From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f200.google.com (mail-pf0-f200.google.com [209.85.192.200]) by kanga.kvack.org (Postfix) with ESMTP id 0F7EA6B0069 for ; Tue, 24 Jan 2017 23:25:17 -0500 (EST) Received: by mail-pf0-f200.google.com with SMTP id c73so261487960pfb.7 for ; Tue, 24 Jan 2017 20:25:17 -0800 (PST) Received: from mail-pf0-x241.google.com (mail-pf0-x241.google.com. [2607:f8b0:400e:c00::241]) by mx.google.com with ESMTPS id i88si22083832pfk.178.2017.01.24.20.25.16 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 24 Jan 2017 20:25:16 -0800 (PST) Received: by mail-pf0-x241.google.com with SMTP id e4so13399693pfg.0 for ; Tue, 24 Jan 2017 20:25:16 -0800 (PST) Date: Wed, 25 Jan 2017 13:25:30 +0900 From: Sergey Senozhatsky Subject: Re: [PATCH v7 11/12] zsmalloc: page migration support Message-ID: <20170125042530.GD2234@jagdpanzerIV.localdomain> References: <20170119024421.GA9367@bbox> <0a184bbf-0612-5f71-df68-c37500fa1eda@samsung.com> <20170119062158.GB9367@bbox> <20170123052244.GC11763@bbox> <20170123053056.GB2327@jagdpanzerIV.localdomain> <20170123054034.GA12327@bbox> <7488422b-98d1-1198-70d5-47c1e2bac721@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7488422b-98d1-1198-70d5-47c1e2bac721@samsung.com> Sender: owner-linux-mm@kvack.org List-ID: To: Chulmin Kim Cc: Minchan Kim , Andrew Morton , linux-mm@kvack.org, Dan Streetman , Seth Jennings , Sergey Senozhatsky , Sergey Senozhatsky On (01/24/17 23:06), Chulmin Kim wrote: [..] > > > > Yeb, Thanks. > > > > > > > > Perhaps, did you tried flush page before the writing? > > > > I think arm64 have no d-cache alising problem but worth to try it. > > > > Who knows :) > > > > > > I thought that flush_dcache_page() is only for cases when we write > > > to page (store that makes pages dirty), isn't it? > > > > I think we need both because to see recent stores done by the user. > > I'm not sure it should be done by block device driver rather than > > page cache. Anyway, brd added it so worth to try it, I thought. :) Cc Dan, Seth (https://marc.info/?l=linux-mm&m=148514896820940) > Thanks for the suggestion! > It might be helpful > though proving it is not easy as the problem appears rarely. > > Have you thought about > zram swap or zswap dealing with self modifying code pages (ex. JIT)? > (arm64 may have i-cache aliasing problem) > > If it is problematic, > especiallly zswap (without flush_dcache_page in zswap_frontswap_load()) may > provide the corrupted data > and even swap out (compressing) may see the corrupted data sooner or later, > i guess. hm, interesting. there is a report of zswap_frontswap_load() failing to decompress the page: https://marc.info/?l=linux-mm&m=148468457306971 -ss -- 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