From mboxrd@z Thu Jan 1 00:00:00 1970 In-reply-to: <1200429167.26045.45.camel@twins> (message from Peter Zijlstra on Tue, 15 Jan 2008 21:32:47 +0100) Subject: Re: [PATCH 0/2] Updating ctime and mtime for memory-mapped files [try #4] References: <12004129652397-git-send-email-salikhmetov@gmail.com> <1200429167.26045.45.camel@twins> Message-Id: From: Miklos Szeredi Date: Tue, 15 Jan 2008 21:40:47 +0100 Sender: owner-linux-mm@kvack.org Return-Path: To: a.p.zijlstra@chello.nl Cc: miklos@szeredi.hu, salikhmetov@gmail.com, linux-mm@kvack.org, jakob@unthought.net, linux-kernel@vger.kernel.org, valdis.kletnieks@vt.edu, riel@redhat.com, ksm@42.dk, staubach@redhat.com, jesper.juhl@gmail.com, torvalds@linux-foundation.org, akpm@linux-foundation.org, protasnb@gmail.com List-ID: > On Tue, 2008-01-15 at 21:27 +0100, Miklos Szeredi wrote: > > > 1. Introduction > > > > > > This is the fourth version of my solution for the bug #2645: > > > > > > http://bugzilla.kernel.org/show_bug.cgi?id=2645 > > > > > > Changes since the previous version: > > > > > > 1) the case of retouching an already-dirty page pointed out > > > by Miklos Szeredi has been addressed; > > > > I'm a bit sceptical, as we've also pointed out, that this is not > > possible without messing with the page tables. > > > > Did you try my test program on the patched kernel? > > > > I've refreshed the patch, where we left this issue last time. It > > should basically have equivalent functionality to your patch, and is a > > lot simpler. There might be performance issues with it, but it's a > > good starting point. > > It has the same problem as Anton's in that it won't get triggered again > for an already dirty mapped page. Yes, it's not better in this respect, than Anton's patch. And it might be worse performance-wise, since file_update_time() is sure to be slower, than set_bit(). According to Andrew, this may not actually matter in practice, but that would have to be benchmarked, I guess. Miklos -- 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