From: Alex Shi <alex.shi@linux.alibaba.com>
To: Alexander Duyck <alexander.duyck@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@techsingularity.net>,
Tejun Heo <tj@kernel.org>, Hugh Dickins <hughd@google.com>,
Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
Daniel Jordan <daniel.m.jordan@oracle.com>,
Yang Shi <yang.shi@linux.alibaba.com>,
Matthew Wilcox <willy@infradead.org>,
Johannes Weiner <hannes@cmpxchg.org>,
kbuild test robot <lkp@intel.com>, linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
cgroups@vger.kernel.org, Shakeel Butt <shakeelb@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Wei Yang <richard.weiyang@gmail.com>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Rong Chen <rong.a.chen@intel.com>,
Michal Hocko <mhocko@kernel.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>
Subject: Re: [PATCH v17 17/21] mm/lru: replace pgdat lru_lock with lruvec lock
Date: Tue, 28 Jul 2020 19:19:52 +0800 [thread overview]
Message-ID: <ccd01046-451c-463d-7c5d-9c32794f4b1e@linux.alibaba.com> (raw)
In-Reply-To: <CAKgT0UdaW4Rf43yULhQBuP07vQgmoPbaWHGKv1Z7fEPP6jH83w@mail.gmail.com>
在 2020/7/28 上午7:34, Alexander Duyck 写道:
>> @@ -1876,6 +1876,12 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
>> * list_add(&page->lru,)
>> * list_add(&page->lru,) //corrupt
>> */
>> + new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
>> + if (new_lruvec != lruvec) {
>> + if (lruvec)
>> + spin_unlock_irq(&lruvec->lru_lock);
>> + lruvec = lock_page_lruvec_irq(page);
>> + }
>> SetPageLRU(page);
>>
>> if (unlikely(put_page_testzero(page))) {
> I was going through the code of the entire patch set and I noticed
> these changes in move_pages_to_lru. What is the reason for adding the
> new_lruvec logic? My understanding is that we are moving the pages to
> the lruvec provided are we not?If so why do we need to add code to get
> a new lruvec? The code itself seems to stand out from the rest of the
> patch as it is introducing new code instead of replacing existing
> locking code, and it doesn't match up with the description of what
> this function is supposed to do since it changes the lruvec.
this new_lruvec is the replacement of removed line, as following code:
>> - lruvec = mem_cgroup_page_lruvec(page, pgdat);
This recheck is for the page move the root memcg, otherwise it cause the bug:
[ 2081.240795] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 2081.248125] #PF: supervisor read access in kernel mode
[ 2081.253627] #PF: error_code(0x0000) - not-present page
[ 2081.259124] PGD 8000000044cb0067 P4D 8000000044cb0067 PUD 95c9067 PMD 0
[ 2081.266193] Oops: 0000 [#1] PREEMPT SMP PTI
[ 2081.270740] CPU: 5 PID: 131 Comm: kswapd0 Kdump: loaded Tainted: G W 5.8.0-rc6-00025-gc708f8a0db47 #45
[ 2081.281960] Hardware name: Alibaba X-Dragon CN 01/20G4B, BIOS 1ALSP016 05/21/2018
[ 2081.290054] RIP: 0010:do_raw_spin_trylock+0x5/0x40
[ 2081.295209] Code: 76 82 48 89 df e8 bb fe ff ff eb 8c 89 c6 48 89 df e8 4f dd ff ff 66 90 eb 8b 90 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 <8b> 07 85 c0 75 28 ba 01 00 00 00 f0 0f b1 17 75 1d 65 8b 05 03 6a
[ 2081.314832] RSP: 0018:ffffc900002ebac8 EFLAGS: 00010082
[ 2081.320410] RAX: 0000000000000000 RBX: 0000000000000018 RCX: 0000000000000000
[ 2081.327907] RDX: ffff888035833480 RSI: 0000000000000000 RDI: 0000000000000000
[ 2081.335407] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
[ 2081.342907] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
[ 2081.350405] R13: dead000000000100 R14: 0000000000000000 R15: ffffc900002ebbb0
[ 2081.357908] FS: 0000000000000000(0000) GS:ffff88807a200000(0000) knlGS:0000000000000000
[ 2081.366619] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2081.372717] CR2: 0000000000000000 CR3: 0000000031228005 CR4: 00000000003606e0
[ 2081.380215] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 2081.387713] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 2081.395198] Call Trace:
[ 2081.398008] _raw_spin_lock_irq+0x47/0x80
[ 2081.402387] ? move_pages_to_lru+0x566/0xb80
[ 2081.407028] move_pages_to_lru+0x566/0xb80
[ 2081.411495] shrink_active_list+0x355/0xa70
[ 2081.416054] shrink_lruvec+0x4f7/0x810
[ 2081.420176] ? mem_cgroup_iter+0xb6/0x410
[ 2081.424558] shrink_node+0x1cc/0x8d0
[ 2081.428510] balance_pgdat+0x3cf/0x760
[ 2081.432634] kswapd+0x232/0x660
[ 2081.436147] ? finish_wait+0x80/0x80
[ 2081.440093] ? balance_pgdat+0x760/0x760
[ 2081.444382] kthread+0x17e/0x1b0
[ 2081.447975] ? kthread_park+0xc0/0xc0
[ 2081.452005] ret_from_fork+0x22/0x30
Thanks!
