From: Christoph Lameter <cl@linux.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: npiggin@kernel.dk, Pekka Enberg <penberg@cs.helsinki.fi>,
David Rientjes <rientjes@google.com>,
linux-mm@kvack.org, Andi Kleen <andi@firstfloor.org>
Subject: Re: vmscan: Do not run shrinkers for zones other than ZONE_NORMAL
Date: Thu, 21 Oct 2010 15:03:32 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.00.1010211455100.30295@router.home> (raw)
In-Reply-To: <20101021124054.14b85e50.akpm@linux-foundation.org>
On Thu, 21 Oct 2010, Andrew Morton wrote:
> The patch doesn't patch direct reclaim, in do_try_to_free_pages(). How
> come?
Direct reclaim does not run node specific shrink_slab. Direct reclaim does
a general pass after the individual zones have been shrunk.
> OK, maybe this. Suppose we have a machine with 800M lowmem and 200M
> highmem. And suppose the lowmem region is stuffed full of clean
> icache/dcache. A __GFP_HIGHMEM allocation should put pressure on
> lowmem to get some of those pages back. What we don't want to do is to
> keep on reclaiming the highmem zone and allocating pages from there,
> because the machine would effectively end up with only 200M available
> for pagecache.
Shrinker reclaim is not zone specific. It either occurs on a node or on
the system as a whole. A failure of HIGHMEM allocation in the direct
reclaim path will result in shrinkers being called with NO_NUMA_NODE and
therefore global reclaim will take place everywhere.
Per node reclaim occurs from kswapd and covers all zones of that node.
> Please convince us that your patch doesn't screw up zone balancing?
There are no slab allocations in HIGHMEM or MOVABLE. Nothing to balance
there.
That reminds me: We also have counters on how many slabs exist in a given
zone these days. We could check for zero there and just not run the
shrinkers if zero. We could also use those counters to guide shrink_slab
in a better way.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2010-10-21 20:03 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-21 17:59 Christoph Lameter
2010-10-21 18:00 ` shrinkers: Add node to indicate where to target shrinking Christoph Lameter
2010-10-21 18:12 ` Andi Kleen
2010-10-21 20:57 ` David Rientjes
2010-10-21 21:07 ` Christoph Lameter
2010-10-22 13:27 ` Andi Kleen
2010-10-21 23:58 ` Nick Piggin
2010-10-22 12:12 ` Andi Kleen
2010-10-22 15:55 ` Christoph Hellwig
2010-10-22 16:32 ` Christoph Lameter
2010-10-24 1:42 ` Nick Piggin
2010-10-25 0:57 ` KOSAKI Motohiro
2010-10-25 14:59 ` Christoph Lameter
2010-11-09 4:03 ` Nick Piggin
2010-10-22 16:46 ` Andi Kleen
2010-10-24 1:31 ` Nick Piggin
2010-11-14 2:26 ` Michel Lespinasse
2010-11-14 7:10 ` KOSAKI Motohiro
2010-11-14 11:05 ` Michel Lespinasse
2010-11-15 0:29 ` KOSAKI Motohiro
2010-10-21 18:13 ` vmscan: Do not run shrinkers for zones other than ZONE_NORMAL Andi Kleen
2010-10-21 18:22 ` Christoph Lameter
2010-10-21 18:27 ` Christoph Lameter
2010-10-21 18:33 ` Andi Kleen
2010-10-21 20:48 ` David Rientjes
2010-10-21 20:54 ` Christoph Lameter
2010-10-21 19:40 ` Andrew Morton
2010-10-21 20:03 ` Christoph Lameter [this message]
2010-10-21 20:14 ` Andrew Morton
2010-10-21 20:28 ` Christoph Lameter
2010-10-21 20:36 ` Andrew Morton
2010-10-21 20:49 ` Christoph Lameter
2010-10-21 20:59 ` Andrew Morton
2010-10-21 21:13 ` Christoph Lameter
2010-10-21 21:21 ` Andrew Morton
2010-10-21 23:04 ` Christoph Lameter
2010-10-21 23:56 ` Nick Piggin
2010-10-22 1:37 ` KOSAKI Motohiro
2010-10-22 14:06 ` Christoph Lameter
2010-10-24 1:37 ` Nick Piggin
2010-10-25 1:22 ` KOSAKI Motohiro
2010-10-25 15:07 ` Christoph Lameter
2010-10-26 2:52 ` KOSAKI Motohiro
2010-10-26 12:42 ` KOSAKI Motohiro
2010-10-26 13:10 ` Christoph Lameter
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=alpine.DEB.2.00.1010211455100.30295@router.home \
--to=cl@linux.com \
--cc=akpm@linux-foundation.org \
--cc=andi@firstfloor.org \
--cc=linux-mm@kvack.org \
--cc=npiggin@kernel.dk \
--cc=penberg@cs.helsinki.fi \
--cc=rientjes@google.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