From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f179.google.com (mail-ig0-f179.google.com [209.85.213.179]) by kanga.kvack.org (Postfix) with ESMTP id 95DE06B0032 for ; Tue, 24 Feb 2015 17:12:30 -0500 (EST) Received: by mail-ig0-f179.google.com with SMTP id l13so1044708iga.0 for ; Tue, 24 Feb 2015 14:12:30 -0800 (PST) Received: from mail-ie0-x233.google.com (mail-ie0-x233.google.com. [2607:f8b0:4001:c03::233]) by mx.google.com with ESMTPS id v5si10080774igb.35.2015.02.24.14.12.28 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 24 Feb 2015 14:12:28 -0800 (PST) Received: by iecrd18 with SMTP id rd18so36111124iec.8 for ; Tue, 24 Feb 2015 14:12:28 -0800 (PST) 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 Message-ID: Subject: Re: [PATCH] mm: readahead: get back a sensible upper limit From: Linus Torvalds Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: 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 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, 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