From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id 8FB436B004F for ; Thu, 13 Aug 2009 13:45:31 -0400 (EDT) Date: Thu, 13 Aug 2009 18:45:18 +0100 (BST) From: Hugh Dickins Subject: Re: [PATCH] swap: send callback when swap slot is freed In-Reply-To: <4A837AAF.4050103@vflare.org> Message-ID: References: <200908122007.43522.ngupta@vflare.org> <4A837AAF.4050103@vflare.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Nitin Gupta Cc: Matthew Wilcox , Ingo Molnar , Peter Zijlstra , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Thu, 13 Aug 2009, Nitin Gupta wrote: > On 08/13/2009 04:18 AM, Hugh Dickins wrote: > > > But fundamentally, though I can see how this cutdown communication > > path is useful to compcache, I'd much rather deal with it by the more > > general discard route if we can. > > I tried this too -- make discard bio request as soon as a swap slot becomes > free (I can send details if you want). However, I could not get it to work. I'll send you an updated version of what I experimented with eight months ago: but changes in the swap_map count handling since then mean that it might need some subtle adjustments - I'll need to go over it carefully and retest before sending you. (But that won't be a waste of my time: I shall soon need to try that experiment again myself, and I do need to examine those intervening swap_map count changes more closely.) > Also, allocating bio to issue discard I/O request looks like a complete > artifact in compcache case. Yes, I do understand that feeling. Hugh -- 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: email@kvack.org