From mboxrd@z Thu Jan 1 00:00:00 1970 In-reply-to: (message from Linus Torvalds on Wed, 23 Jan 2008 11:35:21 -0800 (PST)) Subject: Re: [PATCH -v8 3/4] Enable the MS_ASYNC functionality in sys_msync() References: <12010440803930-git-send-email-salikhmetov@gmail.com> <1201044083504-git-send-email-salikhmetov@gmail.com> <1201110066.6341.65.camel@lappy> Message-Id: From: Miklos Szeredi Date: Wed, 23 Jan 2008 20:55:34 +0100 Sender: owner-linux-mm@kvack.org Return-Path: To: torvalds@linux-foundation.org Cc: a.p.zijlstra@chello.nl, 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, akpm@linux-foundation.org, protasnb@gmail.com, miklos@szeredi.hu, r.e.wolff@bitwizard.nl, hidave.darkstar@gmail.com, hch@infradead.org List-ID: > > > > It would need some addition piece to not call msync_interval() for > > MS_SYNC, and remove the balance_dirty_pages_ratelimited_nr() stuff. > > > > But yeah, this pte walker is much better. > > Actually, I think this patch is much better. > > Anyway, it's better because: > - it actually honors the range > - it uses the same code for MS_ASYNC and MS_SYNC > - it just avoids doing the "wait for" for MS_ASYNC. > > However, it's totally untested, of course. What did you expect? Clean code > _and_ testing? > > [ Side note: it is quite possible that we should not do the > SYNC_FILE_RANGE_WAIT_BEFORE on MS_ASYNC, and just skip over pages that > are busily under writeback already. MS_ASYNC is not supposed to wait, so SYNC_FILE_RANGE_WAIT_BEFORE probably should not be used in that case. What would be perfect, is if we had a sync mode, that on encountering a page currently under writeback, would just do a page_mkclean() on it, so we still receive a page fault next time one of the mappings is dirtied, so the times can be updated. Would there be any difficulties with that? 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