From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 21 Aug 2005 20:32:37 -0700 (PDT) From: Christoph Lameter Subject: Re: [PATCH] Use deltas to replace atomic inc In-Reply-To: <20050820005843.21ba4d9b.akpm@osdl.org> Message-ID: References: <20050817151723.48c948c7.akpm@osdl.org> <20050817174359.0efc7a6a.akpm@osdl.org> <20050818212939.7dca44c3.akpm@osdl.org> <20050820005843.21ba4d9b.akpm@osdl.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: torvalds@osdl.org, hugh@veritas.com, nickpiggin@yahoo.com.au, linux-mm@kvack.org List-ID: On Sat, 20 Aug 2005, Andrew Morton wrote: > Christoph Lameter wrote: > > > > @@ -508,6 +508,16 @@ static int unuse_mm(struct mm_struct *mm > > { > > struct vm_area_struct *vma; > > > > + /* > > + * Ensure that existing deltas are charged to the current mm since > > + * we will charge the next batch manually to the target mm > > + */ > > + if (current->mm && mm_counter_updates_pending(current)) { > > Is there a race window right here? Why? current is tied to a thread. The thing that bothers me more is that schedule() can be called both by handle_mm_fault as well as during unuse_mm. We may need some flag PF_NO_COUNTER_UPDATES or so there to insure that schedule() does not add deltas to the current->mm. -- 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