From: kbuild test robot <lkp@intel.com>
To: Dave Chinner <david@fromorbit.com>
Cc: kbuild-all@01.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 04/24] shrinker: defer work only to kswapd
Date: Thu, 8 Aug 2019 02:00:48 +0800 [thread overview]
Message-ID: <201908080157.6xAysUVU%lkp@intel.com> (raw)
In-Reply-To: <20190801021752.4986-5-david@fromorbit.com>
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Hi Dave,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on linus/master]
[cannot apply to v5.3-rc3 next-20190807]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Dave-Chinner/mm-xfs-non-blocking-inode-reclaim/20190804-042311
config: i386-randconfig-a003-201931 (attached as .config)
compiler: gcc-4.9 (Debian 4.9.2-10+deb8u1) 4.9.2
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
mm/vmscan.c: In function 'do_shrink_slab':
>> mm/vmscan.c:539:34: warning: passing argument 1 of 'atomic64_xchg' from incompatible pointer type
deferred_count = atomic64_xchg(&shrinker->nr_deferred[nid], 0);
^
In file included from arch/x86/include/asm/atomic.h:265:0,
from include/linux/atomic.h:7,
from include/linux/jump_label.h:249,
from include/linux/static_key.h:1,
from arch/x86/include/asm/nospec-branch.h:6,
from arch/x86/include/asm/paravirt_types.h:46,
from arch/x86/include/asm/ptrace.h:94,
from arch/x86/include/asm/math_emu.h:5,
from arch/x86/include/asm/processor.h:12,
from arch/x86/include/asm/cpufeature.h:5,
from arch/x86/include/asm/thread_info.h:53,
from include/linux/thread_info.h:38,
from arch/x86/include/asm/preempt.h:7,
from include/linux/preempt.h:78,
from include/linux/spinlock.h:51,
from include/linux/mmzone.h:8,
from include/linux/gfp.h:6,
from include/linux/mm.h:10,
from mm/vmscan.c:17:
include/asm-generic/atomic-instrumented.h:1421:1: note: expected 'struct atomic64_t *' but argument is of type 'struct atomic_long_t *'
atomic64_xchg(atomic64_t *v, s64 i)
^
vim +/atomic64_xchg +539 mm/vmscan.c
498
499 static unsigned long do_shrink_slab(struct shrink_control *shrinkctl,
500 struct shrinker *shrinker, int priority)
501 {
502 unsigned long freed = 0;
503 int64_t freeable_objects = 0;
504 int64_t scan_count;
505 int64_t scanned_objects = 0;
506 int64_t next_deferred = 0;
507 int64_t deferred_count = 0;
508 long new_nr;
509 int nid = shrinkctl->nid;
510 long batch_size = shrinker->batch ? shrinker->batch
511 : SHRINK_BATCH;
512
513 if (!(shrinker->flags & SHRINKER_NUMA_AWARE))
514 nid = 0;
515
516 scan_count = shrink_scan_count(shrinkctl, shrinker, priority,
517 &freeable_objects);
518 if (scan_count == 0 || scan_count == SHRINK_EMPTY)
519 return scan_count;
520
521 /*
522 * If kswapd, we take all the deferred work and do it here. We don't let
523 * direct reclaim do this, because then it means some poor sod is going
524 * to have to do somebody else's GFP_NOFS reclaim, and it hides the real
525 * amount of reclaim work from concurrent kswapd operations. Hence we do
526 * the work in the wrong place, at the wrong time, and it's largely
527 * unpredictable.
528 *
529 * By doing the deferred work only in kswapd, we can schedule the work
530 * according the the reclaim priority - low priority reclaim will do
531 * less deferred work, hence we'll do more of the deferred work the more
532 * desperate we become for free memory. This avoids the need for needing
533 * to specifically avoid deferred work windup as low amount os memory
534 * pressure won't excessive trim caches anymore.
535 */
536 if (current_is_kswapd()) {
537 int64_t deferred_scan;
538
> 539 deferred_count = atomic64_xchg(&shrinker->nr_deferred[nid], 0);
540
541 /* we want to scan 5-10% of the deferred work here at minimum */
542 deferred_scan = deferred_count;
543 if (priority)
544 do_div(deferred_scan, priority);
545 scan_count += deferred_scan;
546
547 /*
548 * If there is more deferred work than the number of freeable
549 * items in the cache, limit the amount of work we will carry
550 * over to the next kswapd run on this cache. This prevents
551 * deferred work windup.
552 */
553 if (deferred_count > freeable_objects * 2)
554 deferred_count = freeable_objects * 2;
555
556 }
557
558 /*
559 * Avoid risking looping forever due to too large nr value:
560 * never try to free more than twice the estimate number of
561 * freeable entries.
