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79 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Mel Gorman
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8fb74b9fb2 |
mm: compaction: partially revert capture of suitable high-order page
Eric Wong reported on 3.7 and 3.8-rc2 that ppoll() got stuck when waiting for POLLIN on a local TCP socket. It was easier to trigger if there was disk IO and dirty pages at the same time and he bisected it to commit |
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Jason Liu
|
7964c06d66 |
mm: compaction: fix echo 1 > compact_memory return error issue
when run the folloing command under shell, it will return error sh/$ echo 1 > /proc/sys/vm/compact_memory sh/$ sh: write error: Bad address After strace, I found the following log: ... write(1, "1\n", 2) = 3 write(1, "", 4294967295) = -1 EFAULT (Bad address) write(2, "echo: write error: Bad address\n", 31echo: write error: Bad address ) = 31 This tells system return 3(COMPACT_COMPLETE) after write data to compact_memory. The fix is to make the system just return 0 instead 3(COMPACT_COMPLETE) from sysctl_compaction_handler after compaction_nodes finished. Signed-off-by: Jason Liu <r64343@freescale.com> Suggested-by: David Rientjes <rientjes@google.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: David Rientjes <rientjes@google.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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Minchan Kim
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010fc29a45 |
compaction: fix build error in CMA && !COMPACTION
isolate_freepages_block() and isolate_migratepages_range() are used for
CMA as well as compaction so it breaks build for CONFIG_CMA &&
!CONFIG_COMPACTION.
This patch fixes it.
[akpm@linux-foundation.org: add "do { } while (0)", per Mel]
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
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>
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Linus Torvalds
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3d59eebc5e |
Automatic NUMA Balancing V11
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Merge tag 'balancenuma-v11' of git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux-balancenuma
Pull Automatic NUMA Balancing bare-bones from Mel Gorman:
"There are three implementations for NUMA balancing, this tree
(balancenuma), numacore which has been developed in tip/master and
autonuma which is in aa.git.
In almost all respects balancenuma is the dumbest of the three because
its main impact is on the VM side with no attempt to be smart about
scheduling. In the interest of getting the ball rolling, it would be
desirable to see this much merged for 3.8 with the view to building
scheduler smarts on top and adapting the VM where required for 3.9.
The most recent set of comparisons available from different people are
mel: https://lkml.org/lkml/2012/12/9/108
mingo: https://lkml.org/lkml/2012/12/7/331
tglx: https://lkml.org/lkml/2012/12/10/437
srikar: https://lkml.org/lkml/2012/12/10/397
The results are a mixed bag. In my own tests, balancenuma does
reasonably well. It's dumb as rocks and does not regress against
mainline. On the other hand, Ingo's tests shows that balancenuma is
incapable of converging for this workloads driven by perf which is bad
but is potentially explained by the lack of scheduler smarts. Thomas'
results show balancenuma improves on mainline but falls far short of
numacore or autonuma. Srikar's results indicate we all suffer on a
large machine with imbalanced node sizes.
My own testing showed that recent numacore results have improved
dramatically, particularly in the last week but not universally.
We've butted heads heavily on system CPU usage and high levels of
migration even when it shows that overall performance is better.
There are also cases where it regresses. Of interest is that for
specjbb in some configurations it will regress for lower numbers of
warehouses and show gains for higher numbers which is not reported by
the tool by default and sometimes missed in treports. Recently I
reported for numacore that the JVM was crashing with
NullPointerExceptions but currently it's unclear what the source of
this problem is. Initially I thought it was in how numacore batch
handles PTEs but I'm no longer think this is the case. It's possible
numacore is just able to trigger it due to higher rates of migration.
These reports were quite late in the cycle so I/we would like to start
with this tree as it contains much of the code we can agree on and has
not changed significantly over the last 2-3 weeks."
* tag 'balancenuma-v11' of git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux-balancenuma: (50 commits)
mm/rmap, migration: Make rmap_walk_anon() and try_to_unmap_anon() more scalable
mm/rmap: Convert the struct anon_vma::mutex to an rwsem
mm: migrate: Account a transhuge page properly when rate limiting
mm: numa: Account for failed allocations and isolations as migration failures
mm: numa: Add THP migration for the NUMA working set scanning fault case build fix
mm: numa: Add THP migration for the NUMA working set scanning fault case.
mm: sched: numa: Delay PTE scanning until a task is scheduled on a new node
mm: sched: numa: Control enabling and disabling of NUMA balancing if !SCHED_DEBUG
mm: sched: numa: Control enabling and disabling of NUMA balancing
mm: sched: Adapt the scanning rate if a NUMA hinting fault does not migrate
mm: numa: Use a two-stage filter to restrict pages being migrated for unlikely task<->node relationships
mm: numa: migrate: Set last_nid on newly allocated page
mm: numa: split_huge_page: Transfer last_nid on tail page
mm: numa: Introduce last_nid to the page frame
sched: numa: Slowly increase the scanning period as NUMA faults are handled
mm: numa: Rate limit setting of pte_numa if node is saturated
mm: numa: Rate limit the amount of memory that is migrated between nodes
mm: numa: Structures for Migrate On Fault per NUMA migration rate limiting
mm: numa: Migrate pages handled during a pmd_numa hinting fault
mm: numa: Migrate on reference policy
...
