 __alloc_pages_nodemask 2564 2300 -264 checkstack.pl: function old new __alloc_pages_nodemask 248 200 get_page_from_freelist 168 184 __alloc_pages_direct_compact 40 24 Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Minchan Kim <minchan@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: set page->pfmemalloc in prep_new_page()Vlastimil Babka2015-02-111-21/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The possibility of replacing the numerous parameters of alloc_pages* functions with a single structure has been discussed when Minchan proposed to expand the x86 kernel stack [1]. This series implements the change, along with few more cleanups/microoptimizations. The series is based on next-20150108 and I used gcc 4.8.3 20140627 on openSUSE 13.2 for compiling. Config includess NUMA and COMPACTION. The core change is the introduction of a new struct alloc_context, which looks like this: struct alloc_context { struct zonelist *zonelist; nodemask_t *nodemask; struct zone *preferred_zone; int classzone_idx; int migratetype; enum zone_type high_zoneidx; }; All the contents is mostly constant, except that __alloc_pages_slowpath() changes preferred_zone, classzone_idx and potentially zonelist. But that's not a problem in case control returns to retry_cpuset: in __alloc_pages_nodemask(), those will be reset to initial values again (although it's a bit subtle). On the other hand, gfp_flags and alloc_info mutate so much that it doesn't make sense to put them into alloc_context. Still, the result is one parameter instead of up to 7. This is all in Patch 2. Patch 3 is a step to expand alloc_context usage out of page_alloc.c itself. The function try_to_compact_pages() can also much benefit from the parameter reduction, but it means the struct definition has to be moved to a shared header. Patch 1 should IMHO be included even if the rest is deemed not useful enough. It improves maintainability and also has some code/stack reduction. Patch 4 is OTOH a tiny optimization. Overall bloat-o-meter results: add/remove: 0/0 grow/shrink: 0/4 up/down: 0/-460 (-460) function old new delta nr_free_zone_pages 129 115 -14 __alloc_pages_direct_compact 329 256 -73 get_page_from_freelist 2670 2576 -94 __alloc_pages_nodemask 2564 2285 -279 try_to_compact_pages 582 579 -3 Overall stack sizes per ./scripts/checkstack.pl: old new delta get_page_from_freelist: 184 184 0 __alloc_pages_nodemask 248 200 -48 __alloc_pages_direct_c 40 - -40 try_to_compact_pages 72 72 0 -88 [1] http://marc.info/?l=linux-mm&m=140142462528257&w=2 This patch (of 4): prep_new_page() sets almost everything in the struct page of the page being allocated, except page->pfmemalloc. This is not obvious and has at least once led to a bug where page->pfmemalloc was forgotten to be set correctly, see commit 8fb74b9fb2b1 ("mm: compaction: partially revert capture of suitable high-order page"). This patch moves the pfmemalloc setting to prep_new_page(), which means it needs to gain alloc_flags parameter. The call to prep_new_page is moved from buffered_rmqueue() to get_page_from_freelist(), which also leads to simpler code. An obsolete comment for buffered_rmqueue() is replaced. In addition to better maintainability there is a small reduction of code and stack usage for get_page_from_freelist(), which inlines the other functions involved. add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-145 (-145) function old new delta get_page_from_freelist 2670 2525 -145 Stack usage is reduced from 184 to 168 bytes. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Minchan Kim <minchan@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kmemcheck: move hook into __alloc_pages_nodemask() for the page allocatorXishi Qiu2015-02-111-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Now kmemcheck_pagealloc_alloc() is only called by __alloc_pages_slowpath(). __alloc_pages_nodemask() __alloc_pages_slowpath() kmemcheck_pagealloc_alloc() And the page will not be tracked by kmemcheck in the following path. __alloc_pages_nodemask() get_page_from_freelist() So move kmemcheck_pagealloc_alloc() into __alloc_pages_nodemask(), like this: __alloc_pages_nodemask() ... get_page_from_freelist() if (!page) __alloc_pages_slowpath() kmemcheck_pagealloc_alloc() ... Signed-off-by: Xishi Qiu <qiuxishi@huawei.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/page_alloc.c:__alloc_pages_nodemask(): don't alter arg gfp_maskAndrew Morton2015-02-111-6/+9
| | | | | | | | | | | | | | | | | | | __alloc_pages_nodemask() strips __GFP_IO when retrying the page allocation. But it does this by altering the function-wide variable gfp_mask. This will cause subsequent allocation attempts to inadvertently use the modified gfp_mask. Also, pass the correct mask (the mask we actually used) into trace_mm_page_alloc(). Cc: Ming Lei <ming.lei@canonical.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/page_alloc.c: place zone_id check before VM_BUG_ON_PAGE checkWeijie Yang2015-02-101-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the freeing page and its buddy page are not at the same zone, the current holding zone->lock for the freeing page cann't prevent buddy page getting allocated, this could trigger VM_BUG_ON_PAGE in page_is_buddy() at a very tiny chance, such as: cpu 0: cpu 1: hold zone_1 lock check page and it buddy PageBuddy(buddy) is true hold zone_2 lock page_order(buddy) == order is true alloc buddy trigger VM_BUG_ON_PAGE(page_count(buddy) != 0) zone_1->lock prevents the freeing page getting allocated zone_2->lock prevents the buddy page getting allocated they are not the same zone->lock. If we can't remove the zone_id check statement, it's better handle this rare race. This patch fixes this by placing the zone_id check before the VM_BUG_ON_PAGE check. Signed-off-by: Weijie Yang <weijie.yang@samsung.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: page_alloc: embed OOM killing naturally into allocation slowpathJohannes Weiner2015-01-261-47/+35
