From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751642AbbEASuJ (ORCPT ); Fri, 1 May 2015 14:50:09 -0400 Received: from mga03.intel.com ([134.134.136.65]:54549 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751078AbbEASuG convert rfc822-to-8bit (ORCPT ); Fri, 1 May 2015 14:50:06 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,351,1427785200"; d="scan'208";a="719201999" From: "Drokin, Oleg" To: Julia Lawall CC: "Simmons, James A." , "devel@driverdev.osuosl.org" , Greg Kroah-Hartman , "kernel-janitors@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "HPDD-discuss@lists.01.org" Subject: Re: [HPDD-discuss] [PATCH 2/11] Staging: lustre: fld: Use kzalloc and kfree Thread-Topic: [HPDD-discuss] [PATCH 2/11] Staging: lustre: fld: Use kzalloc and kfree Thread-Index: AQHQhDcX/Si4kRb33kqKwqEINQFc2Z1n7BAA Date: Fri, 1 May 2015 18:49:39 +0000 Message-ID: References: <1430495482-933-1-git-send-email-Julia.Lawall@lip6.fr> <1430495482-933-11-git-send-email-Julia.Lawall@lip6.fr> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.252.199.128] Content-Type: text/plain; charset="us-ascii" Content-ID: <41A845BD49B93D40A8E6FD9DA8ADC125@intel.com> Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello! On May 1, 2015, at 1:48 PM, Julia Lawall wrote: >>> From: Julia Lawall >>> >>> Replace OBD_ALLOC, OBD_ALLOC_WAIT, OBD_ALLOC_PTR, and OBD_ALLOC_PTR_WAIT by >>> kalloc/kcalloc, and OBD_FREE and OBD_FREE_PTR by kfree. >> >> Nak: James Simmons >> >> A simple replace will not work. The OBD_ALLOC and OBD_FREE functions allocate memory >> anywhere from one page to 4MB in size. You can't use kmalloc for the 4MB allocations. >> Currently lustre uses a 4 page water mark to determine if we allocate using vmalloc. Even >> using kmalloc for 4 pages has shown high failure rates on some systems. It gets even more >> messy with 64K page systems like ppc64 boxes. Now I'm not suggesting to port the larger >> allocations to vmalloc either since issues have been founded with using vmalloc. For example >> when using large stripe count files the MDS rpc generated crosses the 4 page line and vmalloc >> is used. Using vmalloc caused a global spinlock to be taken which causes meta data operations >> to serialized on the MDS servers. > > It's not the LARGE functions that do the switching? For example OBD_ALLOC > ends up at __OBD_MALLOC_VERBOSE, which as far as I can see calls kmalloc > (with __GFP_ZERO, and hance the use of kzalloc). This is true. We have OBD_ALLOC that is straight kmalloc and then we have OBD_ALLOC_LARGE that depends on allocation size whenever it's kmalloc or vmalloc. Similarly we have OBD_FREE and OBD_FREE_LARGE (This one could be converted straight into kvfree). I think the patches look fine. Bye, Oleg