From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 10 Oct 2006 09:30:10 +0200 From: Nick Piggin Subject: Re: [patch] mm: bug in set_page_dirty_buffers Message-ID: <20061010073010.GC14557@wotan.suse.de> References: <20061010035851.GK15822@wotan.suse.de> <20061009211404.ad112128.akpm@osdl.org> <20061010042144.GM15822@wotan.suse.de> <20061009213806.b158ea82.akpm@osdl.org> <20061010044745.GA24600@wotan.suse.de> <20061009220127.c4721d2d.akpm@osdl.org> <20061010052248.GB24600@wotan.suse.de> <1160462936.27479.4.camel@taijtu> <20061010065927.GA14557@wotan.suse.de> <1160464263.27479.13.camel@taijtu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1160464263.27479.13.camel@taijtu> Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Zijlstra Cc: Andrew Morton , Linus Torvalds , Linux Memory Management List , Greg KH List-ID: On Tue, Oct 10, 2006 at 09:11:03AM +0200, Peter Zijlstra wrote: > On Tue, 2006-10-10 at 08:59 +0200, Nick Piggin wrote: > > > > What's your problem with zap_pte_range? > > well, not only zap_pte_range, also page_remove_rmap and > try_to_unmap_cluster etc.. Basically all those who fiddle with the page > without holding the page lock. Fiddle with the page -- as in setting it dirty? Because there is a huge amount of other stuff that fiddles with the page without taking the lock ;) > Because with concurrent pagecache, there is no tree lock anymore to > protect/pin the whole mapping, I need to go pin individual pages. > Perhaps having an inner page bit-spinlock (PG_pin) isn't a bad thing, > I'd just raised the issue to see if it would be doable/a-good-thing to > try and merge these two. It does seem attractive, but at the moment I can't see how it would be done. One of the main problems is that truncate / invalidate need to hold the page locked while traversing the rmaps (which require i_mmap_lock, ptl locks, etc). There are other things too, like the swapcache, which uses PG_locked as an outer lock. -- 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