From: "Yin, Fengwei" <fengwei.yin@intel.com>
To: <kirill@shutemov.name>
Cc: <linux-mm@kvack.org>, <akpm@linux-foundation.org>,
<willy@infradead.org>, <yuzhao@google.com>,
<ryan.roberts@arm.com>, <ying.huang@intel.com>
Subject: Re: [PATCH v3 1/2] THP: avoid lock when check whether THP is in deferred list
Date: Fri, 5 May 2023 09:09:31 +0800 [thread overview]
Message-ID: <c11f2be9-c07d-f751-a9bf-5e83d6c5bb6a@intel.com> (raw)
In-Reply-To: <20230504114827.tkvvlmpo33p2jpc4@box.shutemov.name>
Hi Kirill,
On 5/4/2023 7:48 PM, kirill@shutemov.name wrote:
> On Sat, Apr 29, 2023 at 04:27:58PM +0800, Yin Fengwei wrote:
>> free_transhuge_page() acquires split queue lock then check
>> whether the THP was added to deferred list or not. It brings
>> high deferred queue lock contention.
>>
>> It's safe to check whether the THP is in deferred list or not
>> without holding the deferred queue lock in free_transhuge_page()
>> because when code hit free_transhuge_page(), there is no one
>> tries to add the folio to _deferred_list.
>>
>> Running page_fault1 of will-it-scale + order 2 folio for anonymous
>> mapping with 96 processes on an Ice Lake 48C/96T test box, we could
>> see the 61% split_queue_lock contention:
>> - 63.02% 0.01% page_fault1_pro [kernel.kallsyms] [k] free_transhuge_page
>> - 63.01% free_transhuge_page
>> + 62.91% _raw_spin_lock_irqsave
>>
>> With this patch applied, the split_queue_lock contention is less
>> than 1%.
>>
>> Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
>
> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Thanks a lot for the reviewing.
Regards
Yin, Fengwei
>
next prev parent reply other threads:[~2023-05-05 1:09 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-29 8:27 [PATCH v3 0/2] Reduce lock contention related with large folio Yin Fengwei
2023-04-29 8:27 ` [PATCH v3 1/2] THP: avoid lock when check whether THP is in deferred list Yin Fengwei
2023-05-04 11:48 ` kirill
2023-05-05 1:09 ` Yin, Fengwei [this message]
2023-05-29 2:58 ` Yin Fengwei
2023-05-05 0:52 ` Huang, Ying
2023-05-05 1:09 ` Yin, Fengwei
2023-04-29 8:27 ` [PATCH v3 2/2] lru: allow large batched add large folio to lru list Yin Fengwei
2023-04-29 22:35 ` Matthew Wilcox
2023-05-01 5:52 ` Yin, Fengwei
2023-05-05 5:51 ` Yin, Fengwei
2023-05-15 2:14 ` Yin, Fengwei
2023-06-20 3:22 ` Matthew Wilcox
2023-06-20 4:39 ` Yin Fengwei
2023-06-20 8:01 ` Yin Fengwei
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