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Thierry Reding
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c8bf2d8ba4 |
mm: compaction: Fix compiler warning
compact_capture_page() is only used if compaction is enabled so it should be moved into the corresponding #ifdef. Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.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> |
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Rafael Aquini
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5733c7d11d |
mm: introduce putback_movable_pages()
The PATCH "mm: introduce compaction and migration for virtio ballooned pages" hacks around putback_lru_pages() in order to allow ballooned pages to be re-inserted on balloon page list as if a ballooned page was like a LRU page. As ballooned pages are not legitimate LRU pages, this patch introduces putback_movable_pages() to properly cope with cases where the isolated pageset contains ballooned pages and LRU pages, thus fixing the mentioned inelegant hack around putback_lru_pages(). Signed-off-by: Rafael Aquini <aquini@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Andi Kleen <andi@firstfloor.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.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> |
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Rafael Aquini
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bf6bddf192 |
mm: introduce compaction and migration for ballooned pages
Memory fragmentation introduced by ballooning might reduce significantly the number of 2MB contiguous memory blocks that can be used within a guest, thus imposing performance penalties associated with the reduced number of transparent huge pages that could be used by the guest workload. This patch introduces the helper functions as well as the necessary changes to teach compaction and migration bits how to cope with pages which are part of a guest memory balloon, in order to make them movable by memory compaction procedures. Signed-off-by: Rafael Aquini <aquini@redhat.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.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> |
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Mel Gorman
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397487db69 |
mm: compaction: Add scanned and isolated counters for compaction
Compaction already has tracepoints to count scanned and isolated pages but it requires that ftrace be enabled and if that information has to be written to disk then it can be disruptive. This patch adds vmstat counters for compaction called compact_migrate_scanned, compact_free_scanned and compact_isolated. With these counters, it is possible to define a basic cost model for compaction. This approximates of how much work compaction is doing and can be compared that with an oprofile showing TLB misses and see if the cost of compaction is being offset by THP for example. Minimally a compaction patch can be evaluated in terms of whether it increases or decreases cost. The basic cost model looks like this Fundamental unit u: a word sizeof(void *) Ca = cost of struct page access = sizeof(struct page) / u Cmc = Cost migrate page copy = (Ca + PAGE_SIZE/u) * 2 Cmf = Cost migrate failure = Ca * 2 Ci = Cost page isolation = (Ca + Wi) where Wi is a constant that should reflect the approximate cost of the locking operation. Csm = Cost migrate scanning = Ca Csf = Cost free scanning = Ca Overall cost = (Csm * compact_migrate_scanned) + (Csf * compact_free_scanned) + (Ci * compact_isolated) + (Cmc * pgmigrate_success) + (Cmf * pgmigrate_failed) Where the values are read from /proc/vmstat. This is very basic and ignores certain costs such as the allocation cost to do a migrate page copy but any improvement to the model would still use the same vmstat counters. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> |
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Mel Gorman
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7b2a2d4a18 |
mm: migrate: Add a tracepoint for migrate_pages
The pgmigrate_success and pgmigrate_fail vmstat counters tells the user about migration activity but not the type or the reason. This patch adds a tracepoint to identify the type of page migration and why the page is being migrated. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> |
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Mel Gorman
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5647bc293a |
mm: compaction: Move migration fail/success stats to migrate.c
The compact_pages_moved and compact_pagemigrate_failed events are convenient for determining if compaction is active and to what degree migration is succeeding but it's at the wrong level. Other users of migration may also want to know if migration is working properly and this will be particularly true for any automated NUMA migration. This patch moves the counters down to migration with the new events called pgmigrate_success and pgmigrate_fail. The compact_blocks_moved counter is removed because while it was useful for debugging initially, it's worthless now as no meaningful conclusions can be drawn from its value. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> |
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Mel Gorman
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60177d31d2 |
mm: compaction: validate pfn range passed to isolate_freepages_block
Commit |
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Mel Gorman
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0db63d7e25 |
mm: compaction: correct the nr_strict va isolated check for CMA
Thierry reported that the "iron out" patch for isolate_freepages_block() had problems due to the strict check being too strict with "mm: compaction: Iron out isolate_freepages_block() and isolate_freepages_range() -fix1". It's possible that more pages than necessary are isolated but the check still fails and I missed that this fix was not picked up before RC1. This same problem has been identified in 3.7-RC1 by Tony Prisk and should be addressed by the following patch. Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Tony Prisk <linux@prisktech.co.nz> Reported-by: Thierry Reding <thierry.reding@avionic-design.de> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Richard Davies <richard@arachsys.com> Cc: Shaohua Li <shli@kernel.org> Cc: Avi Kivity <avi@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Minchan Kim
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e46a28790e |
CMA: migrate mlocked pages
Presently CMA cannot migrate mlocked pages so it ends up failing to allocate contiguous memory space. This patch makes mlocked pages be migrated out. Of course, it can affect realtime processes but in CMA usecase, contiguous memory allocation failing is far worse than access latency to an mlocked page being variable while CMA is running. If someone wants to make the system realtime, he shouldn't enable CMA because stalls can still happen at random times. [akpm@linux-foundation.org: tweak comment text, per Mel] Signed-off-by: Minchan Kim <minchan@kernel.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.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> |
