linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Mel Gorman <mgorman@suse.de>
Cc: Dave Chinner <david@fromorbit.com>,
	Ingo Molnar <mingo@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>,
	xfs@oss.sgi.com, ppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH 4/4] mm: numa: Slow PTE scan rate if migration failures occur
Date: Thu, 19 Mar 2015 11:09:15 -0700	[thread overview]
Message-ID: <CA+55aFwTcw2rTjPM_EOjPeKNWwdfNVazx+O=YAFXPWw1h==Tgw@mail.gmail.com> (raw)
In-Reply-To: <20150319141022.GD3087@suse.de>

On Thu, Mar 19, 2015 at 7:10 AM, Mel Gorman <mgorman@suse.de> wrote:
> -       if (!pmd_dirty(pmd))
> +       /* See similar comment in do_numa_page for explanation */
> +       if (!(vma->vm_flags & VM_WRITE))

Yeah, that would certainly be a whole lot more obvious than all the
"if this particular pte/pmd looks like X" tests.

So that, together with scanning rate improvements (this *does* seem to
be somewhat chaotic, so it's quite possible that the current scanning
rate thing is just fairly unstable) is likely the right thing. I'd
just like to _understand_ why that write/dirty bit makes such a
difference. I thought I understood what was going on, and was happy,
and then Dave come with his crazy numbers.

Damn you Dave, and damn your numbers and "facts" and stuff. Sometimes
I much prefer ignorant bliss.

                           Linus

  reply	other threads:[~2015-03-19 18:09 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-07 15:20 [RFC PATCH 0/4] Automatic NUMA balancing and PROT_NONE handling followup v2r8 Mel Gorman
2015-03-07 15:20 ` [PATCH 1/4] mm: thp: Return the correct value for change_huge_pmd Mel Gorman
2015-03-07 20:13   ` Linus Torvalds
2015-03-07 20:31   ` Linus Torvalds
2015-03-07 20:56     ` Mel Gorman
2015-03-07 15:20 ` [PATCH 2/4] mm: numa: Remove migrate_ratelimited Mel Gorman
2015-03-07 15:20 ` [PATCH 3/4] mm: numa: Mark huge PTEs young when clearing NUMA hinting faults Mel Gorman
2015-03-07 18:33   ` Linus Torvalds
2015-03-07 18:42     ` Linus Torvalds
2015-03-07 15:20 ` [PATCH 4/4] mm: numa: Slow PTE scan rate if migration failures occur Mel Gorman
2015-03-07 16:36   ` Ingo Molnar
2015-03-07 17:37     ` Mel Gorman
2015-03-08  9:54       ` Ingo Molnar
2015-03-07 19:12     ` Linus Torvalds
2015-03-08 10:02       ` Ingo Molnar
2015-03-08 18:35         ` Linus Torvalds
2015-03-08 18:46           ` Linus Torvalds
2015-03-09 11:29           ` Dave Chinner
2015-03-09 16:52             ` Linus Torvalds
2015-03-09 19:19               ` Dave Chinner
2015-03-10 23:55                 ` Linus Torvalds
2015-03-12 13:10                   ` Mel Gorman
2015-03-12 16:20                     ` Linus Torvalds
2015-03-12 18:49                       ` Mel Gorman
2015-03-17  7:06                         ` Dave Chinner
2015-03-17 16:53                           ` Linus Torvalds
2015-03-17 20:51                             ` Dave Chinner
2015-03-17 21:30                               ` Linus Torvalds
2015-03-17 22:08                                 ` Dave Chinner
2015-03-18 16:08                                   ` Linus Torvalds
2015-03-18 17:31                                     ` Linus Torvalds
2015-03-18 22:23                                       ` Dave Chinner
2015-03-19 14:10                                       ` Mel Gorman
2015-03-19 18:09                                         ` Linus Torvalds [this message]
2015-03-19 21:41                                       ` Linus Torvalds
2015-03-19 22:41                                         ` Dave Chinner
2015-03-19 23:05                                           ` Linus Torvalds
2015-03-19 23:23                                             ` Dave Chinner
2015-03-20  0:23                                             ` Dave Chinner
2015-03-20  1:29                                               ` Linus Torvalds
2015-03-20  4:13                                                 ` Dave Chinner
2015-03-20 17:02                                                   ` Linus Torvalds
2015-03-23 12:01                                                     ` Mel Gorman
2015-03-20 10:12                                                 ` Mel Gorman
2015-03-20  9:56                                             ` Mel Gorman
2015-03-08 20:40         ` Mel Gorman
2015-03-09 21:02           ` Mel Gorman
2015-03-10 13:08             ` Mel Gorman
2015-03-08  9:41   ` Ingo Molnar

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CA+55aFwTcw2rTjPM_EOjPeKNWwdfNVazx+O=YAFXPWw1h==Tgw@mail.gmail.com' \
    --to=torvalds@linux-foundation.org \
    --cc=akpm@linux-foundation.org \
    --cc=aneesh.kumar@linux.vnet.ibm.com \
    --cc=david@fromorbit.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=mgorman@suse.de \
    --cc=mingo@kernel.org \
    --cc=xfs@oss.sgi.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).