From: David Hildenbrand <david@redhat.com>
To: Miaohe Lin <linmiaohe@huawei.com>,
Mike Kravetz <mike.kravetz@oracle.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] mm/hugetlb: avoid unnecessary hugetlb_acct_memory() call
Date: Fri, 15 Jan 2021 09:47:44 +0100 [thread overview]
Message-ID: <d5ea6179-7e0d-7727-50d2-efa694ba84b3@redhat.com> (raw)
In-Reply-To: <9841241e-eb8f-9b49-8d2d-d84effda8ba4@huawei.com>
On 15.01.21 03:04, Miaohe Lin wrote:
> Hi:
>
> On 2021/1/15 3:16, Mike Kravetz wrote:
>> On 1/14/21 4:32 AM, David Hildenbrand wrote:
>>> On 14.01.21 12:31, Miaohe Lin wrote:
>>>> When gbl_reserve is 0, hugetlb_acct_memory() will do nothing except holding
>>>> and releasing hugetlb_lock.
>>>
>>> So, what's the deal then? Adding more code?
>>>
>>> If this is a performance improvement, we should spell it out. Otherwise
>>> I don't see a real benefit of this patch.
>>>
>>
>> Thanks for finding/noticing this.
>>
>> As David points out, the commit message should state that this is a
>> performance improvement. Mention that such a change avoids an unnecessary
>> hugetlb_lock lock/unlock cycle. You can also mention that this unnecessary
>> lock cycle is happening on 'most' hugetlb munmap operations.
>>
>
> My bad. I should spell this out explicitly. Many thanks for both of you.
With the "lock cycle is happening on 'most' hugetlb munmap operations"
part added
Reviewed-by: David Hildenbrand <david@redhat.com>
Thanks!
--
Thanks,
David / dhildenb
prev parent reply other threads:[~2021-01-15 8:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-14 11:31 [PATCH] mm/hugetlb: avoid unnecessary hugetlb_acct_memory() call Miaohe Lin
2021-01-14 12:32 ` David Hildenbrand
2021-01-14 19:16 ` Mike Kravetz
2021-01-15 2:04 ` Miaohe Lin
2021-01-15 8:47 ` David Hildenbrand [this message]
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