| | | | | | | | | | | | | | | | | | | | | | | The OOM killing invocation does a lot of duplicative checks against the task's allocation context. Rework it to take advantage of the existing checks in the allocator slowpath. The OOM killer is invoked when the allocator is unable to reclaim any pages but the allocation has to keep looping. Instead of having a check for __GFP_NORETRY hidden in oom_gfp_allowed(), just move the OOM invocation to the true branch of should_alloc_retry(). The __GFP_FS check from oom_gfp_allowed() can then be moved into the OOM avoidance branch in __alloc_pages_may_oom(), along with the PF_DUMPCORE test. __alloc_pages_may_oom() can then signal to the caller whether the OOM killer was invoked, instead of requiring it to duplicate the order and high_zoneidx checks to guess this when deciding whether to continue. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: cma: split cma-reserved in dmesg logPintu Kumar2014-12-181-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the system boots up, in the dmesg logs we can see the memory statistics along with total reserved as below. Memory: 458840k/458840k available, 65448k reserved, 0K highmem When CMA is enabled, still the total reserved memory remains the same. However, the CMA memory is not considered as reserved. But, when we see /proc/meminfo, the CMA memory is part of free memory. This creates confusion. This patch corrects the problem by properly subtracting the CMA reserved memory from the total reserved memory in dmesg logs. Below is the dmesg snapshot from an arm based device with 512MB RAM and 12MB single CMA region. Before this change: Memory: 458840k/458840k available, 65448k reserved, 0K highmem After this change: Memory: 458840k/458840k available, 53160k reserved, 12288k cma-reserved, 0K highmem Signed-off-by: Pintu Kumar <pintu.k@samsung.com> Signed-off-by: Vishnu Pratap Singh <vishnu.ps@samsung.com> Acked-by: Michal Nazarewicz <mina86@mina86.com> Cc: Rafael Aquini <aquini@redhat.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: remove the highmem zones' memmap in the highmem zoneZhong Hongbo2014-12-131-10/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | Since 01cefaef40c4 ("mm: provide more accurate estimation of pages occupied by memmap") allocate the pages from lowmem for the highmem zones' memmap. So It is not need to reserver the memmap's for the highmem. A 2G DDR3 for the arm platform: On node 0 totalpages: 524288 free_area_init_node: node 0, pgdat 80ccd380, node_mem_map 80d38000 DMA zone: 3568 pages used for memmap DMA zone: 0 pages reserved DMA zone: 456704 pages, LIFO batch:31 HighMem zone: 528 pages used for memmap HighMem zone: 67584 pages, LIFO batch:15 On node 0 totalpages: 524288 free_area_init_node: node 0, pgdat 80cd6f40, node_mem_map 80d42000 DMA zone: 3568 pages used for memmap DMA zone: 0 pages reserved DMA zone: 456704 pages, LIFO batch:31 HighMem zone: 67584 pages, LIFO batch:15 Signed-off-by: Hongbo Zhong <hongbo.zhong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: vmscan: invoke slab shrinkers from shrink_zone()Johannes Weiner2014-12-131-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The slab shrinkers are currently invoked from the zonelist walkers in kswapd, direct reclaim, and zone reclaim, all of which roughly gauge the eligible LRU pages and assemble a nodemask to pass to NUMA-aware shrinkers, which then again have to walk over the nodemask. This is redundant code, extra runtime work, and fairly inaccurate when it comes to the estimation of actually scannable LRU pages. The code duplication will only get worse when making the shrinkers cgroup-aware and requiring them to have out-of-band cgroup hierarchy walks as well. Instead, invoke the shrinkers from shrink_zone(), which is where all reclaimers end up, to avoid this duplication. Take the count for eligible LRU pages out of get_scan_count(), which considers many more factors than just the availability of swap space, like zone_reclaimable_pages() currently does. Accumulate the number over all visited lruvecs to get the per-zone value. Some nodes have multiple zones due to memory addressing restrictions. To avoid putting too much pressure on the shrinkers, only invoke them once for each such node, using the class zone of the allocation as the pivot zone. For now, this integrates the slab shrinking better into the reclaim logic and gets rid of duplicative invocations from kswapd, direct reclaim, and zone reclaim. It also prepares for cgroup-awareness, allowing memcg-capable shrinkers to be added at the lruvec level without much duplication of both code and runtime work. This changes kswapd behavior, which used to invoke the shrinkers for each zone, but with scan ratios gathered from the entire node, resulting in meaningless pressure quantities on multi-zone nodes. Zone reclaim behavior also changes. It used to shrink slabs until the same amount of pages were shrunk as were reclaimed from the LRUs. Now it merely invokes the shrinkers once with the zone's scan ratio, which