From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Subject: Re: [PATCH v3] mm/page_owner: use kvmalloc instead of kmalloc Date: Wed, 31 Oct 2018 12:41:07 +0100 Message-ID: <20181031114107.GM32673@dhcp22.suse.cz> References: <1540790176-32339-1-git-send-email-miles.chen@mediatek.com> <20181029080708.GA32673@dhcp22.suse.cz> <20181029081706.GC32673@dhcp22.suse.cz> <1540862950.12374.40.camel@mtkswgap22> <20181030060601.GR32673@dhcp22.suse.cz> <1540882551.23278.12.camel@mtkswgap22> <20181030081537.GV32673@dhcp22.suse.cz> <1540975637.10275.10.camel@mtkswgap22> <20181031101501.GL32673@dhcp22.suse.cz> <1540981182.16084.1.camel@mtkswgap22> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1540981182.16084.1.camel@mtkswgap22> Sender: linux-kernel-owner@vger.kernel.org To: Miles Chen Cc: Andrew Morton , Joe Perches , Matthew Wilcox , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, wsd_upstream@mediatek.com List-Id: linux-mediatek@lists.infradead.org On Wed 31-10-18 18:19:42, Miles Chen wrote: > On Wed, 2018-10-31 at 11:15 +0100, Michal Hocko wrote: > > On Wed 31-10-18 16:47:17, Miles Chen wrote: > > > On Tue, 2018-10-30 at 09:15 +0100, Michal Hocko wrote: > > > > On Tue 30-10-18 14:55:51, Miles Chen wrote: > > > > [...] > > > > > It's a real problem when using page_owner. > > > > > I found this issue recently: I'm not able to read page_owner information > > > > > during a overnight test. (error: read failed: Out of memory). I replace > > > > > kmalloc() with vmalloc() and it worked well. > > > > > > > > Is this with trimming the allocation to a single page and doing shorter > > > > than requested reads? > > > > > > > > > I printed out the allocate count on my device the request count is <= > > > 4096. So I tested this scenario by trimming the count to from 4096 to > > > 1024 bytes and it works fine. > > > > > > count = count > 1024? 1024: count; > > > > > > It tested it on both 32bit and 64bit kernel. > > > > Are you saying that you see OOMs for 4k size? > > > yes, because kmalloc only use normal memor, not highmem + normal memory > I think that's why vmalloc() works. Can I see an OOM report please? I am especially interested that 1k doesn't cause the problem because there shouldn't be that much of a difference between the two. Larger allocations could be a result of memory fragmentation but 1k vs. 4k to make a difference really seems unexpected. -- Michal Hocko SUSE Labs