From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754134AbaLWC0P (ORCPT ); Mon, 22 Dec 2014 21:26:15 -0500 Received: from mail-oi0-f45.google.com ([209.85.218.45]:54991 "EHLO mail-oi0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751241AbaLWC0N (ORCPT ); Mon, 22 Dec 2014 21:26:13 -0500 MIME-Version: 1.0 In-Reply-To: <20141220022557.GA19822@blaptop> References: <1418993719-14291-1-git-send-email-opensource.ganesh@gmail.com> <20141219143244.1e5fabad8b6733204486f5bc@linux-foundation.org> <20141219233937.GA11975@blaptop> <20141219154548.3aa4cc02b3322f926aa4c1d6@linux-foundation.org> <20141219235852.GB11975@blaptop> <20141219160648.5cea8a6b0c764caa6100a585@linux-foundation.org> <20141220001043.GC11975@blaptop> <20141219161756.bcf7421acb4bc7a286c1afa3@linux-foundation.org> <20141220002303.GD11975@blaptop> <20141220022557.GA19822@blaptop> Date: Tue, 23 Dec 2014 10:26:12 +0800 Message-ID: Subject: Re: [PATCH v2] mm/zsmalloc: add statistics support From: Ganesh Mahendran To: Minchan Kim Cc: Andrew Morton , Nitin Gupta , Linux-MM , linux-kernel Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Minchan 2014-12-20 10:25 GMT+08:00 Minchan Kim : > Hey Ganesh, > > On Sat, Dec 20, 2014 at 09:43:34AM +0800, Ganesh Mahendran wrote: >> 2014-12-20 8:23 GMT+08:00 Minchan Kim : >> > On Fri, Dec 19, 2014 at 04:17:56PM -0800, Andrew Morton wrote: >> >> On Sat, 20 Dec 2014 09:10:43 +0900 Minchan Kim wrote: >> >> >> >> > > It involves rehashing a lengthy argument with Greg. >> >> > >> >> > Okay. Then, Ganesh, >> >> > please add warn message about duplicaed name possibility althoug >> >> > it's unlikely as it is. >> >> >> >> Oh, getting EEXIST is easy with this patch. Just create and destroy a >> >> pool 2^32 times and the counter wraps ;) It's hardly a serious issue >> >> for a debugging patch. >> > >> > I meant that I wanted to change from index to name passed from caller like this >> > >> > zram: >> > zs_create_pool(GFP_NOIO | __GFP_HIGHMEM, zram->disk->first_minor); >> > >> > So, duplication should be rare. :) >> >> We still can not know whether the name is duplicated if we do not >> change the debugfs API. >> The API does not return the errno to us. >> >> How about just zsmalloc decides the name of the pool-id, like pool-x. >> When the pool-id reaches >> 0xffff.ffff, we print warn message about duplicated name, and stop >> creating the debugfs entry >> for the user. > > The idea is from the developer point of view to implement thing easy > but my point is we should take care of user(ie, admin) rather than > developer(ie, we). Yes. I got it. > > For user, /sys/kernel/debug/zsmalloc/zram0 would be more > straightforward and even it doesn't need zram to export > /sys/block/zram0/pool-id. BTW, If we add a new argument in zs_create_pool(). It seems we also need to add argument in zs_zpool_create(). So, zpool/zswap/zbud will be modified to support the new API. Is that acceptable? Thanks. > > Thanks. > >> >> Thanks.