From: Yunfeng Ye <yeyunfeng@huawei.com>
To: John Hubbard <jhubbard@nvidia.com>, <cl@linux.com>,
<penberg@kernel.org>, <rientjes@google.com>,
<iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>, <vbabka@suse.cz>,
<linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>
Cc: <songmuchun@bytedance.com>, <willy@infradead.org>,
<wuxu.wu@huawei.com>, Hewenliang <hewenliang4@huawei.com>
Subject: Re: [PATCH v2] mm, slub: emit the "free" trace report before freeing memory in kmem_cache_free()
Date: Wed, 3 Nov 2021 11:41:26 +0800 [thread overview]
Message-ID: <a0217bfe-87da-8f2a-6a40-edd061baad26@huawei.com> (raw)
In-Reply-To: <6ba0f3d0-cf93-9fb3-d691-962e1cb65eb4@nvidia.com>
On 2021/11/3 2:37, John Hubbard wrote:
> On 11/2/21 04:43, Yunfeng Ye wrote:
>> After the memory is freed, it can be immediately allocated by other
>> CPUs, before the "free" trace report has been emitted. This causes
>> inaccurate traces.
>>
>> For example, if the following sequence of events occurs:
>>
>> CPU 0 CPU 1
>>
>> (1) alloc xxxxxx
>> (2) free xxxxxx
>> (3) alloc xxxxxx
>> (4) free xxxxxx
>>
>> Then they will be inaccurately reported via tracing, so that they appear
>> to have happened in this order:
>>
>> CPU 0 CPU 1
>>
>> (1) alloc xxxxxx
>> (2) alloc xxxxxx
>> (3) free xxxxxx
>> (4) free xxxxxx
>>
>> This makes it look like CPU 1 somehow managed to allocate mmemory that
>
>
> I see I created a typo for you, sorry about that: s/mmemory/memory/
>
> But anyway, the wording looks good now. Please feel free to add:
>
> Reviewed-by: John Hubbard <jhubbard@nvidia.com>
>
Ok, I will fix the typo in the v3 patch.
Thanks.
>
> thanks,
prev parent reply other threads:[~2021-11-03 3:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-02 11:43 Yunfeng Ye
2021-11-02 13:53 ` Tang Yizhou
2021-11-02 14:39 ` Vlastimil Babka
2021-11-03 3:39 ` Yunfeng Ye
2021-11-02 18:37 ` John Hubbard
2021-11-03 3:41 ` Yunfeng Ye [this message]
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