Alex
>
>> @@ -1883,16 +1889,15 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
>> __ClearPageActive(page);
>>
>> if (unlikely(PageCompound(page))) {
>> - spin_unlock_irq(&pgdat->lru_lock);
>> + spin_unlock_irq(&lruvec->lru_lock);
>> destroy_compound_page(page);
>> - spin_lock_irq(&pgdat->lru_lock);
>> + spin_lock_irq(&lruvec->lru_lock);
>> } else
>> list_add(&page->lru, &pages_to_free);
>>
>> continue;
>> }
>>
>> - lruvec = mem_cgroup_page_lruvec(page, pgdat);
>> lru = page_lru(page);
>> nr_pages = hpage_nr_pages(page);
next prev parent reply other threads:[~2020-07-28 11:20 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-25 12:59 [PATCH v17 00/21] per memcg lru lock Alex Shi
2020-07-25 12:59 ` [PATCH v17 01/21] mm/vmscan: remove unnecessary lruvec adding Alex Shi
2020-08-06 3:47 ` Alex Shi
2020-07-25 12:59 ` [PATCH v17 02/21] mm/page_idle: no unlikely double check for idle page counting Alex Shi
2020-07-25 12:59 ` [PATCH v17 03/21] mm/compaction: correct the comments of compact_defer_shift Alex Shi
2020-07-27 17:29 ` Alexander Duyck
2020-07-28 11:59 ` Alex Shi
2020-07-28 14:17 ` Alexander Duyck
2020-07-25 12:59 ` [PATCH v17 04/21] mm/compaction: rename compact_deferred as compact_should_defer Alex Shi
2020-07-25 12:59 ` [PATCH v17 05/21] mm/thp: move lru_add_page_tail func to huge_memory.c Alex Shi
2020-07-25 12:59 ` [PATCH v17 06/21] mm/thp: clean up lru_add_page_tail Alex Shi
2020-07-25 12:59 ` [PATCH v17 07/21] mm/thp: remove code path which never got into Alex Shi
2020-07-25 12:59 ` [PATCH v17 08/21] mm/thp: narrow lru locking Alex Shi
2020-07-25 12:59 ` [PATCH v17 09/21] mm/memcg: add debug checking in lock_page_memcg Alex Shi
2020-07-25 12:59 ` [PATCH v17 10/21] mm/swap: fold vm event PGROTATED into pagevec_move_tail_fn Alex Shi
2020-07-25 12:59 ` [PATCH v17 11/21] mm/lru: move lru_lock holding in func lru_note_cost_page Alex Shi
2020-08-05 21:18 ` Alexander Duyck
2020-07-25 12:59 ` [PATCH v17 12/21] mm/lru: move lock into lru_note_cost Alex Shi
2020-07-25 12:59 ` [PATCH v17 13/21] mm/lru: introduce TestClearPageLRU Alex Shi
2020-07-29 3:53 ` Alex Shi
2020-08-05 22:43 ` Alexander Duyck
2020-08-06 1:54 ` Alex Shi
2020-08-06 14:41 ` Alexander Duyck
2020-07-25 12:59 ` [PATCH v17 14/21] mm/compaction: do page isolation first in compaction Alex Shi
2020-08-04 21:35 ` Alexander Duyck
2020-08-06 18:38 ` Alexander Duyck
2020-08-07 3:24 ` Alex Shi
2020-08-07 14:51 ` Alexander Duyck
2020-08-10 13:10 ` Alex Shi
2020-08-10 14:41 ` Alexander Duyck
2020-08-11 8:22 ` Alex Shi
2020-08-11 14:47 ` Alexander Duyck
2020-08-12 11:43 ` Alex Shi
2020-08-12 12:16 ` Alex Shi
2020-08-12 16:51 ` Alexander Duyck
2020-08-13 1:46 ` Alex Shi
2020-08-13 2:17 ` Alexander Duyck
2020-08-13 3:52 ` Alex Shi
2020-08-13 4:02 ` [RFC PATCH 0/3] " Alexander Duyck
