From: Mike Kravetz <mike.kravetz@oracle.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Hillf Danton <hdanton@sina.com>, Michal Hocko <mhocko@kernel.org>,
Mel Gorman <mgorman@suse.de>, Vlastimil Babka <vbabka@suse.cz>,
Johannes Weiner <hannes@cmpxchg.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mike Kravetz <mike.kravetz@oracle.com>
Subject: [RFC PATCH 0/3] fix hugetlb page allocation stalls
Date: Wed, 24 Jul 2019 10:50:11 -0700 [thread overview]
Message-ID: <20190724175014.9935-1-mike.kravetz@oracle.com> (raw)
Allocation of hugetlb pages via sysctl or procfs can stall for minutes
or hours. A simple example on a two node system with 8GB of memory is
as follows:
echo 4096 > /sys/devices/system/node/node1/hugepages/hugepages-2048kB/nr_hugepages
echo 4096 > /proc/sys/vm/nr_hugepages
Obviously, both allocation attempts will fall short of their 8GB goal.
However, one or both of these commands may stall and not be interruptible.
The issues were discussed in this thread [1].
This series attempts to address the issues causing the stalls. There are
two distinct issues, and an optimization. For the reclaim and compaction
issues, suggestions were made to simply remove some existing code. However,
the impact of such changes would be hard to address. This series takes a
more conservative approach in an attempt to minimally impact existing
workloads. The question of which approach is better is debatable, hence the
RFC designation. Patches in the series address these issues:
1) Should_continue_reclaim returns true too often.
Michal Hocko suggested removing the special casing for __GFP_RETRY_MAYFAIL
in should_continue_reclaim. This does indeed address the hugetlb
allocations, but may impact other users. Hillf Danton restructured
the code in such a way to preserve much of the original semantics. Hillf's
patch also addresses hugetlb allocation issues and is included here.
2) With 1) addressed, should_compact_retry returns true too often.
Mel Gorman suggested the removal of the compaction_zonelist_suitable() call.
This routine/call was introduced by Michal Hocko for a specific use case.
Therefore, removal would likely break that use case. While examining the
reasons for compaction_withdrawn() as in [2], it appears that there are
several places where we should be using MIN_COMPACT_COSTLY_PRIORITY instead
of MIN_COMPACT_PRIORITY for costly allocations. This patch makes those
changes which also causes more appropriate should_compact_retry behavior
for hugetlb allocations.
3) This is simply an optimization of the allocation code for hugetlb pool
pages. After first __GFP_RETRY_MAYFAIL allocation failure on a node,
it drops the __GFP_RETRY_MAYFAIL flag.
[1] http://lkml.kernel.org/r/d38a095e-dc39-7e82-bb76-2c9247929f07@oracle.com
[2] http://lkml.kernel.org/r/6377c199-2b9e-e30d-a068-c304d8a3f706@oracle.com
Hillf Danton (1):
mm, reclaim: make should_continue_reclaim perform dryrun detection
Mike Kravetz (2):
mm, compaction: use MIN_COMPACT_COSTLY_PRIORITY everywhere for costly
orders
hugetlbfs: don't retry when pool page allocations start to fail
mm/compaction.c | 18 +++++++---
mm/hugetlb.c | 87 +++++++++++++++++++++++++++++++++++++++++++------
mm/vmscan.c | 28 ++++++++--------
3 files changed, 105 insertions(+), 28 deletions(-)
--
2.20.1
next reply other threads:[~2019-07-24 17:52 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-24 17:50 Mike Kravetz [this message]
2019-07-24 17:50 ` [RFC PATCH 1/3] mm, reclaim: make should_continue_reclaim perform dryrun detection Mike Kravetz
2019-07-25 8:05 ` Mel Gorman
2019-07-26 8:12 ` Mel Gorman
2019-07-31 11:08 ` Vlastimil Babka
2019-07-31 12:25 ` Mel Gorman
2019-07-31 21:11 ` Mike Kravetz
2019-08-01 8:44 ` Vlastimil Babka
2019-07-24 17:50 ` [RFC PATCH 2/3] mm, compaction: use MIN_COMPACT_COSTLY_PRIORITY everywhere for costly orders Mike Kravetz
2019-07-25 8:06 ` Mel Gorman
2019-07-31 12:06 ` Vlastimil Babka
2019-07-31 20:30 ` Mike Kravetz
2019-08-01 13:01 ` Vlastimil Babka
2019-08-01 20:33 ` Mike Kravetz
2019-08-02 10:20 ` Vlastimil Babka
2019-08-02 12:05 ` Vlastimil Babka
2019-08-02 17:44 ` Mike Kravetz
2019-07-24 17:50 ` [RFC PATCH 3/3] hugetlbfs: don't retry when pool page allocations start to fail Mike Kravetz
2019-07-25 8:13 ` Mel Gorman
2019-07-25 17:15 ` Mike Kravetz
2019-07-25 22:43 ` Mel Gorman
2019-07-31 13:23 ` Vlastimil Babka
2019-07-31 21:13 ` Mike Kravetz
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=20190724175014.9935-1-mike.kravetz@oracle.com \
--to=mike.kravetz@oracle.com \
--cc=akpm@linux-foundation.org \
--cc=hannes@cmpxchg.org \
--cc=hdanton@sina.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@suse.de \
--cc=mhocko@kernel.org \
--cc=vbabka@suse.cz \
/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).