From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 80A252F51; Mon, 27 Nov 2023 21:43:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="RERa00m1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A920C433C7; Mon, 27 Nov 2023 21:43:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1701121380; bh=CoO2w1Aaayjts+dtvAb8Eh6H5/dRtPDx1TPM+uYjYAI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=RERa00m1APTZ4nW8M04Rfr5i0iygE8BDQ0e6DmhSMgrHZ7Jw8YuA+xtP69/WxezsS rJMo7RPAVGmSaP6y2uf2uCKw0+eW38cOjgSScmhCD+QpioQ4N661eUERXRrVP0Lsvr wLF7BGf+jgv/d4EqPdkzSwHborOYqRliIGg2SYhE= Date: Mon, 27 Nov 2023 13:42:59 -0800 From: Andrew Morton To: Nhat Pham Cc: hannes@cmpxchg.org, cerasuolodomenico@gmail.com, yosryahmed@google.com, sjenning@redhat.com, ddstreet@ieee.org, vitaly.wool@konsulko.com, mhocko@kernel.org, roman.gushchin@linux.dev, shakeelb@google.com, muchun.song@linux.dev, chrisl@kernel.org, linux-mm@kvack.org, kernel-team@meta.com, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, shuah@kernel.org Subject: Re: [PATCH v6 2/6] memcontrol: allows mem_cgroup_iter() to check for onlineness Message-Id: <20231127134259.67b69ab47f4f88c9751e5222@linux-foundation.org> In-Reply-To: <20231127193703.1980089-3-nphamcs@gmail.com> References: <20231127193703.1980089-1-nphamcs@gmail.com> <20231127193703.1980089-3-nphamcs@gmail.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 27 Nov 2023 11:36:59 -0800 Nhat Pham wrote: > The new zswap writeback scheme requires an online-only memcg hierarchy > traversal. Add a new parameter to mem_cgroup_iter() to check for > onlineness before returning. I get a few build errors, perhaps because of patch timing issues... mm/shrinker_debug.c: In function 'shrinker_debugfs_count_show': mm/shrinker_debug.c:64:17: error: too few arguments to function 'mem_cgroup_iter' 64 | memcg = mem_cgroup_iter(NULL, NULL, NULL); | ^~~~~~~~~~~~~~~ In file included from mm/shrinker_debug.c:7: ./include/linux/memcontrol.h:833:20: note: declared here 833 | struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *, | ^~~~~~~~~~~~~~~ mm/shrinker_debug.c:89:27: error: too few arguments to function 'mem_cgroup_iter' 89 | } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL); | ^~~~~~~~~~~~~~~ ./include/linux/memcontrol.h:833:20: note: declared here 833 | struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *, | ^~~~~~~~~~~~~~~ mm/damon/sysfs-schemes.c: In function 'damon_sysfs_memcg_path_to_id': mm/damon/sysfs-schemes.c:1594:22: error: too few arguments to function 'mem_cgroup_iter' 1594 | for (memcg = mem_cgroup_iter(NULL, NULL, NULL); memcg; | ^~~~~~~~~~~~~~~ In file included from ./include/linux/damon.h:11, from mm/damon/sysfs-common.h:8, from mm/damon/sysfs-schemes.c:10: ./include/linux/memcontrol.h:833:20: note: declared here 833 | struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *, | ^~~~~~~~~~~~~~~ mm/damon/sysfs-schemes.c:1595:33: error: too few arguments to function 'mem_cgroup_iter' 1595 | memcg = mem_cgroup_iter(NULL, memcg, NULL)) { | ^~~~~~~~~~~~~~~ ./include/linux/memcontrol.h:833:20: note: declared here 833 | struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *, | ^~~~~~~~~~~~~~~ > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -832,7 +832,7 @@ static inline void mem_cgroup_put(struct mem_cgroup *memcg) > > struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *, > struct mem_cgroup *, > - struct mem_cgroup_reclaim_cookie *); > + struct mem_cgroup_reclaim_cookie *, bool online); How many callsites do we expect to utilize the new `online' argument? Few, I suspect. How about we fix the above and simplify the patch by adding a new mem_cgroup_iter_online() and make mem_cgroup_iter() a one-line wrapper which calls that and adds the online=false argument? I also saw this, didn't investigate. drivers/android/binder_alloc.c: In function 'binder_update_page_range': drivers/android/binder_alloc.c:237:34: error: too few arguments to function 'list_lru_del' 237 | on_lru = list_lru_del(&binder_alloc_lru, &page->lru);