makes the shrinkers go easier on caches that implement aging and would prefer feeding back pressure from recently used slab objects to unused LRU pages. [vdavydov@parallels.com: assure class zone is populated] Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/page_owner: keep track of page ownersJoonsoo Kim2014-12-131-1/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is the page owner tracking code which is introduced so far ago. It is resident on Andrew's tree, though, nobody tried to upstream so it remain as is. Our company uses this feature actively to debug memory leak or to find a memory hogger so I decide to upstream this feature. This functionality help us to know who allocates the page. When allocating a page, we store some information about allocation in extra memory. Later, if we need to know status of all pages, we can get and analyze it from this stored information. In previous version of this feature, extra memory is statically defined in struct page, but, in this version, extra memory is allocated outside of struct page. It enables us to turn on/off this feature at boottime without considerable memory waste. Although we already have tracepoint for tracing page allocation/free, using it to analyze page owner is rather complex. We need to enlarge the trace buffer for preventing overlapping until userspace program launched. And, launched program continually dump out the trace buffer for later analysis and it would change system behaviour with more possibility rather than just keeping it in memory, so bad for debug. Moreover, we can use page_owner feature further for various purposes. For example, we can use it for fragmentation statistics implemented in this patch. And, I also plan to implement some CMA failure debugging feature using this interface. I'd like to give the credit for all developers contributed this feature, but, it's not easy because I don't know exact history. Sorry about that. Below is people who has "Signed-off-by" in the patches in Andrew's tree. Contributor: Alexander Nyberg <alexn@dsv.su.se> Mel Gorman <mgorman@suse.de> Dave Hansen <dave@linux.vnet.ibm.com> Minchan Kim <minchan@kernel.org> Michal Nazarewicz <mina86@mina86.com> Andrew Morton <akpm@linux-foundation.org> Jungsoo Son <jungsoo.son@lge.com> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Dave Hansen <dave@sr71.net> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Jungsoo Son <jungsoo.son@lge.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug-pagealloc: make debug-pagealloc boottime configurableJoonsoo Kim2014-12-131-0/+20
| | | | | | | | | | | | | | | | | | | | | | Now, we have prepared to avoid using debug-pagealloc in boottime. So introduce new kernel-parameter to disable debug-pagealloc in boottime, and makes related functions to be disabled in this case. Only non-intuitive part is change of guard page functions. Because guard page is effective only if debug-pagealloc is enabled, turning off according to debug-pagealloc is reasonable thing to do. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Dave Hansen <dave@sr71.net> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Jungsoo Son <jungsoo.son@lge.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug-pagealloc: prepare boottime configurable on/offJoonsoo Kim2014-12-131-3/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Until now, debug-pagealloc needs extra flags in struct page, so we need to recompile whole source code when we decide to use it. This is really painful, because it takes some time to recompile and sometimes rebuild is not possible due to third party module depending on struct page. So, we can't use this good feature in many cases. Now, we have the page extension feature that allows us to insert extra flags to outside of struct page. This gets rid of third party module issue mentioned above. And, this allows us to determine if we need extra memory for this page extension in boottime. With these property, we can avoid using debug-pagealloc in boottime with low computational overhead in the kernel built with CONFIG_DEBUG_PAGEALLOC. This will help our development process greatly. This patch is the preparation step to achive above goal. debug-pagealloc originally uses extra field of struct page, but, after this patch, it will use field of struct page_ext. Because memory for page_ext is allocated later than initialization of page allocator in CONFIG_SPARSEMEM, we should disable debug-pagealloc feature temporarily until initialization of page_ext. This patch implements this. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Dave Hansen <dave@sr71.net> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Jungsoo Son <jungsoo.son@lge.