From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751882AbdAYNKP (ORCPT ); Wed, 25 Jan 2017 08:10:15 -0500 Received: from mx2.suse.de ([195.135.220.15]:50991 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751535AbdAYNKN (ORCPT ); Wed, 25 Jan 2017 08:10:13 -0500 Date: Wed, 25 Jan 2017 14:10:07 +0100 From: Michal Hocko To: Alexei Starovoitov Cc: Andrew Morton , Vlastimil Babka , David Rientjes , Mel Gorman , Johannes Weiner , Al Viro , linux-mm@kvack.org, LKML , Alexei Starovoitov , Anatoly Stepanov , Andreas Dilger , Andreas Dilger , Anton Vorontsov , Ben Skeggs , Boris Ostrovsky , Colin Cross , Dan Williams , David Sterba , Eric Dumazet , Eric Dumazet , Hariprasad S , Heiko Carstens , Herbert Xu , Ilya Dryomov , Kees Cook , Kent Overstreet , Martin Schwidefsky , "Michael S. Tsirkin" , Mike Snitzer , Oleg Drokin , Paolo Bonzini , "Rafael J. Wysocki" , Santosh Raspatur , Tariq Toukan , "Theodore Ts'o" , Tom Herbert , Tony Luck , "Yan, Zheng" , Yishai Hadas , Daniel Borkmann Subject: Re: [PATCH 0/6 v3] kvmalloc Message-ID: <20170125131006.GQ32377@dhcp22.suse.cz> References: <20170112153717.28943-1-mhocko@kernel.org> <20170124151752.GO6867@dhcp22.suse.cz> <20170124191716.GA23114@ast-mbp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170124191716.GA23114@ast-mbp.thefacebook.com> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 24-01-17 11:17:21, Alexei Starovoitov wrote: > On Tue, Jan 24, 2017 at 04:17:52PM +0100, Michal Hocko wrote: > > On Thu 12-01-17 16:37:11, Michal Hocko wrote: > > > Hi, > > > this has been previously posted as a single patch [1] but later on more > > > built on top. It turned out that there are users who would like to have > > > __GFP_REPEAT semantic. This is currently implemented for costly >64B > > > requests. Doing the same for smaller requests would require to redefine > > > __GFP_REPEAT semantic in the page allocator which is out of scope of > > > this series. > > > > > > There are many open coded kmalloc with vmalloc fallback instances in > > > the tree. Most of them are not careful enough or simply do not care > > > about the underlying semantic of the kmalloc/page allocator which means > > > that a) some vmalloc fallbacks are basically unreachable because the > > > kmalloc part will keep retrying until it succeeds b) the page allocator > > > can invoke a really disruptive steps like the OOM killer to move forward > > > which doesn't sound appropriate when we consider that the vmalloc > > > fallback is available. > > > > > > As it can be seen implementing kvmalloc requires quite an intimate > > > knowledge if the page allocator and the memory reclaim internals which > > > strongly suggests that a helper should be implemented in the memory > > > subsystem proper. > > > > > > Most callers I could find have been converted to use the helper instead. > > > This is patch 5. There are some more relying on __GFP_REPEAT in the > > > networking stack which I have converted as well but considering we do > > > not have a support for __GFP_REPEAT for requests smaller than 64kB I > > > have marked it RFC. > > > > Are there any more comments? I would really appreciate to hear from > > networking folks before I resubmit the series. > > while this patchset was baking the bpf side switched to use bpf_map_area_alloc() > which fixes the issue with missing __GFP_NORETRY that we had to fix quickly. > See commit d407bd25a204 ("bpf: don't trigger OOM killer under pressure with map alloc") > it covers all kmalloc/vmalloc pairs instead of just one place as in this set. > So please rebase and switch bpf_map_area_alloc() to use kvmalloc(). OK, will do. Thanks for the heads up. -- Michal Hocko SUSE Labs From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f71.google.com (mail-wm0-f71.google.com [74.125.82.71]) by kanga.kvack.org (Postfix) with ESMTP id E7E4F6B0038 