From: Xiongfeng Wang <wangxiongfeng2@huawei.com>
To: Nicolas Saenz Julienne <nsaenzju@redhat.com>,
<akpm@linux-foundation.org>
Cc: <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
<frederic@kernel.org>, <tglx@linutronix.de>,
<mtosatti@redhat.com>, <mgorman@suse.de>,
<linux-rt-users@vger.kernel.org>, <vbabka@suse.cz>,
<cl@linux.com>, <paulmck@kernel.org>, <willy@infradead.org>
Subject: Re: [PATCH 0/2] mm/page_alloc: Remote per-cpu lists drain support
Date: Wed, 9 Feb 2022 19:26:29 +0800 [thread overview]
Message-ID: <b2e7ea31-0a56-6415-474b-a952fb1d36ef@huawei.com> (raw)
In-Reply-To: <b5363ced8e17d07d41554da8fde06c410e6688e0.camel@redhat.com>
Hi,
On 2022/2/9 17:45, Nicolas Saenz Julienne wrote:
> Hi Xiongfeng, thanks for taking the time to look at this.
>
> On Wed, 2022-02-09 at 16:55 +0800, Xiongfeng Wang wrote:
>> Hi Nicolas,
>>
>> When I applied the patchset on the following commit and tested on QEMU, I came
>> accross the following CallTrace.
>> commit dd81e1c7d5fb126e5fbc5c9e334d7b3ec29a16a0
>>
>> I wrote a userspace application to consume the memory. When the memory is used
>> out, the OOM killer is triggered and the following Calltrace is printed. I am
>> not sure if it is related to this patchset. But when I reverted this patchset,
>> the 'NULL pointer' Calltrace didn't show.
>
> It's a silly mistake on my part, while cleaning up the code I messed up one of
> the 'struct per_cpu_pages' accessors. This should fix it:
>
> ------------------------->8-------------------------
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 0caa7155ca34..e65b991c3dc8 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -3279,7 +3279,7 @@ static void __drain_all_pages(struct zone *zone, bool force_all_cpus)
> has_pcps = true;
> } else {
> for_each_populated_zone(z) {
> - pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu);
> + pcp = per_cpu_ptr(z->per_cpu_pageset, cpu);
> lp = rcu_dereference_protected(pcp->lp,
> mutex_is_locked(&pcpu_drain_mutex));
> if (lp->count) {
I have tested it. It works well. No more 'NULL pointer' Calltrace.
Thanks,
Xiongfeng
> ------------------------->8-------------------------
>
> Thanks!
>
next prev parent reply other threads:[~2022-02-09 12:07 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-08 10:07 [PATCH 0/2] mm/page_alloc: Remote per-cpu lists drain support Nicolas Saenz Julienne
2022-02-08 10:07 ` [PATCH 1/2] mm/page_alloc: Access lists in 'struct per_cpu_pages' indirectly Nicolas Saenz Julienne
2022-03-03 14:33 ` Marcelo Tosatti
2022-02-08 10:07 ` [PATCH 2/2] mm/page_alloc: Add remote draining support to per-cpu lists Nicolas Saenz Julienne
2022-02-08 15:47 ` Marcelo Tosatti
2022-02-15 8:47 ` Nicolas Saenz Julienne
2022-02-15 17:32 ` Paul E. McKenney
2022-02-09 8:55 ` [PATCH 0/2] mm/page_alloc: Remote per-cpu lists drain support Xiongfeng Wang
2022-02-09 9:45 ` Nicolas Saenz Julienne
2022-02-09 11:26 ` Xiongfeng Wang [this message]
2022-02-09 11:36 ` Nicolas Saenz Julienne
2022-02-10 10:59 ` Xiongfeng Wang
2022-02-10 11:04 ` Nicolas Saenz Julienne
2022-03-03 11:45 ` Mel Gorman
2022-03-07 13:57 ` Nicolas Saenz Julienne
2022-03-10 16:31 ` Mel Gorman
2022-03-07 20:47 ` Marcelo Tosatti
2022-03-24 18:59 ` Nicolas Saenz Julienne
2022-03-25 10:48 ` Mel Gorman
2022-03-28 13:51 ` Nicolas Saenz Julienne
2022-03-29 9:45 ` Mel Gorman
2022-03-30 11:29 ` Nicolas Saenz Julienne
2022-03-31 15:24 ` Mel Gorman
2022-03-03 13:27 ` Vlastimil Babka
2022-03-03 14:10 ` Nicolas Saenz Julienne
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