From: Andi Kleen <andi@firstfloor.org>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
Andrea Arcangeli <aarcange@redhat.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>,
Michal Hocko <mhocko@suse.cz>,
Ebru Akagunduz <ebru.akagunduz@gmail.com>,
Alex Thorlton <athorlton@sgi.com>,
David Rientjes <rientjes@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [RFC 0/6] the big khugepaged redesign
Date: Mon, 23 Feb 2015 13:03:22 -0800 [thread overview]
Message-ID: <87lhjouyqt.fsf@tassilo.jf.intel.com> (raw)
In-Reply-To: <1424696322-21952-1-git-send-email-vbabka@suse.cz> (Vlastimil Babka's message of "Mon, 23 Feb 2015 13:58:36 +0100")
Vlastimil Babka <vbabka@suse.cz> writes:
> This has been already discussed as a good
> idea and a RFC has been posted by Alex Thorlton last October [5].
In my opinion it's a very bad idea. It heavily penalizes the single
threaded application case, which is quite important. And it
would likely lead to even larger latencies on the application
base, even for the multithreaded case, as there is no good way
anymore to hide blocking latencies in the process.
The current single thead khugepaged has various issues, but this would
just make it much worse.
IMHO it's useless to do much here without a lot of data first
to identify the actual problems. Doing things first without analysis
first seems totally backwards.
-Andi
--
ak@linux.intel.com -- Speaking for myself only
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next prev parent reply other threads:[~2015-02-23 21:03 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-23 12:58 Vlastimil Babka
2015-02-23 12:58 ` [RFC 1/6] mm, thp: stop preallocating hugepages in khugepaged Vlastimil Babka
2015-02-23 12:58 ` [RFC 2/6] mm, thp: make khugepaged check for THP allocability before scanning Vlastimil Babka
2015-02-23 12:58 ` [RFC 3/6] mm, thp: try fault allocations only if we expect them to succeed Vlastimil Babka
2015-02-23 12:58 ` [RFC 4/6] mm, thp: move collapsing from khugepaged to task_work context Vlastimil Babka
2015-02-23 14:25 ` Peter Zijlstra
2015-02-23 12:58 ` [RFC 5/6] mm, thp: wakeup khugepaged when THP allocation fails Vlastimil Babka
2015-02-23 12:58 ` [RFC 6/6] mm, thp: remove no longer needed khugepaged code Vlastimil Babka
2015-02-23 21:03 ` Andi Kleen [this message]
2015-02-23 22:46 ` [RFC 0/6] the big khugepaged redesign Davidlohr Bueso
2015-02-23 22:56 ` Andrew Morton
2015-02-23 22:58 ` Sasha Levin
2015-02-24 10:32 ` Vlastimil Babka
2015-02-24 11:24 ` Andrea Arcangeli
2015-02-24 11:45 ` Andrea Arcangeli
2015-02-25 12:42 ` Vlastimil Babka
2015-03-05 16:30 ` Vlastimil Babka
2015-03-05 16:52 ` Andres Freund
2015-03-05 17:01 ` Vlastimil Babka
2015-03-05 17:07 ` Andres Freund
2015-03-06 0:21 ` Andres Freund
2015-03-06 7:50 ` Vlastimil Babka
2015-03-09 3:17 ` Vlastimil Babka
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