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[37.188.174.201]) by smtp.gmail.com with ESMTPSA id a3sm9652169wrp.91.2020.06.12.05.09.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Jun 2020 05:09:06 -0700 (PDT) Date: Fri, 12 Jun 2020 14:09:04 +0200 From: Michal Hocko To: Naresh Kamboju Cc: Chris Down , Yafang Shao , Anders Roxell , "Linux F2FS DEV, Mailing List" , linux-ext4 , linux-block , Andrew Morton , open list , Linux-Next Mailing List , linux-mm , Arnd Bergmann , Andreas Dilger , Jaegeuk Kim , Theodore Ts'o , Chao Yu , Hugh Dickins , Andrea Arcangeli , Matthew Wilcox , Chao Yu , lkft-triage@lists.linaro.org, Johannes Weiner , Roman Gushchin , Cgroups Subject: Re: mm: mkfs.ext4 invoked oom-killer on i386 - pagecache_get_page Message-ID: <20200612120904.GA8641@dhcp22.suse.cz> References: <20200528150310.GG27484@dhcp22.suse.cz> <20200528164121.GA839178@chrisdown.name> <20200529015644.GA84588@chrisdown.name> <20200529094910.GH4406@dhcp22.suse.cz> <20200611095514.GD20450@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Fri 12-06-20 15:13:22, Naresh Kamboju wrote: > On Thu, 11 Jun 2020 at 15:25, Michal Hocko wrote: > > > > On Fri 29-05-20 11:49:20, Michal Hocko wrote: > > > On Fri 29-05-20 02:56:44, Chris Down wrote: > > > > Yafang Shao writes: > > > Agreed. Even if e{low,min} might still have some rough edges I am > > > completely puzzled how we could end up oom if none of the protection > > > path triggers which the additional debugging should confirm. Maybe my > > > debugging patch is incomplete or used incorrectly (maybe it would be > > > esier to use printk rather than trace_printk?). > > > > It would be really great if we could move forward. While the fix (which > > has been dropped from mmotm) is not super urgent I would really like to > > understand how it could hit the observed behavior. Can we double check > > that the debugging patch really doesn't trigger (e.g. > > s@trace_printk@printk in the first step)? > > Please suggest to me the way to get more debug information > by providing kernel debug patches and extra kernel configs. > > I have applied your debug patch and tested on top on linux next 20200612 > but did not find any printk output while running mkfs -t ext4 /drive test case. Have you tried s@trace_printk@printk@ in the patch? AFAIK trace_printk doesn't dump anything into the printk ring buffer. You would have to look into trace ring buffer. -- Michal Hocko SUSE Labs