Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753232AbbBXWMa (ORCPT ); Tue, 24 Feb 2015 17:12:30 -0500 Received: from mail-ig0-f180.google.com ([209.85.213.180]:61038 "EHLO mail-ig0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752326AbbBXWM3 (ORCPT ); Tue, 24 Feb 2015 17:12:29 -0500 MIME-Version: 1.0 In-Reply-To: <20150224220843.GL19014@t510.redhat.com> References: <9cc2b63100622f5fd17fa5e4adc59233a2b41877.1424779443.git.aquini@redhat.com> <20150224220843.GL19014@t510.redhat.com> Date: Tue, 24 Feb 2015 14:12:28 -0800 X-Google-Sender-Auth: 57edJbR6Fe4C5l-pDzD-c3Dfejk Message-ID: Subject: Re: [PATCH] mm: readahead: get back a sensible upper limit From: Linus Torvalds To: Rafael Aquini Cc: linux-mm , Andrew Morton , Johannes Weiner , Rik van Riel , David Rientjes , Linux Kernel Mailing List , loberman@redhat.com, Larry Woodman , Raghavendra K T Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1169 Lines: 29 On Tue, Feb 24, 2015 at 2:08 PM, Rafael Aquini wrote: > > Would you consider bringing it back, but instead of node memory state, > utilizing global memory state instead? Maybe. At least it would be saner than picking random values that make absolutely no sense. > People filing bugs complaining their applications that memory map files > are getting hurt by it. Show them. And as mentioned, last time this came up (and it has come up before), it wasn't actually a real load, but some benchmark that just did the prefetch, and then people were upset because their benchmark numbers changed. Which quite frankly doesn't make me care. The benchmark could equally well just be changed to do prefetching in saner chunks instead. So I really want to see real numbers from real loads, not some nebulous "people noticed and complain" that doesn't even specify what they did. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/