From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <41C411BD.6090901@yahoo.com.au> Date: Sat, 18 Dec 2004 22:17:17 +1100 From: Nick Piggin MIME-Version: 1.0 Subject: Re: [PATCH 4/10] alternate 4-level page tables patches References: <41C3D453.4040208@yahoo.com.au> <41C3D479.40708@yahoo.com.au> <41C3D48F.8080006@yahoo.com.au> <41C3D4AE.7010502@yahoo.com.au> <41C3D4C8.1000508@yahoo.com.au> <41C3F2D6.6060107@yahoo.com.au> <20041218095050.GC338@wotan.suse.de> <41C40125.3060405@yahoo.com.au> <20041218110608.GJ771@holomorphy.com> In-Reply-To: <20041218110608.GJ771@holomorphy.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: William Lee Irwin III Cc: Andi Kleen , Linux Memory Management , Hugh Dickins , Linus Torvalds , Andrew Morton List-ID: William Lee Irwin III wrote: > On Sat, Dec 18, 2004 at 09:06:29PM +1100, Nick Piggin wrote: > >>Yes I thought about that a bit too. >>Note that this (4/10) patch should give perfect garbage collection too >>(modulo bugs). The difference is in where the overheads lie. I suspect >>refcounting may be too much overhead (at least, SMP overhead); especially >>in light of Christoph's results. > > > If this were so, then clear_page_tables() during process destruction > would be unnecessary. detach_vmas_to_be_unmapped() makes additional > work for such schemes, but even improvements are still rather helpful. > If what were so? > > On Sat, Dec 18, 2004 at 09:06:29PM +1100, Nick Piggin wrote: > >>Although I think it would enable you to do page table reclaim when >>reclaiming mapped, file backed pages quite easily... but I'm not sure if >>that is enough to offset the slowdowns. > > > That would be a far more appropriate response to high multiprogramming > levels than what is now done. > On a select few workloads, yes. -- 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: aart@kvack.org