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Mel Gorman
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62997027ca |
mm: compaction: clear PG_migrate_skip based on compaction and reclaim activity
Compaction caches if a pageblock was scanned and no pages were isolated so that the pageblocks can be skipped in the future to reduce scanning. This information is not cleared by the page allocator based on activity due to the impact it would have to the page allocator fast paths. Hence there is a requirement that something clear the cache or pageblocks will be skipped forever. Currently the cache is cleared if there were a number of recent allocation failures and it has not been cleared within the last 5 seconds. Time-based decisions like this are terrible as they have no relationship to VM activity and is basically a big hammer. Unfortunately, accurate heuristics would add cost to some hot paths so this patch implements a rough heuristic. There are two cases where the cache is cleared. 1. If a !kswapd process completes a compaction cycle (migrate and free scanner meet), the zone is marked compact_blockskip_flush. When kswapd goes to sleep, it will clear the cache. This is expected to be the common case where the cache is cleared. It does not really matter if kswapd happens to be asleep or going to sleep when the flag is set as it will be woken on the next allocation request. 2. If there have been multiple failures recently and compaction just finished being deferred then a process will clear the cache and start a full scan. This situation happens if there are multiple high-order allocation requests under heavy memory pressure. The clearing of the PG_migrate_skip bits and other scans is inherently racy but the race is harmless. For allocations that can fail such as THP, they will simply fail. For requests that cannot fail, they will retry the allocation. Tests indicated that scanning rates were roughly similar to when the time-based heuristic was used and the allocation success rates were similar. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Richard Davies <richard@arachsys.com> Cc: Shaohua Li <shli@kernel.org> Cc: Avi Kivity <avi@redhat.com> Cc: Rafael Aquini <aquini@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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c89511ab2f |
mm: compaction: Restart compaction from near where it left off
This is almost entirely based on Rik's previous patches and discussions with him about how this might be implemented. Order > 0 compaction stops when enough free pages of the correct page order have been coalesced. When doing subsequent higher order allocations, it is possible for compaction to be invoked many times. However, the compaction code always starts out looking for things to compact at the start of the zone, and for free pages to compact things to at the end of the zone. This can cause quadratic behaviour, with isolate_freepages starting at the end of the zone each time, even though previous invocations of the compaction code already filled up all free memory on that end of the zone. This can cause isolate_freepages to take enormous amounts of CPU with certain workloads on larger memory systems. This patch caches where the migration and free scanner should start from on subsequent compaction invocations using the pageblock-skip information. When compaction starts it begins from the cached restart points and will update the cached restart points until a page is isolated or a pageblock is skipped that would have been scanned by synchronous compaction. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Cc: Richard Davies <richard@arachsys.com> Cc: Shaohua Li <shli@kernel.org> Cc: Avi Kivity <avi@redhat.com> Acked-by: Rafael Aquini <aquini@redhat.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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bb13ffeb9f |
mm: compaction: cache if a pageblock was scanned and no pages were isolated
When compaction was implemented it was known that scanning could potentially be excessive. The ideal was that a counter be maintained for each pageblock but maintaining this information would incur a severe penalty due to a shared writable cache line. It has reached the point where the scanning costs are a serious problem, particularly on long-lived systems where a large process starts and allocates a large number of THPs at the same time. Instead of using a shared counter, this patch adds another bit to the pageblock flags called PG_migrate_skip. If a pageblock is scanned by either migrate or free scanner and 0 pages were isolated, the pageblock is marked to be skipped in the future. When scanning, this bit is checked before any scanning takes place and the block skipped if set. The main difficulty with a patch like this is "when to ignore the cached information?" If it's ignored too often, the scanning rates will still be excessive. If the information is too stale then allocations will fail that might have otherwise succeeded. In this patch o CMA always ignores the information o If the migrate and free scanner meet then the cached information will be discarded if it's at least 5 seconds since the last time the cache was discarded o If there are a large number of allocation failures, discard the cache. The time-based heuristic is very clumsy but there are few choices for a better event. Depending solely on multiple allocation failures still allows excessive scanning when THP allocations are failing in quick succession due to memory pressure. Waiting until memory pressure is relieved would cause compaction to continually fail instead of using reclaim/compaction to try allocate the page. The time-based mechanism is clumsy but a better option is not obvious. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Cc: Richard Davies <richard@arachsys.com> Cc: Shaohua Li <shli@kernel.org> Cc: Avi Kivity <avi@redhat.com> Acked-by: Rafael Aquini <aquini@redhat.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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753341a4b8 |
revert "mm: have order > 0 compaction start off where it left"
This reverts commit |
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Mel Gorman
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f40d1e42bb |
mm: compaction: acquire the zone->lock as late as possible
Compaction's free scanner acquires the zone->lock when checking for PageBuddy pages and isolating them. It does this even if there are no PageBuddy pages in the range. This patch defers acquiring the zone lock for as long as possible. In the event there are no free pages in the pageblock then the lock will not be acquired at all which reduces contention on zone->lock. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Cc: Richard Davies <richard@arachsys.com> Cc: Shaohua Li <shli@kernel.org> Cc: Avi Kivity <avi@redhat.com> Acked-by: Rafael Aquini <aquini@redhat.com> Acked-by: Minchan Kim <minchan@kernel.org> Tested-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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2a1402aa04 |
mm: compaction: acquire the zone->lru_lock as late as possible