562 */
563 if (scan_count > freeable_objects * 2)
564 scan_count = freeable_objects * 2;
565
566 trace_mm_shrink_slab_start(shrinker, shrinkctl, deferred_count,
567 freeable_objects, scan_count,
568 scan_count, priority);
569
570 /*
571 * If the shrinker can't run (e.g. due to gfp_mask constraints), then
572 * defer the work to a context that can scan the cache.
573 */
574 if (shrinkctl->will_defer)
575 goto done;
576
577 /*
578 * Normally, we should not scan less than batch_size objects in one
579 * pass to avoid too frequent shrinker calls, but if the slab has less
580 * than batch_size objects in total and we are really tight on memory,
581 * we will try to reclaim all available objects, otherwise we can end
582 * up failing allocations although there are plenty of reclaimable
583 * objects spread over several slabs with usage less than the
584 * batch_size.
585 *
586 * We detect the "tight on memory" situations by looking at the total
587 * number of objects we want to scan (total_scan). If it is greater
588 * than the total number of objects on slab (freeable), we must be
589 * scanning at high prio and therefore should try to reclaim as much as
590 * possible.
591 */
592 while (scan_count >= batch_size ||
593 scan_count >= freeable_objects) {
594 unsigned long ret;
595 unsigned long nr_to_scan = min_t(long, batch_size, scan_count);
596
597 shrinkctl->nr_to_scan = nr_to_scan;
598 shrinkctl->nr_scanned = nr_to_scan;
599 ret = shrinker->scan_objects(shrinker, shrinkctl);
600 if (ret == SHRINK_STOP)
601 break;
602 freed += ret;
603
604 count_vm_events(SLABS_SCANNED, shrinkctl->nr_scanned);
605 scan_count -= shrinkctl->nr_scanned;
606 scanned_objects += shrinkctl->nr_scanned;
607
608 cond_resched();
609 }
610
611 done:
612 if (deferred_count)
613 next_deferred = deferred_count - scanned_objects;
614 else if (scan_count > 0)
615 next_deferred = scan_count;
616 /*
617 * move the unused scan count back into the shrinker in a
618 * manner that handles concurrent updates. If we exhausted the
619 * scan, there is no need to do an update.
620 */
621 if (next_deferred > 0)
622 new_nr = atomic_long_add_return(next_deferred,
623 &shrinker->nr_deferred[nid]);
624 else
625 new_nr = atomic_long_read(&shrinker->nr_deferred[nid]);
626
627 trace_mm_shrink_slab_end(shrinker, nid, freed, deferred_count, new_nr,
628 scan_count);
629 return freed;
630 }
631
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
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next prev parent reply other threads:[~2019-08-07 18:01 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-01 2:17 [RFC] [PATCH 00/24] mm, xfs: non-blocking inode reclaim Dave Chinner
2019-08-01 2:17 ` [PATCH 01/24] mm: directed shrinker work deferral Dave Chinner
2019-08-02 15:27 ` Brian Foster
2019-08-04 1:49 ` Dave Chinner
2019-08-05 17:42 ` Brian Foster
2019-08-05 23:43 ` Dave Chinner
2019-08-06 12:27 ` Brian Foster
2019-08-06 22:22 ` Dave Chinner
2019-08-07 11:13 ` Brian Foster
2019-08-01 2:17 ` [PATCH 02/24] shrinkers: use will_defer for GFP_NOFS sensitive shrinkers Dave Chinner
2019-08-02 15:27 ` Brian Foster
2019-08-04 1:50 ` Dave Chinner
2019-08-01 2:17 ` [PATCH 03/24] mm: factor shrinker work calculations Dave Chinner
2019-08-02 15:08 ` Nikolay Borisov
2019-08-04 2:05 ` Dave Chinner
2019-08-02 15:31 ` Brian Foster
2019-08-01 2:17 ` [PATCH 04/24] shrinker: defer work only to kswapd Dave Chinner
2019-08-02 15:34 ` Brian Foster
2019-08-04 16:48 ` Nikolay Borisov
