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Mercier" Cc: Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton , android-mm@google.com, Minchan Kim , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: memcg: Don't periodically flush stats when memcg is disabled Message-ID: <20240126210642.GK1567330@cmpxchg.org> References: <20240126203353.1163059-1-tjmercier@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240126203353.1163059-1-tjmercier@google.com> On Fri, Jan 26, 2024 at 08:33:52PM +0000, T.J. Mercier wrote: > The root memcg is onlined even when memcg is disabled. When it's onlined > a 2 second periodic stat flush is started, but no stat flushing is > required when memcg is disabled because there can be no child memcgs. > Most calls to flush memcg stats are avoided when memcg is disabled as a > result of the mem_cgroup_disabled check [1] added in [2], but the > periodic flushing started in mem_cgroup_css_online is not. Skip it. > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/mm/memcontrol.c?h=v6.8-rc1#n753 > [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7d7ef0a4686abe43cd76a141b340a348f45ecdf2 > > Fixes: aa48e47e3906 ("memcg: infrastructure to flush memcg stats") > Reported-by: Minchan Kim > Signed-off-by: T.J. Mercier With what Shakeel pointed out resolved: Acked-by: Johannes Weiner