Messages in this thread Patch in this message | | | Date | Wed, 8 Jul 2009 11:19:01 +0800 | From | Wu Fengguang <> | Subject | Re: [RFC PATCH 1/2] vmscan don't isolate too many pages |
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On Wed, Jul 08, 2009 at 02:59:29AM +0800, Rik van Riel wrote: > KOSAKI Motohiro wrote: > > > FAQ > > ------- > > Q: Why do you compared zone accumulate pages, not individual zone pages? > > A: If we check individual zone, #-of-reclaimer is restricted by smallest zone. > > it mean decreasing the performance of the system having small dma zone. > > That is a clever solution! I was playing around a bit with > doing it on a per-zone basis. Your idea is much nicer. > > However, I can see one potential problem with your patch: > > + nr_inactive += zone_page_state(zone, NR_INACTIVE_ANON); > + nr_inactive += zone_page_state(zone, NR_INACTIVE_FILE); > + nr_isolated += zone_page_state(zone, NR_ISOLATED_ANON); > + nr_isolated += zone_page_state(zone, NR_ISOLATED_FILE); > + } > + > + return nr_isolated > nr_inactive; > > What if we ran out of swap space, or are not scanning the > anon list at all for some reason? > > It is possible that there are no inactive_file pages left, > with all file pages already isolated, and your function > still letting reclaimers through.
Good catch!
If swap is always off, NR_ISOLATED_ANON = 0. So it becomes
NR_ISOLATED_FILE > NR_INACTIVE_FILE + NR_INACTIVE_ANON
which will never be true if there are more anon pages than file pages.
If swap is on but goes full at some time, comparing *ANON is also meaningless because the anon list won't be scanned.
> This means you could still get a spurious OOM. > > I guess I should mail out my (ugly) approach, so we can > compare the two :)
And it helps to be aware of all the alternatives, now and future :)
KOSAKI, I tested this updated patch. The OOM seems to be gone, but now the process could sleep for too long time.
[ 316.756006] BUG: soft lockup - CPU#1 stuck for 61s! [msgctl11:12497] [ 316.756006] Modules linked in: drm snd_hda_codec_analog snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_seq snd_timer snd_seq_device iwlagn snd iwlcore soundcore snd_page_alloc video [ 316.756006] irq event stamp: 269858 [ 316.756006] hardirqs last enabled at (269857): [<ffffffff8100cc50>] restore_args+0x0/0x30 [ 316.756006] hardirqs last disabled at (269858): [<ffffffff8100bf6a>] save_args+0x6a/0x70 [ 316.756006] softirqs last enabled at (269856): [<ffffffff81055d9e>] __do_softirq+0x19e/0x1f0 [ 316.756006] softirqs last disabled at (269841): [<ffffffff8100d3cc>] call_softirq+0x1c/0x50 [ 316.756006] CPU 1: [ 316.756006] Modules linked in: drm snd_hda_codec_analog snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_seq snd_timer snd_seq_device iwlagn snd iwlcore soundcore snd_page_alloc video [ 316.756006] Pid: 12497, comm: msgctl11 Not tainted 2.6.31-rc1 #33 HP Compaq 6910p [ 316.756006] RIP: 0010:[<ffffffff810804a9>] [<ffffffff810804a9>] lock_acquire+0xf9/0x120 [ 316.756006] RSP: 0000:ffff880013a9fcd8 EFLAGS: 00000246 [ 316.756006] RAX: ffff880013a7c500 RBX: ffff880013a9fd28 RCX: ffffffff81b6c928 [ 316.756006] RDX: 0000000000000002 RSI: ffffffff82130ff0 RDI: 0000000000000246 [ 316.756006] RBP: ffffffff8100cb8e R08: ffffff18f84dc1fb R09: 0000000000000001 [ 316.756006] R10: 00000000000001ce R11: 0000000000000001 R12: 0000000000000002 [ 316.756006] R13: ffff880013a7cc90 R14: 000000008107eca9 R15: ffff880013a9fd08 [ 316.756006] FS: 00007f91a8bf76f0(0000) GS:ffff88000272f000(0000) knlGS:0000000000000000 [ 316.756006] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 316.756006] CR2: 00007f91a8c079a0 CR3: 0000000013a81000 CR4: 00000000000006e0 [ 316.756006] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 316.756006] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 316.756006] Call Trace: [ 316.756006] [<ffffffff810fade9>] ? __swap_duplicate+0x59/0x1a0 [ 316.756006] [<ffffffff8158e0e6>] ? _spin_lock+0x36/0x70 [ 