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/page_ext: resurrect struct page extending code for debuggingJoonsoo Kim2014-12-131-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we debug something, we'd like to insert some information to every page. For this purpose, we sometimes modify struct page itself. But, this has drawbacks. First, it requires re-compile. This makes us hesitate to use the powerful debug feature so development process is slowed down. And, second, sometimes it is impossible to rebuild the kernel due to third party module dependency. At third, system behaviour would be largely different after re-compile, because it changes size of struct page greatly and this structure is accessed by every part of kernel. Keeping this as it is would be better to reproduce errornous situation. This feature is intended to overcome above mentioned problems. This feature allocates memory for extended data per page in certain place rather than the struct page itself. This memory can be accessed by the accessor functions provided by this code. During the boot process, it checks whether allocation of huge chunk of memory is needed or not. If not, it avoids allocating memory at all. With this advantage, we can include this feature into the kernel in default and can avoid rebuild and solve related problems. Until now, memcg uses this technique. But, now, memcg decides to embed their variable to struct page itself and it's code to extend struct page has been removed. I'd like to use this code to develop debug feature, so this patch resurrect it. To help these things to work well, this patch introduces two callbacks for clients. One is the need callback which is mandatory if user wants to avoid useless memory allocation at boot-time. The other is optional, init callback, which is used to do proper initialization after memory is allocated. Detailed explanation about purpose of these functions is in code comment. Please refer it. Others are completely same with previous extension code in memcg. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Dave Hansen <dave@sr71.net> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Jungsoo Son <jungsoo.son@lge.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug-pagealloc: cleanup page guard codeJoonsoo Kim2014-12-131-19/+19
| | | | | | | | | | | | | | Page guard is used by debug-pagealloc feature. Currently, it is open-coded, but, I think that more abstraction of it makes core page allocator code more readable. There is no functional difference. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Gioh Kim <gioh.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-3.19' of ↵Linus Torvalds2014-12-111-3/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup update from Tejun Heo: "cpuset got simplified a bit. cgroup core got a fix on unified hierarchy and grew some effective css related interfaces which will be used for blkio support for writeback IO traffic which is currently being worked on" * 'for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: implement cgroup_get_e_css() cgroup: add cgroup_subsys->css_e_css_changed() cgroup: add cgroup_subsys->css_released() cgroup: fix the async css offline wait logic in cgroup_subtree_control_write() cgroup: restructure child_subsys_mask handling in cgroup_subtree_control_write() cgroup: separate out cgroup_calc_child_subsys_mask() from cgroup_refresh_child_subsys_mask() cpuset: lock vs unlock typo cpuset: simplify cpuset_node_allowed API cpuset: convert callback_mutex to a spinlock
| * cpuset: simplify cpuset_node_allowed APIVladimir Davydov2014-10-271-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Current cpuset API for checking if a zone/node is allowed to allocate from looks rather awkward. We have hardwall and softwall versions of cpuset_node_allowed with the softwall version doing literally the same as the hardwall version if __GFP_HARDWALL is passed to it in gfp flags. If it isn't, the softwall version may check the given node against the enclosing hardwall cpuset, which it needs to take the callback lock to do. Such a distinction was introduced by commit 02a0e53d8227 ("cpuset: rework cpuset_zone_allowed api"). Before, we had the only version with the __GFP_HARDWALL flag determining its behavior. The purpose of the commit was to avoid sleep-in-atomic bugs when someone would mistakenly call the function without the __GFP_HARDWALL flag for an atomic allocation. The suffixes introduced were intended to make the callers think before using the function. However, since the callback lock was converted from mutex to spinlock by the previous patch, the softwall check function cannot sleep, and these precautions are no longer necessary. So let's simplify the API back to the single check. Suggested-by: David Rientjes <rientjes@google.com> Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Acked-by: Christoph Lameter <cl@linux.com> Acked-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | mm: move page->mem_cgroup bad page handling into generic codeJohannes Weiner2014-12-101-4/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that the external page_cgroup data structure and its lookup is gone, let the generic bad_page() check for page->mem_cgroup sanity. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Vladimir Davydov <vdavydov@parallels.com> Acked-by: David S. Miller <davem@davemloft.net> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Tejun Heo <tj@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: embed the memcg pointer directly into struct pageJohannes Weiner2014-12-101-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Memory cgroups used to have 5 per-page pointers. To allow users to disable that amount of overhead during runtime, those pointers were allocated in a separate array, with a translation layer between them and struct page. There is now only one page pointer remaining: the memcg pointer, that indicates which cgroup the page is associated with when charged. The complexity of runtime allocation and the runtime translation overhead is no longer justified to save that *potential* 0.19% of memory. With CONFIG_SLUB, page->mem_cgroup actually sits in the doubleword padding after the page->private member and doesn't even increase struct page, and then this patch actually saves space. Remaining users that care can still compile their kernels without CONFIG_MEMCG. text data bss dec hex filename 8828345 1725264 983040 11536649 b00909 vmlinux.old 8827425 1725264 966656 11519345 afc571 vmlinux.new [mhocko@suse.cz: update Documentation/cgroups/memory.txt] Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Vladimir Davydov <vdavydov@parallels.com> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Michal Hocko <mhocko@suse.cz> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: Tejun Heo <tj@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: fix a spelling mistakeWei Yuan2014-12-101-1/+1
