Re: [PATCH 6/7] wipe_page_reference return SWAP_AGAIN if VM pressulreis low and lock contention is detected.

From: Rik van Riel
Date: Sun Dec 06 2009 - 16:02:00 EST


On 12/04/2009 03:45 AM, KOSAKI Motohiro wrote:
From 3fb2a585729a37e205c5ea42ac6c48d4a6c0a29c Mon Sep 17 00:00:00 2001
From: KOSAKI Motohiro<kosaki.motohiro@xxxxxxxxxxxxxx>
Date: Fri, 4 Dec 2009 12:54:37 +0900
Subject: [PATCH 6/7] wipe_page_reference return SWAP_AGAIN if VM pressulre is low and lock contention is detected.

Larry Woodman reported AIM7 makes serious ptelock and anon_vma_lock
contention on current VM. because SplitLRU VM (since 2.6.28) remove
calc_reclaim_mapped() test, then shrink_active_list() always call
page_referenced() against mapped page although VM pressure is low.
Lightweight VM pressure is very common situation and it easily makes
ptelock contention with page fault. then, anon_vma_lock is holding
long time and it makes another lock contention. then, fork/exit
throughput decrease a lot.

It looks good to me. Larry, does this patch series resolve
your issue?

Acked-by: Rik van Riel <riel@xxxxxxxxxx>

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