From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f181.google.com (mail-pd0-f181.google.com [209.85.192.181]) by kanga.kvack.org (Postfix) with ESMTP id 3EBC96B0032 for ; Thu, 4 Dec 2014 01:49:07 -0500 (EST) Received: by mail-pd0-f181.google.com with SMTP id v10so11621820pde.26 for ; Wed, 03 Dec 2014 22:49:06 -0800 (PST) Received: from lgeamrelo02.lge.com (lgeamrelo02.lge.com. [156.147.1.126]) by mx.google.com with ESMTP id zs6si9670477pac.109.2014.12.03.22.49.04 for ; Wed, 03 Dec 2014 22:49:05 -0800 (PST) Message-ID: <548003F1.2080004@lge.com> Date: Thu, 04 Dec 2014 15:49:21 +0900 From: =?UTF-8?B?IuuwleyKue2YuC/ssYXsnoTsl7Dqtazsm5AvU1cgUGxhdGZvcm0o7JewKQ==?= =?UTF-8?B?QU9U7YyAKHNldW5naG8xLnBhcmtAbGdlLmNvbSki?= MIME-Version: 1.0 Subject: Re: [RFC 0/6] zsmalloc support compaction References: <1417488587-28609-1-git-send-email-minchan@kernel.org> In-Reply-To: <1417488587-28609-1-git-send-email-minchan@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim , Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Nitin Gupta , Dan Streetman , Seth Jennings , Sergey Senozhatsky , Luigi Semenzato , Jerome Marchand , juno.choi@lge.com Hi, Minchan. I have a question. The problem mentioned can't be resolved with compaction? Is there any reason that zsmalloc pages can't be moved by compaction operation in direct reclaim? 2014-12-02 i??i ? 11:49i?? Minchan Kim i?'(e??) i?' e,?: > Recently, there was issue about zsmalloc fragmentation and > I got a report from Juno that new fork failed although there > are plenty of free pages in the system. > His investigation revealed zram is one of the culprit to make > heavy fragmentation so there was no more contiguous 16K page > for pgd to fork in the ARM. > > This patchset implement *basic* zsmalloc compaction support > and zram utilizes it so admin can do > "echo 1 > /sys/block/zram0/compact" > > Actually, ideal is that mm migrate code is aware of zram pages and > migrate them out automatically without admin's manual opeartion > when system is out of contiguous page. Howver, we need more thinking > before adding more hooks to migrate.c. Even though we implement it, > we need manual trigger mode, too so I hope we could enhance > zram migration stuff based on this primitive functions in future. > > I just tested it on only x86 so need more testing on other arches. > Additionally, I should have a number for zsmalloc regression > caused by indirect layering. Unfortunately, I don't have any > ARM test machine on my desk. I will get it soon and test it. > Anyway, before further work, I'd like to hear opinion. > > Pathset is based on v3.18-rc6-mmotm-2014-11-26-15-45. > > Thanks. > > Minchan Kim (6): > zsmalloc: expand size class to support sizeof(unsigned long) > zsmalloc: add indrection layer to decouple handle from object > zsmalloc: implement reverse mapping > zsmalloc: encode alloced mark in handle object > zsmalloc: support compaction > zram: support compaction > > drivers/block/zram/zram_drv.c | 24 ++ > drivers/block/zram/zram_drv.h | 1 + > include/linux/zsmalloc.h | 1 + > mm/zsmalloc.c | 596 +++++++++++++++++++++++++++++++++++++----- > 4 files changed, 552 insertions(+), 70 deletions(-) > -- 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