Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755782Ab3FKTCW (ORCPT ); Tue, 11 Jun 2013 15:02:22 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:48092 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753475Ab3FKTCV (ORCPT ); Tue, 11 Jun 2013 15:02:21 -0400 Message-ID: <51B77433.4080305@oracle.com> Date: Tue, 11 Jun 2013 15:02:11 -0400 From: Sasha Levin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130510 Thunderbird/17.0.6 MIME-Version: 1.0 To: Eric Dumazet CC: Christoph Lameter , Pekka Enberg , "linux-mm@kvack.org" , Andrew Morton , LKML Subject: Re: [PATCH] slab: prevent warnings when allocating with __GFP_NOWARN References: <1370891880-2644-1-git-send-email-sasha.levin@oracle.com> <51B62F6B.8040308@oracle.com> <0000013f3075f90d-735942a8-b4b8-413f-a09e-57d1de0c4974-000000@email.amazonses.com> <51B67553.6020205@oracle.com> <51B72323.8040207@oracle.com> <0000013f33cdc631-eadb07d1-ef08-4e2c-a218-1997eb86cde9-000000@email.amazonses.com> <51B73F38.6040802@kernel.org> <0000013f33d58923-88767793-2187-476d-b500-dba3c22607aa-000000@email.amazonses.com> <51B745F9.9080609@oracle.com> <1370967193.3252.47.camel@edumazet-glaptop> <51B74E28.4070906@oracle.com> <1370968655.3252.49.camel@edumazet-glaptop> In-Reply-To: <1370968655.3252.49.camel@edumazet-glaptop> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 958 Lines: 29 On 06/11/2013 12:37 PM, Eric Dumazet wrote: > On Tue, 2013-06-11 at 12:19 -0400, Sasha Levin wrote: > >> It might be, but you need CAP_SYS_RESOURCE to go into the dangerous >> zone (>pipe_max_size). >> >> So if root (or someone with that cap) wants to go there, as Rusty says: >> "Root asked, we do." > > Yes and no : adding a test to select vmalloc()/vfree() instead of > kmalloc()/kfree() will slow down regular users asking 32 pages in their > pipe. > > If there is no _sensible_ use for large pipes even for root, please do > not bloat the code just because we can. The code to allow root to grow pipes is quite ancient. Either we drop it or we fix it, leaving it broken as it is is silly. Thanks, Sasha -- 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/