Richard Davies and Shaohua Li have both reported lock contention problems in compaction on the zone and LRU locks as well as significant amounts of time being spent in compaction. This series aims to reduce lock contention and scanning rates to reduce that CPU usage. Richard reported at https://lkml.org/lkml/2012/9/21/91 that this series made a big different to a problem he reported in August: http://marc.info/?l=kvm&m=134511507015614&w=2 Patch 1 defers acquiring the zone->lru_lock as long as possible. Patch 2 defers acquiring the zone->lock as lock as possible. Patch 3 reverts Rik's "skip-free" patches as the core concept gets reimplemented later and the remaining patches are easier to understand if this is reverted first. Patch 4 adds a pageblock-skip bit to the pageblock flags to cache what pageblocks should be skipped by the migrate and free scanners. This drastically reduces the amount of scanning compaction has to do. Patch 5 reimplements something similar to Rik's idea except it uses the pageblock-skip information to decide where the scanners should restart from and does not need to wrap around. I tested this on 3.6-rc6 + linux-next/akpm. Kernels tested were akpm-20120920 3.6-rc6 + linux-next/akpm as of Septeber 20th, 2012 lesslock Patches 1-6 revert Patches 1-7 cachefail Patches 1-8 skipuseless Patches 1-9 Stress high-order allocation tests looked ok. Success rates are more or less the same with the full series applied but there is an expectation that there is less opportunity to race with other allocation requests if there is less scanning. The time to complete the tests did not vary that much and are uninteresting as were the vmstat statistics so I will not present them here. Using ftrace I recorded how much scanning was done by compaction and got this 3.6.0-rc6 3.6.0-rc6 3.6.0-rc6 3.6.0-rc6 3.6.0-rc6 akpm-20120920 lockless revert-v2r2 cachefail skipuseless Total free scanned 360753976 515414028 565479007 17103281 18916589 Total free isolated |
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Mel Gorman
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661c4cb9b8 |
mm: compaction: Update try_to_compact_pages()kerneldoc comment
Parameters were added without documentation, tut tut. Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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3cc668f4e3 |
mm: compaction: move fatal signal check out of compact_checklock_irqsave
Commit
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Shaohua Li
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e64c5237cf |
mm: compaction: abort compaction loop if lock is contended or run too long
isolate_migratepages_range() might isolate no pages if for example when zone->lru_lock is contended and running asynchronous compaction. In this case, we should abort compaction, otherwise, compact_zone will run a useless loop and make zone->lru_lock is even contended. An additional check is added to ensure that cc.migratepages and cc.freepages get properly drained whan compaction is aborted. [minchan@kernel.org: Putback pages isolated for migration if aborting] [akpm@linux-foundation.org: compact_zone_order requires non-NULL arg contended] [akpm@linux-foundation.org: make compact_zone_order() require non-NULL arg `contended'] [minchan@kernel.org: Putback pages isolated for migration if aborting] Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Bartlomiej Zolnierkiewicz
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d95ea5d18e |
cma: fix watermark checking
* Add ALLOC_CMA alloc flag and pass it to [__]zone_watermark_ok() (from Minchan Kim). * During watermark check decrease available free pages number by free CMA pages number if necessary (unmovable allocations cannot use pages from CMA areas). Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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1fb3f8ca0e |
mm: compaction: capture a suitable high-order page immediately when it is made available
While compaction is migrating pages to free up large contiguous blocks for allocation it races with other allocation requests that may steal these blocks or break them up. This patch alters direct compaction to capture a suitable free page as soon as it becomes available to reduce this race. It uses similar logic to split_free_page() to ensure that watermarks are still obeyed. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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4ffb6335da |
mm: compaction: update comment in try_to_compact_pages
Allocation success rates have been far lower since 3.4 due to commit |
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Mel Gorman
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c67fe3752a |
mm: compaction: Abort async compaction if locks are contended or taking too long
Jim Schutt reported a problem that pointed at compaction contending
heavily on locks. The workload is straight-forward and in his own words;
The systems in question have 24 SAS drives spread across 3 HBAs,
running 24 Ceph OSD instances, one per drive. FWIW these servers
are dual-socket Intel 5675 Xeons w/48 GB memory. I've got ~160
Ceph Linux clients doing dd simultaneously to a Ceph file system
backed by 12 of these servers.
Early in the test everything looks fine
procs -------------------memory------------------ ---swap-- -----io---- --system-- -----cpu-------
r b swpd free buff cache si so bi bo in cs us sy id wa st
31 15 0 287216 576 38606628 0 0 2 1158 2 14 1 3 95 0 0
27 15 0 225288 576 38583384 0 0 18 2222016 203357 134876 11 56 17 15 0
28 17 0 219256 576 38544736 0 0 11 2305932 203141 146296 11 49 23 17 0
6 18 0 215596 576 38552872 0 0 7 2363207 215264 166502 12 45 22 20 0
22 18 0 226984 576 38596404 0 0 3 2445741 223114 179527 12 43 23 22 0
and then it goes to pot
procs -------------------memory------------------ ---swap-- -----io---- --system-- -----cpu-------
r b swpd free buff cache si so bi bo in cs us sy id wa st
163 8 0 464308 576 36791368 0 0 11 22210 866 536 3 13 79 4 0
207 14 0 917752 576 36181928 0 0 712 1345376 134598 47367 7 90 1 2 0
123 12 0 685516 576 36296148 0 0 429 1386615 158494 60077 8 84 5 3 0
123 12 0 598572 576 36333728 0 0 1107 1233281 147542 62351 7 84 5 4 0
622 7 0 660768 576 36118264 0 0 557 1345548 151394 59353 7 85 4 3 0
223 11 0 283960 576 36463868 0 0 46 1107160 121846 33006 6 93 1 1 0
Note that system CPU usage is very high blocks being written out has
dropped by 42%. He analysed this with perf and found
perf record -g -a sleep 10
perf report --sort symbol --call-graph fractal,5
34.63% [k] _raw_spin_lock_irqsave
|
|--97.30%-- isolate_freepages
| compaction_alloc
| unmap_and_move
| migrate_pages
| compact_zone
| compact_zone_order
| try_to_compact_pages
| __alloc_pages_direct_compact
| __alloc_pages_slowpath
| __alloc_pages_nodemask
| alloc_pages_vma
| do_huge_pmd_anonymous_page
| handle_mm_fault
| do_page_fault
| page_fault
| |
| |--87.39%-- skb_copy_datagram_iovec
| | tcp_recvmsg
| | inet_recvmsg
| | sock_recvmsg
| | sys_recvfrom
| | system_call
| | __recv
| | |
| | --100.00%-- (nil)
| |
| --12.61%-- memcpy
--2.70%-- [...]
There was other data but primarily it is all showing that compaction is
contended heavily on the zone->lock and zone->lru_lock.
