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From: Qian Cai <quic_qiancai@quicinc.com>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	Nicolas Saenz Julienne <nsaenzju@redhat.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	Michal Hocko <mhocko@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>, <kafai@fb.com>,
	<kpsingh@kernel.org>
Subject: Re: [PATCH 0/6] Drain remote per-cpu directly v3
Date: Thu, 19 May 2022 17:05:04 -0400	[thread overview]
Message-ID: <YoaxAMvQwHzDPxyi@qian> (raw)
In-Reply-To: <20220519191524.GC1790663@paulmck-ThinkPad-P17-Gen-1>

On Thu, May 19, 2022 at 12:15:24PM -0700, Paul E. McKenney wrote:
> Is the task doing offline_pages()->synchronize_rcu() doing this
> repeatedly?  Or is there a stalled RCU grace period?  (From what
> I can see, offline_pages() is not doing huge numbers of calls to
> synchronize_rcu() in any of its loops, but I freely admit that I do not
> know this code.)

Yes, we are running into an endless loop in isolate_single_pageblock().
There was a similar issue happened not long ago, so I am wondering if we
did not solve it entirely then. Anyway, I will continue the thread over
there.

https://lore.kernel.org/all/YoavU%2F+NfQIzQiDF@qian/

> Or is it possible that reverting those three patches simply decreases
> the probability of failure, rather than eliminating the failure?
> Such a decrease could be due to many things, for example, changes to
> offsets and sizes of data structures.

Entirely possible. Sorry for the false alarm.

> Do you ever see RCU CPU stall warnings?

No.

  reply	other threads:[~2022-05-19 21:05 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-12  8:50 [PATCH 0/6] Drain remote per-cpu directly v3 Mel Gorman
2022-05-12  8:50 ` [PATCH 1/6] mm/page_alloc: Add page->buddy_list and page->pcp_list Mel Gorman
2022-05-13 11:59   ` Nicolas Saenz Julienne
2022-05-19  9:36   ` Vlastimil Babka
2022-05-12  8:50 ` [PATCH 2/6] mm/page_alloc: Use only one PCP list for THP-sized allocations Mel Gorman
2022-05-19  9:45   ` Vlastimil Babka
2022-05-12  8:50 ` [PATCH 3/6] mm/page_alloc: Split out buddy removal code from rmqueue into separate helper Mel Gorman
2022-05-13 12:01   ` Nicolas Saenz Julienne
2022-05-19  9:52   ` Vlastimil Babka
2022-05-23 16:09   ` Qais Yousef
2022-05-24 11:55     ` Mel Gorman
2022-05-25 11:23       ` Qais Yousef
2022-05-12  8:50 ` [PATCH 4/6] mm/page_alloc: Remove unnecessary page == NULL check in rmqueue Mel Gorman
2022-05-13 12:03   ` Nicolas Saenz Julienne
2022-05-19 10:57   ` Vlastimil Babka
2022-05-19 12:13     ` Mel Gorman
2022-05-19 12:26       ` Vlastimil Babka
2022-05-12  8:50 ` [PATCH 5/6] mm/page_alloc: Protect PCP lists with a spinlock Mel Gorman
2022-05-13 12:22   ` Nicolas Saenz Julienne
2022-05-12  8:50 ` [PATCH 6/6] mm/page_alloc: Remotely drain per-cpu lists Mel Gorman
2022-05-12 19:37   ` Andrew Morton
2022-05-13 15:04     ` Mel Gorman
2022-05-13 15:19       ` Nicolas Saenz Julienne
2022-05-13 18:23         ` Mel Gorman
2022-05-17 12:57           ` Mel Gorman
2022-05-12 19:43 ` [PATCH 0/6] Drain remote per-cpu directly v3 Andrew Morton
2022-05-13 14:23   ` Mel Gorman
2022-05-13 19:38     ` Andrew Morton
2022-05-16 10:53       ` Mel Gorman
2022-05-13 12:24 ` Nicolas Saenz Julienne
2022-05-17 23:35 ` Qian Cai
2022-05-18 12:51   ` Mel Gorman
2022-05-18 16:27     ` Qian Cai
2022-05-18 17:15       ` Paul E. McKenney
2022-05-19 13:29         ` Qian Cai
2022-05-19 19:15           ` Paul E. McKenney
2022-05-19 21:05             ` Qian Cai [this message]
2022-05-19 21:29               ` Paul E. McKenney
2022-05-18 17:26   ` Marcelo Tosatti
2022-05-18 17:44     ` Marcelo Tosatti
2022-05-18 18:01 ` Nicolas Saenz Julienne
2022-05-26 17:19 ` Qian Cai
2022-05-27  8:39   ` Mel Gorman
2022-05-27 12:58     ` Qian Cai

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