2020-08-13 4:02 ` [RFC PATCH 1/3] mm: Drop locked from isolate_migratepages_block Alexander Duyck
2020-08-13 6:56 ` Alex Shi
2020-08-13 14:32 ` Alexander Duyck
2020-08-14 7:25 ` Alex Shi
2020-08-13 7:44 ` Alex Shi
2020-08-13 14:26 ` Alexander Duyck
2020-08-13 4:02 ` [RFC PATCH 2/3] mm: Drop use of test_and_set_skip in favor of just setting skip Alexander Duyck
2020-08-14 7:19 ` Alex Shi
2020-08-14 14:24 ` Alexander Duyck
2020-08-14 21:15 ` Alexander Duyck
2020-08-15 9:49 ` Alex Shi
2020-08-17 15:38 ` Alexander Duyck
2020-08-18 6:50 ` Alex Shi
2020-08-13 4:02 ` [RFC PATCH 3/3] mm: Identify compound pages sooner in isolate_migratepages_block Alexander Duyck
2020-08-14 7:20 ` Alex Shi
2020-08-17 22:58 ` [PATCH v17 14/21] mm/compaction: do page isolation first in compaction Alexander Duyck
2020-07-25 12:59 ` [PATCH v17 15/21] mm/thp: add tail pages into lru anyway in split_huge_page() Alex Shi
2020-07-25 12:59 ` [PATCH v17 16/21] mm/swap: serialize memcg changes in pagevec_lru_move_fn Alex Shi
2020-07-25 12:59 ` [PATCH v17 17/21] mm/lru: replace pgdat lru_lock with lruvec lock Alex Shi
2020-07-27 23:34 ` Alexander Duyck
2020-07-28 7:15 ` Alex Shi
2020-07-28 11:19 ` Alex Shi [this message]
2020-07-28 14:54 ` Alexander Duyck
2020-07-29 1:00 ` Alex Shi
2020-07-29 1:27 ` Alexander Duyck
2020-07-29 2:27 ` Alex Shi
2020-07-28 15:39 ` Alex Shi
2020-07-28 15:55 ` Alexander Duyck
2020-07-29 0:48 ` Alex Shi
2020-07-29 3:54 ` Alex Shi
2020-08-06 7:41 ` Alex Shi
2020-07-25 12:59 ` [PATCH v17 18/21] mm/lru: introduce the relock_page_lruvec function Alex Shi
2020-07-29 17:52 ` Alexander Duyck
2020-07-30 6:08 ` Alex Shi
2020-07-31 14:20 ` Alexander Duyck
2020-07-31 21:14 ` [PATCH RFC] mm: Add function for testing if the current lruvec lock is valid alexander.h.duyck
2020-07-31 23:54 ` Alex Shi
2020-08-02 18:20 ` Alexander Duyck
2020-08-04 6:13 ` Alex Shi
2020-07-25 12:59 ` [PATCH v17 19/21] mm/vmscan: use relock for move_pages_to_lru Alex Shi
2020-08-03 22:49 ` Alexander Duyck
2020-08-04 6:23 ` Alex Shi
2020-07-25 12:59 ` [PATCH v17 20/21] mm/pgdat: remove pgdat lru_lock Alex Shi
2020-08-03 22:42 ` Alexander Duyck
2020-08-03 22:45 ` Alexander Duyck
2020-08-04 6:22 ` Alex Shi
2020-07-25 12:59 ` [PATCH v17 21/21] mm/lru: revise the comments of lru_lock Alex Shi
2020-08-03 22:37 ` Alexander Duyck
2020-08-04 10:04 ` Alex Shi
2020-08-04 14:29 ` Alexander Duyck
2020-08-06 1:39 ` Alex Shi
2020-08-06 16:27 ` Alexander Duyck
2020-07-27 5:40 ` [PATCH v17 00/21] per memcg lru lock Alex Shi
2020-07-29 14:49 ` Alex Shi
2020-07-29 18:06 ` Hugh Dickins
2020-07-30 2:16 ` Alex Shi
2020-08-03 15:07 ` Michal Hocko
2020-08-04 6:14 ` Alex Shi
2020-07-31 21:31 ` Alexander Duyck
2020-08-04 8:36 ` Alex Shi
2020-08-04 8:36 ` Alex Shi
2020-08-04 8:37 ` Alex Shi
2020-08-04 8:37 ` Alex Shi
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