linux-mm.kvack.org archive mirror
 help / color / mirror / Atom feed
From: Oscar Salvador <osalvador@suse.de>
To: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>,
	akpm@linux-foundation.org, david@redhat.com,
	anthony.yznaga@oracle.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm,memory_hotplug: Explicitly pass the head to isolate_huge_page
Date: Wed, 13 Feb 2019 16:15:50 +0100	[thread overview]
Message-ID: <20190213151547.cwaqptreai43s65j@d104.suse.de> (raw)
In-Reply-To: <20190213123339.GG4525@dhcp22.suse.cz>

On Wed, Feb 13, 2019 at 01:33:39PM +0100, Michal Hocko wrote:
> Why isn't our check in has_unmovable_pages sufficient?

Taking a closer look, it should be enough.
I was mainly confused by the fact that if the zone is ZONE_MOVABLE,
we do not keep checking in has_unmovable_pages():

if (zone_idx(zone) == ZONE_MOVABLE)
	continue;

But I overlooked that htlb_alloc_mask() checks whether the allocation
cand end up in a movable zone.
hugepage_movable_supported() checks that and if the hstate does not
support migration at all, we skip __GFP_MOVABLE.

So I think that the check in has_unmovable_pages() should be more than enough,
so we could strip the checks from do_migrate_ranges() and
scan_movable_pages() regarding hugepage migratability.

I will run some tests just to make sure this holds and then
I will send a patch.

Thanks
-- 
Oscar Salvador
SUSE L3


      reply	other threads:[~2019-02-13 15:15 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-08  9:06 Oscar Salvador
2019-02-11  8:58 ` David Hildenbrand
2019-02-12  8:33 ` Michal Hocko
2019-02-12 13:45   ` Oscar Salvador
2019-02-12 14:40     ` Michal Hocko
2019-02-13  0:13       ` Mike Kravetz
2019-02-13  8:13         ` Oscar Salvador
2019-02-13 12:33           ` Michal Hocko
2019-02-13 15:15             ` Oscar Salvador [this message]

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=20190213151547.cwaqptreai43s65j@d104.suse.de \
    --to=osalvador@suse.de \
    --cc=akpm@linux-foundation.org \
    --cc=anthony.yznaga@oracle.com \
    --cc=david@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@kernel.org \
    --cc=mike.kravetz@oracle.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