| | | | | | | | | | | | | | Signed-off-by Wei Yuan <weiyuan.wei@huawei.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm, compaction: more focused lru and pcplists drainingVlastimil Babka2014-12-101-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The goal of memory compaction is to create high-order freepages through page migration. Page migration however puts pages on the per-cpu lru_add cache, which is later flushed to per-cpu pcplists, and only after pcplists are drained the pages can actually merge. This can happen due to the per-cpu caches becoming full through further freeing, or explicitly. During direct compaction, it is useful to do the draining explicitly so that pages merge as soon as possible and compaction can detect success immediately and keep the latency impact at minimum. However the current implementation is far from ideal. Draining is done only in __alloc_pages_direct_compact(), after all zones were already compacted, and the decisions to continue or stop compaction in individual zones was done without the last batch of migrations being merged. It is also missing the draining of lru_add cache before the pcplists. This patch moves the draining for direct compaction into compact_zone(). It adds the missing lru_cache draining and uses the newly introduced single zone pcplists draining to reduce overhead and avoid impact on unrelated zones. Draining is only performed when it can actually lead to merging of a page of desired order (passed by cc->order). This means it is only done when migration occurred in the previously scanned cc->order aligned block(s) and the migration scanner is now pointing to the next cc->order aligned block. The patch has been tested with stress-highalloc benchmark from mmtests. Although overal allocation success rates of the benchmark were not affected, the number of detected compaction successes has doubled. This suggests that allocations were previously successful due to implicit merging caused by background activity, making a later allocation attempt succeed immediately, but not attributing the success to compaction. Since stress-highalloc always tries to allocate almost the whole memory, it cannot show the improvement in its reported success rate metric. However after this patch, compaction should detect success and terminate earlier, reducing the direct compaction latencies in a real scenario. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Minchan Kim <minchan@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Christoph Lameter <cl@linux.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm, compaction: simplify deferred compactionVlastimil Babka2014-12-101-11/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since commit 53853e2d2bfb ("mm, compaction: defer each zone individually instead of preferred zone"), compaction is deferred for each zone where sync direct compaction fails, and reset where it succeeds. However, it was observed that for DMA zone compaction often appeared to succeed while subsequent allocation attempt would not, due to different outcome of watermark check. In order to properly defer compaction in this zone, the candidate zone has to be passed back to __alloc_pages_direct_compact() and compaction deferred in the zone after the allocation attempt fails. The large source of mismatch between watermark check in compaction and allocation was the lack of alloc_flags and classzone_idx values in compaction, which has been fixed in the previous patch. So with this problem fixed, we can simplify the code by removing the candidate_zone parameter and deferring in __alloc_pages_direct_compact(). After this patch, the compaction activity during stress-highalloc benchmark is still somewhat increased, but it's negligible compared to the increase that occurred without the better watermark checking. This suggests that it is still possible to apparently succeed in compaction but fail to allocate, possibly due to parallel allocation activity. [akpm@linux-foundation.org: fix build] Suggested-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Minchan Kim <minchan@kernel.org> Cc: Mel Gorman <mgorman@suse.de> 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: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm, compaction: pass classzone_idx and alloc_flags to watermark checkingVlastimil Babka2014-12-101-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Compaction relies on zone watermark checks for decisions such as if it's worth to start compacting in compaction_suitable() or whether compaction should stop in compact_finished(). The watermark checks take classzone_idx and alloc_flags parameters, which are related to the memory allocation request. But from the context of compaction they are currently passed as 0, including the direct compaction which is invoked to satisfy the allocation request, and could therefore know the proper