From: David Hildenbrand <david@redhat.com>
To: Lance Yang <ioworker0@gmail.com>, akpm@linux-foundation.org
Cc: mhocko@suse.com, zokeefe@google.com, songmuchun@bytedance.com,
shy828301@gmail.com, peterx@redhat.com, minchan@kernel.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1] mm/khugepaged: bypassing unnecessary scans with MMF_DISABLE_THP check
Date: Thu, 22 Feb 2024 09:51:00 +0100 [thread overview]
Message-ID: <84fc211a-075d-44c7-a4c3-698931b6dc7c@redhat.com> (raw)
In-Reply-To: <CAK1f24nk19eciysFqvTd=rqpiKePhstDWEEQ_mvT89WCDNrWNQ@mail.gmail.com>
On 22.02.24 08:51, Lance Yang wrote:
> Hey,
>
> On an Intel Core i5 CPU, the time taken by
> khugepaged to scan the address space of
> the process, which has been set with the
> MMF_DISABLE_THP flag after being added
> to the mm_slots list, is as follows (shorter is better):
>
> VMA Count | Old | New | Change
> ---------------------------------------
> 50 | 23us | 9us | -60.9%
> 100 | 32us | 9us | -71.9%
> 200 | 44us | 9us | -79.5%
> 400 | 75us | 9us | -88.0%
> 800 | 98us | 9us | -90.8%
>
> IIUC, once the count of VMAs for the process
> exceeds page_to_scan, khugepaged needs to
> wait for scan_sleep_millisecs ms before scanning
> the next process. IMO, unnecessary scans could
> actually be skipped with a very inexpensive
> mm->flags check in this case.
FWIW
Acked-by: David Hildenbrand <david@redhat.com>
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2024-02-22 8:51 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-29 5:45 [PATCH 1/1] mm/khugepaged: bypassing unnecessary scans with MMF_DISABLE_THP check Lance Yang
2024-01-29 16:28 ` Michal Hocko
2024-01-30 2:12 ` Lance Yang
2024-01-30 3:08 ` Lance Yang
2024-01-30 9:35 ` Michal Hocko
2024-01-30 9:46 ` Lance Yang
2024-01-31 0:37 ` Lance Yang
2024-01-29 18:53 ` Yang Shi
2024-01-29 19:03 ` Zach O'Keefe
2024-01-30 2:37 ` Lance Yang
2024-01-30 2:21 ` Lance Yang
2024-01-31 9:30 ` Lance Yang
2024-01-31 20:06 ` Yang Shi
2024-02-01 1:13 ` Lance Yang
2024-02-01 18:56 ` Yang Shi
2024-02-03 3:20 ` Lance Yang
2024-02-21 22:11 ` Andrew Morton
2024-02-22 7:43 ` Lance Yang
2024-02-22 7:51 ` Lance Yang
2024-02-22 8:51 ` David Hildenbrand [this message]
2024-02-22 9:12 ` Lance Yang
2024-02-22 20:23 ` Yang Shi
2024-02-22 21:11 ` Andrew Morton
2024-02-23 7:59 ` Lance Yang
2024-02-24 1:47 ` Yang Shi
2024-02-24 1:46 ` Yang Shi
2024-02-24 3:54 ` Lance Yang
2024-02-25 4:56 ` Lance Yang
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