316.756006] [<ffffffff810fade9>] ? __swap_duplicate+0x59/0x1a0 [ 316.756006] [<ffffffff810fade9>] ? __swap_duplicate+0x59/0x1a0 [ 316.756006] [<ffffffff810faf43>] ? swapcache_prepare+0x13/0x20 [ 316.756006] [<ffffffff810fa423>] ? read_swap_cache_async+0x63/0x120 [ 316.756006] [<ffffffff810fa567>] ? swapin_readahead+0x87/0xc0 [ 316.756006] [<ffffffff810ec9f9>] ? handle_mm_fault+0x719/0x840 [ 316.756006] [<ffffffff815911cb>] ? do_page_fault+0x1cb/0x330 [ 316.756006] [<ffffffff8158e9e5>] ? page_fault+0x25/0x30 [ 316.756006] Kernel panic - not syncing: softlockup: hung tasks [ 316.756006] Pid: 12497, comm: msgctl11 Not tainted 2.6.31-rc1 #33 [ 316.756006] Call Trace: [ 316.756006] <IRQ> [<ffffffff8158a01a>] panic+0xa5/0x173 [ 316.756006] [<ffffffff8100cb8e>] ? common_interrupt+0xe/0x13 [ 316.756006] [<ffffffff81012e69>] ? sched_clock+0x9/0x10 [ 316.756006] [<ffffffff8107b745>] ? lock_release_holdtime+0x35/0x1c0 [ 316.756006] [<ffffffff8158df1b>] ? _spin_unlock+0x2b/0x40 [ 316.756006] [<ffffffff810a733d>] softlockup_tick+0x1ad/0x1e0 [ 316.756006] [<ffffffff8105b91d>] run_local_timers+0x1d/0x30 [ 316.756006] [<ffffffff8105b96c>] update_process_times+0x3c/0x80 [ 316.756006] [<ffffffff810773fc>] tick_periodic+0x2c/0x80 [ 316.756006] [<ffffffff81077476>] tick_handle_periodic+0x26/0x90 [ 316.756006] [<ffffffff81077848>] tick_do_broadcast+0x88/0x90 [ 316.756006] [<ffffffff810779a9>] tick_do_periodic_broadcast+0x39/0x50 [ 316.756006] [<ffffffff81077f34>] tick_handle_periodic_broadcast+0x14/0x50 [ 316.756006] [<ffffffff8100f5ef>] timer_interrupt+0x1f/0x30 [ 316.756006] [<ffffffff810a7e70>] handle_IRQ_event+0x70/0x180 [ 316.756006] [<ffffffff810a9cf1>] handle_edge_irq+0xc1/0x160 [ 316.756006] [<ffffffff8100ee6b>] handle_irq+0x4b/0xb0 [ 316.756006] [<ffffffff8159346f>] do_IRQ+0x6f/0xf0 [ 316.756006] [<ffffffff8100cb93>] ret_from_intr+0x0/0x16 [ 316.756006] <EOI> [<ffffffff810804a9>] ? lock_acquire+0xf9/0x120 [ 316.756006] [<ffffffff810fade9>] ? __swap_duplicate+0x59/0x1a0 [ 316.756006] [<ffffffff8158e0e6>] ? _spin_lock+0x36/0x70 [ 316.756006] [<ffffffff810fade9>] ? __swap_duplicate+0x59/0x1a0 [ 316.756006] [<ffffffff810fade9>] ? __swap_duplicate+0x59/0x1a0 [ 316.756006] [<ffffffff810faf43>] ? swapcache_prepare+0x13/0x20 [ 316.756006] [<ffffffff810fa423>] ? read_swap_cache_async+0x63/0x120 [ 316.756006] [<ffffffff810fa567>] ? swapin_readahead+0x87/0xc0 [ 316.756006] [<ffffffff810ec9f9>] ? handle_mm_fault+0x719/0x840 [ 316.756006] [<ffffffff815911cb>] ? do_page_fault+0x1cb/0x330 [ 316.756006] [<ffffffff8158e9e5>] ? page_fault+0x25/0x30 [ 316.756006] Rebooting in 100 seconds..
--- mm/page_alloc.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)
--- linux.orig/mm/page_alloc.c +++ linux/mm/page_alloc.c @@ -1721,6 +1721,30 @@ gfp_to_alloc_flags(gfp_t gfp_mask) return alloc_flags; } +static bool too_many_isolated(struct zonelist *zonelist, + enum zone_type high_zoneidx, nodemask_t *nodemask) +{ + unsigned long nr_inactive = 0; + unsigned long nr_isolated = 0; + struct zoneref *z; + struct zone *zone; + + for_each_zone_zonelist_nodemask(zone, z, zonelist, + high_zoneidx, nodemask) { + if (!populated_zone(zone)) + continue; + + nr_inactive += zone_page_state(zone, NR_INACTIVE_FILE); + nr_isolated += zone_page_state(zone, NR_ISOLATED_FILE); + if (nr_swap_pages) { + nr_inactive += zone_page_state(zone, NR_INACTIVE_ANON); + nr_isolated += zone_page_state(zone, NR_ISOLATED_ANON); + } + } + + return nr_isolated > nr_inactive; +} + static inline struct page * __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, struct zonelist *zonelist, enum zone_type high_zoneidx, @@ -1789,6 +1813,11 @@ rebalance: if (p->flags & PF_MEMALLOC) goto nopage; + if (too_many_isolated(zonelist, high_zoneidx, nodemask)) { + schedule_timeout_uninterruptible(HZ/10); + goto restart; + } + /* Try direct reclaim and then allocating */ page = __alloc_pages_direct_reclaim(gfp_mask, order, zonelist, high_zoneidx,
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