for ; Wed, 25 Jan 2017 08:10:12 -0500 (EST) Received: by mail-wm0-f71.google.com with SMTP id d140so37985371wmd.4 for ; Wed, 25 Jan 2017 05:10:12 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id g109si26844971wrd.9.2017.01.25.05.10.11 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 25 Jan 2017 05:10:11 -0800 (PST) Date: Wed, 25 Jan 2017 14:10:07 +0100 From: Michal Hocko Subject: Re: [PATCH 0/6 v3] kvmalloc Message-ID: <20170125131006.GQ32377@dhcp22.suse.cz> References: <20170112153717.28943-1-mhocko@kernel.org> <20170124151752.GO6867@dhcp22.suse.cz> <20170124191716.GA23114@ast-mbp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170124191716.GA23114@ast-mbp.thefacebook.com> Sender: owner-linux-mm@kvack.org List-ID: To: Alexei Starovoitov Cc: Andrew Morton , Vlastimil Babka , David Rientjes , Mel Gorman , Johannes Weiner , Al Viro , linux-mm@kvack.org, LKML , Alexei Starovoitov , Anatoly Stepanov , Andreas Dilger , Andreas Dilger , Anton Vorontsov , Ben Skeggs , Boris Ostrovsky , Colin Cross , Dan Williams , David Sterba , Eric Dumazet , Eric Dumazet , Hariprasad S , Heiko Carstens , Herbert Xu , Ilya Dryomov , Kees Cook , Kent Overstreet , Martin Schwidefsky , "Michael S. Tsirkin" , Mike Snitzer , Oleg Drokin , Paolo Bonzini , "Rafael J. Wysocki" , Santosh Raspatur , Tariq Toukan , Theodore Ts'o , Tom Herbert , Tony Luck , "Yan, Zheng" , Yishai Hadas , Daniel Borkmann On Tue 24-01-17 11:17:21, Alexei Starovoitov wrote: > On Tue, Jan 24, 2017 at 04:17:52PM +0100, Michal Hocko wrote: > > On Thu 12-01-17 16:37:11, Michal Hocko wrote: > > > Hi, > > > this has been previously posted as a single patch [1] but later on more > > > built on top. It turned out that there are users who would like to have > > > __GFP_REPEAT semantic. This is currently implemented for costly >64B > > > requests. Doing the same for smaller requests would require to redefine > > > __GFP_REPEAT semantic in the page allocator which is out of scope of > > > this series. > > > > > > There are many open coded kmalloc with vmalloc fallback instances in > > > the tree. Most of them are not careful enough or simply do not care > > > about the underlying semantic of the kmalloc/page allocator which means > > > that a) some vmalloc fallbacks are basically unreachable because the > > > kmalloc part will keep retrying until it succeeds b) the page allocator > > > can invoke a really disruptive steps like the OOM killer to move forward > > > which doesn't sound appropriate when we consider that the vmalloc > > > fallback is available. > > > > > > As it can be seen implementing kvmalloc requires quite an intimate > > > knowledge if the page allocator and the memory reclaim internals which > > > strongly suggests that a helper should be implemented in the memory > > > subsystem proper. > > > > > > Most callers I could find have been converted to use the helper instead. > > > This is patch 5. There are some more relying on __GFP_REPEAT in the > > > networking stack which I have converted as well but considering we do > > > not have a support for __GFP_REPEAT for requests smaller than 64kB I > > > have marked it RFC. > > > > Are there any more comments? I would really appreciate to hear from > > networking folks before I resubmit the series. > > while this patchset was baking the bpf side switched to use bpf_map_area_alloc() > which fixes the issue with missing __GFP_NORETRY that we had to fix quickly. > See commit d407bd25a204 ("bpf: don't trigger OOM killer under pressure with map alloc") > it covers all kmalloc/vmalloc pairs instead of just one place as in this set. > So please rebase and switch bpf_map_area_alloc() to use kvmalloc(). OK, will do. Thanks for the heads up. -- Michal Hocko SUSE Labs -- 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/ . 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