linux-kernel - Re: [PATCH 3/4] reuse unused swap entry if necessary

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Message-ID: <20090530064041.GF24073@balbir.in.ibm.com>
Date:	Sat, 30 May 2009 14:40:41 +0800
From:	Balbir Singh <balbir@...ux.vnet.ibm.com>
To:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
Cc:	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"nishimura@....nes.nec.co.jp" <nishimura@....nes.nec.co.jp>,
	"hugh.dickins@...cali.co.uk" <hugh.dickins@...cali.co.uk>,
	"hannes@...xchg.org" <hannes@...xchg.org>,
	"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>
Subject: Re: [PATCH 3/4] reuse unused swap entry if necessary

* KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com> [2009-05-28 14:20:47]:

> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
> 
> Now, we can know a swap entry is just used as SwapCache via swap_map,
> without looking up swap cache.
> 
> Then, we have a chance to reuse swap-cache-only swap entries in
> get_swap_pages().
> 
> This patch tries to free swap-cache-only swap entries if swap is
> not enough.
> Note: We hit following path when swap_cluster code cannot find
> a free cluster. Then, vm_swap_full() is not only condition to allow
> the kernel to reclaim unused swap.
> 
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>

Looks good, except the now changed behaviour where swap will get
distributed between clusters. Having the vm_swap_full() is a good
optimization for swap allocation performance though. I'd say lets wait
to see the results of testing


Acked-by: Balbir Singh <balbir@...ux.vnet.ibm.com>
 

-- 
	Balbir
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