From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH 2.5.43-mm2] New shared page table patch References: <2458064740.1035069495@[10.10.2.3]> From: ebiederm@xmission.com (Eric W. Biederman) Date: 21 Oct 2002 08:55:24 -0600 In-Reply-To: <2458064740.1035069495@[10.10.2.3]> Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-linux-mm@kvack.org Return-Path: To: "Martin J. Bligh" Cc: Bill Davidsen , Dave McCracken , Andrew Morton , Linux Kernel , Linux Memory Management List-ID: "Martin J. Bligh" writes: > >> For reference, one of the tests was TPC-H. My code reduced the number of > >> allocated pte_chains from 5 million to 50 thousand. > > > > Don't tease, what did that do for performance? I see that someone has > > already posted a possible problem, and the code would pass for complex for > > most people, so is the gain worth the pain? > > In many cases, this will stop the box from falling over flat on it's > face due to ZONE_NORMAL exhaustion (from pte-chains), or even total > RAM exhaustion (from PTEs). Thus the performance gain is infinite ;-) So why has no one written a pte_chain reaper? It is perfectly sane to allocate a swap entry and move an entire pte_chain to the swap cache. Eric -- 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/