commit [
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Mel Gorman
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de74f1cc3b |
mm: have order > 0 compaction start near a pageblock with free pages
Commit
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Minchan Kim
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c81758fbe0 |
mm/compaction.c: fix deferring compaction mistake
Commit
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Rik van Riel
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7db8889ab0 |
mm: have order > 0 compaction start off where it left
Order > 0 compaction stops when enough free pages of the correct page order have been coalesced. When doing subsequent higher order allocations, it is possible for compaction to be invoked many times. However, the compaction code always starts out looking for things to compact at the start of the zone, and for free pages to compact things to at the end of the zone. This can cause quadratic behaviour, with isolate_freepages starting at the end of the zone each time, even though previous invocations of the compaction code already filled up all free memory on that end of the zone. This can cause isolate_freepages to take enormous amounts of CPU with certain workloads on larger memory systems. The obvious solution is to have isolate_freepages remember where it left off last time, and continue at that point the next time it gets invoked for an order > 0 compaction. This could cause compaction to fail if cc->free_pfn and cc->migrate_pfn are close together initially, in that case we restart from the end of the zone and try once more. Forced full (order == -1) compactions are left alone. [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: s/laste/last/, use 80 cols] Signed-off-by: Rik van Riel <riel@redhat.com> Reported-by: Jim Schutt <jaschut@sandia.gov> Tested-by: Jim Schutt <jaschut@sandia.gov> Cc: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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David Rientjes
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4bf2bba375 |
mm, thp: abort compaction if migration page cannot be charged to memcg
If page migration cannot charge the temporary page to the memcg, migrate_pages() will return -ENOMEM. This isn't considered in memory compaction however, and the loop continues to iterate over all pageblocks trying to isolate and migrate pages. If a small number of very large memcgs happen to be oom, however, these attempts will mostly be futile leading to an enormous amout of cpu consumption due to the page migration failures. This patch will short circuit and fail memory compaction if migrate_pages() returns -ENOMEM. COMPACT_PARTIAL is returned in case some migrations were successful so that the page allocator will retry. Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan@kernel.org> Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.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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Linus Torvalds
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68e3e92620 |
Revert "mm: compaction: handle incorrect MIGRATE_UNMOVABLE type pageblocks"
This reverts commit
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Hugh Dickins
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fa9add641b |
mm/memcg: apply add/del_page to lruvec
Take lruvec further: pass it instead of zone to add_page_to_lru_list() and del_page_from_lru_list(); and pagevec_lru_move_fn() pass lruvec down to its target functions. This cleanup eliminates a swathe of cruft in memcontrol.c, including mem_cgroup_lru_add_list(), mem_cgroup_lru_del_list() and mem_cgroup_lru_move_lists() - which never actually touched the lists. In their place, mem_cgroup_page_lruvec() to decide the lruvec, previously a side-effect of add, and mem_cgroup_update_lru_size() to maintain the lru_size stats. Whilst these are simplifications in their own right, the goal is to bring the evaluation of lruvec next to the spin_locking of the lrus, in preparation for a future patch. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Konstantin Khlebnikov
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f3fd4a6192 |
mm: remove lru type checks from __isolate_lru_page()
After patch "mm: forbid lumpy-reclaim in shrink_active_list()" we can completely remove anon/file and active/inactive lru type filters from __isolate_lru_page(), because isolation for 0-order reclaim always isolates pages from right lru list. And pages-isolation for lumpy shrink_inactive_list() or memory-compaction anyway allowed to isolate pages from all evictable lru lists. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@parallels.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Bartlomiej Zolnierkiewicz
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5ceb9ce6fe |
mm: compaction: handle incorrect MIGRATE_UNMOVABLE type pageblocks
When MIGRATE_UNMOVABLE pages are freed from MIGRATE_UNMOVABLE type pageblock (and some MIGRATE_MOVABLE pages are left in it) waiting until an allocation takes ownership of the block may take too long. The type of the pageblock remains unchanged so the pageblock cannot be used as a migration target during compaction. Fix it by: * Adding enum compact_mode (COMPACT_ASYNC_[MOVABLE,UNMOVABLE], and COMPACT_SYNC) and then converting sync field in struct compact_control to use it. * Adding nr_pageblocks_skipped field to struct compact_control and tracking how many destination pageblocks were of MIGRATE_UNMOVABLE type. If COMPACT_ASYNC_MOVABLE mode compaction ran fully in try_to_compact_pages() (COMPACT_COMPLETE) it implies that there is not a suitable page for allocation. In this case then check how if there were enough MIGRATE_UNMOVABLE pageblocks to try a second pass in COMPACT_ASYNC_UNMOVABLE mode. * Scanning the MIGRATE_UNMOVABLE pageblocks (during COMPACT_SYNC and COMPACT_ASYNC_UNMOVABLE compaction modes) and building a count based on finding PageBuddy pages, page_count(page) == 0 or PageLRU pages. If all pages within the MIGRATE_UNMOVABLE pageblock are in one of those three sets change the whole pageblock type to MIGRATE_MOVABLE. My particular test case (on a ARM EXYNOS4 device with 512 MiB, which means 131072 standard 4KiB pages in 'Normal' zone) is to: - allocate 120000 pages for kernel's usage - free every second page (60000 pages) of memory just allocated - allocate and use 60000 pages from user space - free remaining 60000 pages of kernel memory (now we have fragmented memory occupied mostly by user space pages) - try to allocate 100 order-9 (2048 KiB) pages for kernel's usage The results: - with compaction disabled I get 11 successful allocations - with compaction enabled - 14 successful allocations - with this patch I'm able to get all 100 successful allocations NOTE: If we can make kswapd aware of order-0 request during compaction, we can enhance kswapd with changing mode to COMPACT_ASYNC_FULL (COMPACT_ASYNC_MOVABLE + COMPACT_ASYNC_UNMOVABLE). Please see the following thread: http://marc.info/?l=linux-mm&m=133552069417068&w=2 [minchan@kernel.org: minor cleanups] Cc: Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Nazarewicz
