From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 28 Feb 2008 17:17:33 -0600 From: Jack Steiner Subject: Re: [PATCH] mmu notifiers #v7 Message-ID: <20080228231732.GA21604@sgi.com> References: <20080219135851.GI7128@v2.random> <20080219231157.GC18912@wotan.suse.de> <20080220010941.GR7128@v2.random> <20080220103942.GU7128@v2.random> <20080221045430.GC15215@wotan.suse.de> <20080221144023.GC9427@v2.random> <20080221161028.GA14220@sgi.com> <20080227192610.GF28483@v2.random> <20080228215257.GJ8091@v2.random> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080228215257.GJ8091@v2.random> Sender: owner-linux-mm@kvack.org Return-Path: To: Andrea Arcangeli Cc: Christoph Lameter , Nick Piggin , akpm@linux-foundation.org, Robin Holt , Avi Kivity , Izik Eidus , kvm-devel@lists.sourceforge.net, Peter Zijlstra , general@lists.openfabrics.org, Steve Wise , Roland Dreier , Kanoj Sarcar , linux-kernel@vger.kernel.org, linux-mm@kvack.org, daniel.blueman@quadrics.com List-ID: > > The release should be called much earlier to allow the driver to release > > all resources in one go. This way each vma must be processed individually. > > For our gobs of memory this method may create a scaling problem on exit(). > > Good point, it has to be called earlier for GRU, but it's not a > performance issue. GRU doesn't pin the pages so it should make the > global invalidate in ->release _before_ unmap_vmas. Linux can't fault > in the ptes anymore because mm_users is zero so there's no need of a > ->release_begin/end, the _begin is enough. > I disagree. The location of the callout IS a performance issue. In simple comparisons of the 2 patches (Christoph's vs. Andrea's), Andrea's has a 7X increase in the number of TLB purges being issued to the GRU. TLB flushing is slow and can impact the performance of of tasks using the GRU. --- jack -- 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