2019-08-04 21:37 ` Dave Chinner
2019-08-07 16:12 ` kbuild test robot
2019-08-07 18:00 ` kbuild test robot [this message]
2019-08-01 2:17 ` [PATCH 05/24] shrinker: clean up variable types and tracepoints Dave Chinner
2019-08-01 2:17 ` [PATCH 06/24] mm: reclaim_state records pages reclaimed, not slabs Dave Chinner
2019-08-01 2:17 ` [PATCH 07/24] mm: back off direct reclaim on excessive shrinker deferral Dave Chinner
2019-08-01 2:17 ` [PATCH 08/24] mm: kswapd backoff for shrinkers Dave Chinner
2019-08-01 2:17 ` [PATCH 09/24] xfs: don't allow log IO to be throttled Dave Chinner
2019-08-01 13:39 ` Chris Mason
2019-08-01 23:58 ` Dave Chinner
2019-08-02 8:12 ` Christoph Hellwig
2019-08-02 14:11 ` Chris Mason
2019-08-02 18:34 ` Matthew Wilcox
2019-08-02 23:28 ` Dave Chinner
2019-08-05 18:32 ` Chris Mason
2019-08-05 23:09 ` Dave Chinner
2019-08-01 2:17 ` [PATCH 10/24] xfs: fix missed wakeup on l_flush_wait Dave Chinner
2019-08-01 2:17 ` [PATCH 11/24] xfs:: account for memory freed from metadata buffers Dave Chinner
2019-08-01 8:16 ` Christoph Hellwig
2019-08-01 9:21 ` Dave Chinner
2019-08-06 5:51 ` Christoph Hellwig
2019-08-01 2:17 ` [PATCH 12/24] xfs: correctly acount for reclaimable slabs Dave Chinner
2019-08-06 5:52 ` Christoph Hellwig
2019-08-06 21:05 ` Dave Chinner
2019-08-01 2:17 ` [PATCH 13/24] xfs: synchronous AIL pushing Dave Chinner
2019-08-05 17:51 ` Brian Foster
2019-08-05 23:21 ` Dave Chinner
2019-08-06 12:29 ` Brian Foster
2019-08-01 2:17 ` [PATCH 14/24] xfs: tail updates only need to occur when LSN changes Dave Chinner
2019-08-05 17:53 ` Brian Foster
2019-08-05 23:28 ` Dave Chinner
2019-08-06 5:33 ` Dave Chinner
2019-08-06 12:53 ` Brian Foster
2019-08-06 21:11 ` Dave Chinner
2019-08-01 2:17 ` [PATCH 15/24] xfs: eagerly free shadow buffers to reduce CIL footprint Dave Chinner
2019-08-05 18:03 ` Brian Foster
2019-08-05 23:33 ` Dave Chinner
2019-08-06 12:57 ` Brian Foster
2019-08-06 21:21 ` Dave Chinner
2019-08-01 2:17 ` [PATCH 16/24] xfs: Lower CIL flush limit for large logs Dave Chinner
2019-08-04 17:12 ` Nikolay Borisov
2019-08-01 2:17 ` [PATCH 17/24] xfs: don't block kswapd in inode reclaim Dave Chinner
2019-08-06 18:21 ` Brian Foster
2019-08-06 21:27 ` Dave Chinner
2019-08-07 11:14 ` Brian Foster
2019-08-01 2:17 ` [PATCH 18/24] xfs: reduce kswapd blocking on inode locking Dave Chinner
2019-08-06 18:22 ` Brian Foster
2019-08-06 21:33 ` Dave Chinner
2019-08-07 11:30 ` Brian Foster
2019-08-07 23:16 ` Dave Chinner
2019-08-01 2:17 ` [PATCH 19/24] xfs: kill background reclaim work Dave Chinner
2019-08-01 2:17 ` [PATCH 20/24] xfs: use AIL pushing for inode reclaim IO Dave Chinner
2019-08-07 18:09 ` Brian Foster
2019-08-07 23:10 ` Dave Chinner
2019-08-08 16:20 ` Brian Foster
2019-08-01 2:17 ` [PATCH 21/24] xfs: remove mode from xfs_reclaim_inodes() Dave Chinner
2019-08-01 2:17 ` [PATCH 22/24] xfs: track reclaimable inodes using a LRU list Dave Chinner
2019-08-08 16:36 ` Brian Foster
2019-08-09 0:10 ` Dave Chinner
2019-08-01 2:17 ` [PATCH 23/24] xfs: reclaim inodes from the LRU Dave Chinner
2019-08-08 16:39 ` Brian Foster
2019-08-09 1:20 ` Dave Chinner
2019-08-09 12:36 ` Brian Foster
2019-08-11 2:17 ` Dave Chinner
2019-08-11 12:46 ` Brian Foster
2019-08-01 2:17 ` [PATCH 24/24] xfs: remove unusued old inode reclaim code Dave Chinner
2019-08-06 5:57 ` [RFC] [PATCH 00/24] mm, xfs: non-blocking inode reclaim Christoph Hellwig
2019-08-06 21:37 ` Dave Chinner
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