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47118af076 |
mm: mmzone: MIGRATE_CMA migration type added
The MIGRATE_CMA migration type has two main characteristics: (i) only movable pages can be allocated from MIGRATE_CMA pageblocks and (ii) page allocator will never change migration type of MIGRATE_CMA pageblocks. This guarantees (to some degree) that page in a MIGRATE_CMA page block can always be migrated somewhere else (unless there's no memory left in the system). It is designed to be used for allocating big chunks (eg. 10MiB) of physically contiguous memory. Once driver requests contiguous memory, pages from MIGRATE_CMA pageblocks may be migrated away to create a contiguous block. To minimise number of migrations, MIGRATE_CMA migration type is the last type tried when page allocator falls back to other migration types when requested. Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Tested-by: Rob Clark <rob.clark@linaro.org> Tested-by: Ohad Ben-Cohen <ohad@wizery.com> Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> Tested-by: Robert Nelson <robertcnelson@gmail.com> Tested-by: Barry Song <Baohua.Song@csr.com> |
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Michal Nazarewicz
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ff9543fd32 |
mm: compaction: export some of the functions
This commit exports some of the functions from compaction.c file outside of it adding their declaration into internal.h header file so that other mm related code can use them. This forced compaction.c to always be compiled (as opposed to being compiled only if CONFIG_COMPACTION is defined) but as to avoid introducing code that user did not ask for, part of the compaction.c is now wrapped in on #ifdef. Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Tested-by: Rob Clark <rob.clark@linaro.org> Tested-by: Ohad Ben-Cohen <ohad@wizery.com> Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> Tested-by: Robert Nelson <robertcnelson@gmail.com> Tested-by: Barry Song <Baohua.Song@csr.com> |
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Michal Nazarewicz
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85aa125f00 |
mm: compaction: introduce isolate_freepages_range()
This commit introduces isolate_freepages_range() function which generalises isolate_freepages_block() so that it can be used on arbitrary PFN ranges. isolate_freepages_block() is left with only minor changes. Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Tested-by: Rob Clark <rob.clark@linaro.org> Tested-by: Ohad Ben-Cohen <ohad@wizery.com> Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> Tested-by: Robert Nelson <robertcnelson@gmail.com> Tested-by: Barry Song <Baohua.Song@csr.com> |
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Michal Nazarewicz
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03d44192f6 |
mm: compaction: introduce map_pages()
This commit creates a map_pages() function which map pages freed using split_free_pages(). This merely moves some code from isolate_freepages() so that it can be reused in other places. Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Tested-by: Robert Nelson <robertcnelson@gmail.com> Tested-by: Barry Song <Baohua.Song@csr.com> |
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Michal Nazarewicz
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2fe86e0004 |
mm: compaction: introduce isolate_migratepages_range()
This commit introduces isolate_migratepages_range() function which extracts functionality from isolate_migratepages() so that it can be used on arbitrary PFN ranges. isolate_migratepages() function is implemented as a simple wrapper around isolate_migratepages_range(). Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Tested-by: Rob Clark <rob.clark@linaro.org> Tested-by: Ohad Ben-Cohen <ohad@wizery.com> Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> Tested-by: Robert Nelson <robertcnelson@gmail.com> Tested-by: Barry Song <Baohua.Song@csr.com> |
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Dan Carpenter
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aad6ec3777 |
mm: compaction: make compact_control order signed
"order" is -1 when compacting via /proc/sys/vm/compact_memory. Making it unsigned causes a bug in __compact_pgdat() when we test: if (cc->order < 0 || !compaction_deferred(zone, cc->order)) compact_zone(zone, cc); [akpm@linux-foundation.org: make __compact_pgdat()'s comparison match other code sites] Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Minchan Kim <minchan@kernel.org> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
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8575ec29f6 |
compact_pgdat: workaround lockdep warning in kswapd
I get this lockdep warning from swapping load on linux-next, due to "vmscan: kswapd carefully call compaction". ================================= [ INFO: inconsistent lock state ] 3.3.0-rc2-next-20120201 #5 Not tainted --------------------------------- inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage. kswapd0/28 [HC0[0]:SC0[0]:HE1:SE1] takes: (pcpu_alloc_mutex){+.+.?.}, at: [<ffffffff810d6684>] pcpu_alloc+0x67/0x325 {RECLAIM_FS-ON-W} state was registered at: [<ffffffff81099b75>] mark_held_locks+0xd7/0x103 [<ffffffff8109a13c>] lockdep_trace_alloc+0x85/0x9e [<ffffffff810f6bdc>] __kmalloc+0x6c/0x14b [<ffffffff810d57fd>] pcpu_mem_zalloc+0x59/0x62 [<ffffffff810d5d16>] pcpu_extend_area_map+0x26/0xb1 [<ffffffff810d679f>] pcpu_alloc+0x182/0x325 [<ffffffff810d694d>] __alloc_percpu+0xb/0xd [<ffffffff8142ebfd>] snmp_mib_init+0x1e/0x2e [<ffffffff8185cd8d>] ipv4_mib_init_net+0x7a/0x184 [<ffffffff813dc963>] ops_init.clone.0+0x6b/0x73 [<ffffffff813dc9cc>] register_pernet_operations+0x61/0xa0 [<ffffffff813dca8e>] register_pernet_subsys+0x29/0x42 [<ffffffff8185d044>] inet_init+0x1ad/0x252 [<ffffffff810002e3>] do_one_initcall+0x7a/0x12f [<ffffffff81832bc5>] kernel_init+0x9d/0x11e [<ffffffff814e51e4>] kernel_thread_helper+0x4/0x10 irq event stamp: 656613 hardirqs last enabled at (656613): [<ffffffff814e0ddc>] __mutex_unlock_slowpath+0x104/0x128 hardirqs last disabled