linux-kernel - Re: [PATCH 0/5] Improve sequential read throughput v4r8

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 1 Jul 2014 21:58:17 +0100
From:	Mel Gorman <mgorman@...e.de>
To:	Johannes Weiner <hannes@...xchg.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	Linux-MM <linux-mm@...ck.org>,
	Linux-FSDevel <linux-fsdevel@...r.kernel.org>
Subject: Re: [PATCH 0/5] Improve sequential read throughput v4r8

On Tue, Jul 01, 2014 at 07:39:15PM +0100, Mel Gorman wrote:
> The fair zone policy itself is partially working against the lowmem
> reserve idea. The point of the lowmem reserve was to preserve the lower
> zones when an upper zone can be used and the fair zone policy breaks
> that. The fair zone policy ignores that and it was never reconciled. The
> dirty page distribution does a different interleaving again and was never
> reconciled with the fair zone policy or lowmem reserves. kswapd itself was
> not using the classzone_idx it actually woken for although in this case
> it may not matter. The end result is that the model is fairly inconsistent
> which makes comparison against it a difficult exercise at best. About all
> that was left was that from a performance perspective that the fair zone
> allocation policy is not doing the right thing for streaming workloads.
> 

The inevitable feedback will be to reconcile those differences so I'm
redid the series and queued it for testing. Patch list currently looks
like

mm: pagemap: Avoid unnecessary overhead when tracepoints are deactivated
mm: Rearrange zone fields into read-only, page alloc, statistics and page reclaim lines
mm: page_alloc: Add ALLOC_DIRTY for dirty page distribution
mm: page_alloc: Only apply the fair zone allocation policy if it's eligible
mm: page_alloc: Only apply either the fair zone or dirty page distribution policy, not both
mm: page_alloc: Reduce cost of the fair zone allocation policy
mm: page_alloc: Reconcile lowmem reserves with fair zone allocation policy
mm: vmscan: Fix oddities with classzone and zone balancing
mm: vmscan: Reconcile balance gap lowmem reclaim with fair zone allocation policy
mm: vmscan: Remove classzone considerations from kswapd decisions

About 13 hours to test for ext3 on the small machine, 3 days for the larger
machine. The test could be accelerated by either reducing the iterations or
the memory size of the machine but that would distort the results too badly.

-- 
Mel Gorman
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/