From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx199.postini.com [74.125.245.199]) by kanga.kvack.org (Postfix) with SMTP id 2E0FF8D0001 for ; Fri, 11 May 2012 12:54:41 -0400 (EDT) Received: by wefh52 with SMTP id h52so806499wef.14 for ; Fri, 11 May 2012 09:54:39 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <4FACD00D.4060003@kernel.org> <4FACD573.4060103@kernel.org> From: Linus Torvalds Date: Fri, 11 May 2012 09:54:18 -0700 Message-ID: Subject: Re: [PATCH] mm: raise MemFree by reverting percpu_pagelist_fraction to 0 Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Sasha Levin Cc: Minchan Kim , Hugh Dickins , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Fri, May 11, 2012 at 9:35 AM, Sasha Levin wrote: > > Once it's on, we reserve 1/x of the pages for the pagelists. I'm not > sure why 8 was selected in the first place, but I guess it made sense > that you don't want to reserve 15%+ of your memory for the pagelists. Why not just accept any number, but turn small numbers into the minimum? And if it's a per-cpu, then the minimum had better depend on number of CPU's anyway. 15% of memory on a single-cpu already sounds insanely high, but if you have several cpu's, it's going to be just totally crazy. So a minimum of 8 already sounds broken. Exposing that minimum in a way that makes it impossible to reset it sounds just insane. Linus -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org