at (656612): [<ffffffff814e0d34>] __mutex_unlock_slowpath+0x5c/0x128 softirqs last enabled at (655568): [<ffffffff8105b4a5>] __do_softirq+0x120/0x136 softirqs last disabled at (654757): [<ffffffff814e52dc>] call_softirq+0x1c/0x30 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(pcpu_alloc_mutex); <Interrupt> lock(pcpu_alloc_mutex); *** DEADLOCK *** no locks held by kswapd0/28. stack backtrace: Pid: 28, comm: kswapd0 Not tainted 3.3.0-rc2-next-20120201 #5 Call Trace: [<ffffffff810981f4>] print_usage_bug+0x1bf/0x1d0 [<ffffffff81096c3e>] ? print_irq_inversion_bug+0x1d9/0x1d9 [<ffffffff810982c0>] mark_lock_irq+0xbb/0x22e [<ffffffff810c5399>] ? free_hot_cold_page+0x13d/0x14f [<ffffffff81098684>] mark_lock+0x251/0x331 [<ffffffff81098893>] mark_irqflags+0x12f/0x141 [<ffffffff81098e32>] __lock_acquire+0x58d/0x753 [<ffffffff810d6684>] ? pcpu_alloc+0x67/0x325 [<ffffffff81099433>] lock_acquire+0x54/0x6a [<ffffffff810d6684>] ? pcpu_alloc+0x67/0x325 [<ffffffff8107a5b8>] ? add_preempt_count+0xa9/0xae [<ffffffff814e0a21>] mutex_lock_nested+0x5e/0x315 [<ffffffff810d6684>] ? pcpu_alloc+0x67/0x325 [<ffffffff81098f81>] ? __lock_acquire+0x6dc/0x753 [<ffffffff810c9fb0>] ? __pagevec_release+0x2c/0x2c [<ffffffff810d6684>] pcpu_alloc+0x67/0x325 [<ffffffff810c9fb0>] ? __pagevec_release+0x2c/0x2c [<ffffffff810d694d>] __alloc_percpu+0xb/0xd [<ffffffff8106c35e>] schedule_on_each_cpu+0x23/0x110 [<ffffffff810c9fcb>] lru_add_drain_all+0x10/0x12 [<ffffffff810f126f>] __compact_pgdat+0x20/0x182 [<ffffffff810f15c2>] compact_pgdat+0x27/0x29 [<ffffffff810c306b>] ? zone_watermark_ok+0x1a/0x1c [<ffffffff810cdf6f>] balance_pgdat+0x732/0x751 [<ffffffff810ce0ed>] kswapd+0x15f/0x178 [<ffffffff810cdf8e>] ? balance_pgdat+0x751/0x751 [<ffffffff8106fd11>] kthread+0x84/0x8c [<ffffffff814e51e4>] kernel_thread_helper+0x4/0x10 [<ffffffff810787ed>] ? finish_task_switch+0x85/0xea [<ffffffff814e3861>] ? retint_restore_args+0xe/0xe [<ffffffff8106fc8d>] ? __init_kthread_worker+0x56/0x56 [<ffffffff814e51e0>] ? gs_change+0xb/0xb The RECLAIM_FS notations indicate that it's doing the GFP_FS checking that Nick hacked into lockdep a while back: I think we're intended to read that "<Interrupt>" in the DEADLOCK scenario as "<Direct reclaim>". I'm hazy, I have not reached any conclusion as to whether it's right to complain or not; but I believe it's uneasy about kswapd now doing the mutex_lock(&pcpu_alloc_mutex) which lru_add_drain_all() entails. Nor have I reached any conclusion as to whether it's important for kswapd to do that draining or not. But so as not to get blocked on this, with lockdep disabled from giving further reports, here's a patch which removes the lru_add_drain_all() from kswapd's callpath (and calls it only once from compact_nodes(), instead of once per node). Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Rik van Riel
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aff622495c |
vmscan: only defer compaction for failed order and higher
Currently a failed order-9 (transparent hugepage) compaction can lead to memory compaction being temporarily disabled for a memory zone. Even if we only need compaction for an order 2 allocation, eg. for jumbo frames networking. The fix is relatively straightforward: keep track of the highest order at which compaction is succeeding, and only defer compaction for orders at which compaction is failing. Signed-off-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hillf Danton <dhillf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Rik van Riel
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7be62de99a |
vmscan: kswapd carefully call compaction
With CONFIG_COMPACTION enabled, kswapd does not try to free contiguous free pages, even when it is woken for a higher order request. This could be bad for eg. jumbo frame network allocations, which are done from interrupt context and cannot compact memory themselves. Higher than before allocation failure rates in the network receive path have been observed in kernels with compaction enabled. Teach kswapd to defragment the memory zones in a node, but only if required and compaction is not deferred in a zone. [akpm@linux-foundation.org: reduce scope of zones_need_compaction] Signed-off-by: Rik van Riel <riel@redhat.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hillf Danton <dhillf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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dc9086004b |
mm: compaction: check for overlapping nodes during isolation for migration
When isolating pages for migration, migration starts at the start of a zone while the free scanner starts at the end of the zone. Migration avoids entering a new zone by never going beyond the free scanned. Unfortunately, in very rare cases nodes can overlap. When this happens, migration isolates pages without the LRU lock held, corrupting lists which will trigger errors in reclaim or during page free such as in the following oops BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: [<ffffffff810f795c>] free_pcppages_bulk+0xcc/0x450 PGD 1dda554067 PUD 1e1cb58067 PMD 0 Oops: 0000 [#1] SMP CPU 37 Pid: 17088, comm: memcg_process_s Tainted: G X RIP: free_pcppages_bulk+0xcc/0x450 Process memcg_process_s (pid: 17088, threadinfo ffff881c2926e000, task ffff881c2926c0c0) Call Trace: free_hot_cold_page+0x17e/0x1f0 __pagevec_free+0x90/0xb0 release_pages+0x22a/0x260 pagevec_lru_move_fn+0xf3/0x110 putback_lru_page+0x66/0xe0 unmap_and_move+0x156/0x180 migrate_pages+0x9e/0x1b0 compact_zone+0x1f3/0x2f0 compact_zone_order+0xa2/0xe0 try_to_compact_pages+0xdf/0x110 __alloc_pages_direct_compact+0xee/0x1c0 __alloc_pages_slowpath+0x370/0x830 __alloc_pages_nodemask+0x1b1/0x1c0 alloc_pages_vma+0x9b/0x160 do_huge_pmd_anonymous_page+0x160/0x270 do_page_fault+0x207/0x4c0 page_fault+0x25/0x30 The "X" in the taint flag means that external modules were loaded but but is unrelated to the bug triggering. The real problem was because the PFN layout looks like this Zone PFN ranges: DMA 0x00000010 -> 0x00001000 DMA32 0x00001000 -> 0x00100000 Normal 0x00100000 -> 0x01e80000 Movable zone start PFN for each node early_node_map[14] active PFN ranges 0: 0x00000010 -> 0x0000009b 0: 0x00000100 -> 0x0007a1ec 0: 0x0007a354 -> 0x0007a379 0: 0x0007f7ff -> 0x0007f800 0: 0x00100000 -> 0x00680000 1: 0x00680000 -> 0x00e80000 0: 0x00e80000 -> 0x01080000 1: 0x01080000 -> 0x01280000 0: 0x01280000 -> 0x01480000 1: 0x01480000 -> 0x01680000 0: 0x01680000 -> 0x01880000 1: 0x01880000 -> 0x01a80000 0: 0x01a80000 -> 0x01c80000 1: 0x01c80000 -> 0x01e80000 The fix is straight-forward. isolate_migratepages() has to make a similar check to isolate_freepage to ensure that it never isolates pages from a zone it does not hold the LRU lock for. This was discovered in a 3.0-based kernel but it affects 3.1.x, 3.2.x and current mainline. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Michal Nazarewicz <mina86@mina86.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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Mel Gorman