values. The lack of proper values can lead to mismatch between decisions taken during compaction and decisions related to the allocation request. Lack of proper classzone_idx value means that lowmem_reserve is not taken into account. This has manifested (during recent changes to deferred compaction) when DMA zone was used as fallback for preferred Normal zone. compaction_suitable() without proper classzone_idx would think that the watermarks are already satisfied, but watermark check in get_page_from_freelist() would fail. Because of this problem, deferring compaction has extra complexity that can be removed in the following patch. The issue (not confirmed in practice) with missing alloc_flags is opposite in nature. For allocations that include ALLOC_HIGH, ALLOC_HIGHER or ALLOC_CMA in alloc_flags (the last includes all MOVABLE allocations on CMA-enabled systems) the watermark checking in compaction with 0 passed will be stricter than in get_page_from_freelist(). In these cases compaction might be running for a longer time than is really needed. Another issue compaction_suitable() is that the check for "does the zone need compaction at all?" comes only after the check "does the zone have enough free free pages to succeed compaction". The latter considers extra pages for migration and can therefore in some situations fail and return COMPACT_SKIPPED, although the high-order allocation would succeed and we should return COMPACT_PARTIAL. This patch fixes these problems by adding alloc_flags and classzone_idx to struct compact_control and related functions involved in direct compaction and watermark checking. Where possible, all other callers of compaction_suitable() pass proper values where those are known. This is currently limited to classzone_idx, which is sometimes known in kswapd context. However, the direct reclaim callers should_continue_reclaim() and compaction_ready() do not currently know the proper values, so the coordination between reclaim and compaction may still not be as accurate as it could. This can be fixed later, if it's shown to be an issue. Additionaly the checks in compact_suitable() are reordered to address the second issue described above. The effect of this patch should be slightly better high-order allocation success rates and/or less compaction overhead, depending on the type of allocations and presence of CMA. It allows simplifying deferred compaction code in a followup patch. When testing with stress-highalloc, there was some slight improvement (which might be just due to variance) in success rates of non-THP-like allocations. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Minchan Kim <minchan@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Christoph Lameter <cl@linux.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: verify compound order when freeing a pageYu Zhao2014-12-101-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This allows us to catch the bug fixed in the previous patch (mm: free compound page with correct order). Here we also verify whether a page is tail page or not -- tail pages are supposed to be freed along with their head, not by themselves. Signed-off-by: Yu Zhao <yuzhao@google.com> Reviewed-by: "Kirill A. Shutemov" <kirill@shutemov.name> 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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm, cma: drain single zone pcplistsVlastimil Babka2014-12-101-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CMA allocation drains pcplists so that pages can merge back to buddy allocator. Since it operates on a single zone, we can reduce the pcplists drain to the single zone, which is now possible. The change should make CMA allocations faster and not disturbing unrelated pcplists anymore. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: introduce single zone pcplists drainVlastimil Babka2014-12-101-25/+56
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The functions for draining per-cpu pages back to buddy allocators currently always operate on all zones. There are however several cases where the drain is only needed in the context of a single zone, and spilling other pcplists is a waste of time both due to the extra spilling and later refilling. This patch introduces new zone pointer parameter to drain_all_pages() and changes the dummy parameter of drain_local_pages() to be also a zone pointer. When NULL is passed, the functions operate on all zones as usual. Passing a specific zone pointer reduces the work to the single zone. All callers are updated to pass the NULL pointer in this patch. Conversion to single zone (where appropriate) is done in further patches. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm/page_alloc.c: convert boot printks without log level to pr_infoAnton Blanchard2014-12-101-11/+11
| | | | | | | | | | | | Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm/debug-pagealloc: correct freepage accounting and order resettingJoonsoo Kim2014-11-131-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Gioh Kim <gioh.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: alloc_contig_range: demote pages busy message from warn to infoMichal Nazarewicz2014-11-131-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: Michal 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm/page_alloc: restrict max order of merging on isolated pageblockJoonsoo Kim2014-11-131-27/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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