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0bf380bc70 |
mm: compaction: check pfn_valid when entering a new MAX_ORDER_NR_PAGES block during isolation for migration
When isolating for migration, migration starts at the start of a zone which is not necessarily pageblock aligned. Further, it stops isolating when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally not aligned. This allows isolate_migratepages() to call pfn_to_page() on an invalid PFN which can result in a crash. This was originally reported against a 3.0-based kernel with the following trace in a crash dump. PID: 9902 TASK: d47aecd0 CPU: 0 COMMAND: "memcg_process_s" #0 [d72d3ad0] crash_kexec at c028cfdb #1 [d72d3b24] oops_end at c05c5322 #2 [d72d3b38] __bad_area_nosemaphore at c0227e60 #3 [d72d3bec] bad_area at c0227fb6 #4 [d72d3c00] do_page_fault at c05c72ec #5 [d72d3c80] error_code (via page_fault) at c05c47a4 EAX: 00000000 EBX: 000c0000 ECX: 00000001 EDX: 00000807 EBP: 000c0000 DS: 007b ESI: 00000001 ES: 007b EDI: f3000a80 GS: 6f50 CS: 0060 EIP: c030b15a ERR: ffffffff EFLAGS: 00010002 #6 [d72d3cb4] isolate_migratepages at c030b15a #7 [d72d3d14] zone_watermark_ok at c02d26cb #8 [d72d3d2c] compact_zone at |
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Mel Gorman
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a6bc32b899 |
mm: compaction: introduce sync-light migration for use by compaction
This patch adds a lightweight sync migrate operation MIGRATE_SYNC_LIGHT mode that avoids writing back pages to backing storage. Async compaction maps to MIGRATE_ASYNC while sync compaction maps to MIGRATE_SYNC_LIGHT. For other migrate_pages users such as memory hotplug, MIGRATE_SYNC is used. This avoids sync compaction stalling for an excessive length of time, particularly when copying files to a USB stick where there might be a large number of dirty pages backed by a filesystem that does not support ->writepages. [aarcange@redhat.com: This patch is heavily based on Andrea's work] [akpm@linux-foundation.org: fix fs/nfs/write.c build] [akpm@linux-foundation.org: fix fs/btrfs/disk-io.c build] Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Dave Jones <davej@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Andy Isaacson <adi@hexapodia.org> Cc: Nai Xia <nai.xia@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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c824493528 |
mm: compaction: make isolate_lru_page() filter-aware again
Commit
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Mel Gorman
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b16d3d5a52 |
mm: compaction: use synchronous compaction for /proc/sys/vm/compact_memory
When asynchronous compaction was introduced, the /proc/sys/vm/compact_memory handler should have been updated to always use synchronous compaction. This did not happen so this patch addresses it. The assumption is if a user writes to /proc/sys/vm/compact_memory, they are willing for that process to stall. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Dave Jones <davej@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Andy Isaacson <adi@hexapodia.org> Cc: Nai Xia <nai.xia@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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a77ebd333c |
mm: compaction: allow compaction to isolate dirty pages
Short summary: There are severe stalls when a USB stick using VFAT is used with THP enabled that are reduced by this series. If you are experiencing this problem, please test and report back and considering I have seen complaints from openSUSE and Fedora users on this as well as a few private mails, I'm guessing it's a widespread issue. This is a new type of USB-related stall because it is due to synchronous compaction writing where as in the past the big problem was dirty pages reaching the end of the LRU and being written by reclaim. Am cc'ing Andrew this time and this series would replace mm-do-not-stall-in-synchronous-compaction-for-thp-allocations.patch. I'm also cc'ing Dave Jones as he might have merged that patch to Fedora for wider testing and ideally it would be reverted and replaced by this series. That said, the later patches could really do with some review. If this series is not the answer then a new direction needs to be discussed because as it is, the stalls are unacceptable as the results in this leader show. For testers that try backporting this to 3.1, it won't work because there is a non-obvious dependency on not writing back pages in direct reclaim so you need those patches too. Changelog since V5 o Rebase to 3.2-rc5 o Tidy up the changelogs a bit Changelog since V4 o Added reviewed-bys, credited Andrea properly for sync-light o Allow dirty pages without mappings to be considered for migration o Bound the number of pages freed for compaction o Isolate PageReclaim pages on their own LRU list This is against 3.2-rc5 and follows on from discussions on "mm: Do not stall in synchronous compaction for THP allocations" and "[RFC PATCH 0/5] Reduce compaction-related stalls". Initially, the proposed patch eliminated stalls due to compaction which sometimes resulted in user-visible interactivity problems on browsers by simply never using sync compaction. The downside was that THP success allocation rates were lower because dirty pages were not being migrated as reported by Andrea. His approach at fixing this was nacked on the grounds that it reverted fixes from Rik merged that reduced the amount of pages reclaimed as it severely impacted his workloads performance. This series attempts to reconcile the requirements of maximising THP usage, without stalling in a user-visible fashion due to compaction or cheating by reclaiming an excessive number of pages. Patch 1 partially reverts commit |
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Hillf Danton
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31b8384a55 |
mm: compaction: push isolate search base of compact control one pfn ahead
After isolated the current pfn will no longer be scanned and isolated if the next round is necessary, so push the isolate_migratepages search base of the given compact_control one step ahead. Signed-off-by: Hillf Danton <dhillf@gmail.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |