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b=dBMu/PYg97a2NKvVHbrjBWh2mNwSXmrIiiuWc7RkO7KcIjMUlkrCOvUdL1tbtpl6P U/WI/rrgKK3NpKFPkwLG95EgA9//Em21Sb6D6CpSWT8JPPepjf60rcSdyiuCTu5A54 9dFL7m1gAeuYyjSGGUaOGwjOG9CqnH5G+xf9wXC0= Date: Thu, 31 Oct 2024 16:06:04 -0700 From: Andrew Morton To: Kinsey Ho Cc: Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Pasha Tatashin , David Rientjes , willy@infradead.org, Vlastimil Babka , David Hildenbrand , Joel Granados , Kaiyang Zhao , Sourav Panda , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH mm-unstable v1 0/2] Track pages allocated for struct Message-Id: <20241031160604.bcd5740390f05a01409b64f3@linux-foundation.org> In-Reply-To: <20241031224551.1736113-1-kinseyho@google.com> References: <20241031224551.1736113-1-kinseyho@google.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: B50021C000F X-Stat-Signature: kefhzhsm1awzfk8du3xhhk6tyfwpudmc X-Rspam-User: X-HE-Tag: 1730469432-605079 X-HE-Meta: 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 GHw/pj81 mSIr86D0LczICh2nHdK48DaNvMH2bpjmN1BIKoidVzl34JuDmGOz5xz0FRjTAKV03WZkJmRQ7knlQk0gP34aABPUce7zX4fZx64GrwaaXw2JEAra6Ee3SD7iI+JZOzwjEZ+WVIHh5xbmMvoc+bWZqZ05w94TI67CK61qVD1Kygd4ZS/oi6lGwzyUzOfNbtNDfynNbfpB/l4g3dnQFF9FZ+cIw0zCZnHP8zJIh5RfdJeutvI1QwEtVGKx2KOGRlM8ItK4OWa8Q1TvniZmmK+dI3yGSTg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: hm. On Thu, 31 Oct 2024 22:45:49 +0000 Kinsey Ho wrote: > We noticed high overhead for pages allocated for struct swap_cgroup in > our fleet. This is scanty. Please describe the problem further. > This patchset adds the number of pages allocated for struct > swap_cgroup to vmstat. This can be a useful metric for identifying > unneeded overhead on systems which configure swap. Possibly dumb question: can we switch swap_cgroup_prepare to kmalloc() (or kmem-cache_alloc()) and use slab's accounting to satisfy this requirement? > Before adding the new stat, Patch 1 introduces a generic system-wide > counting interface. I don't really understand this one and would like to hear much more about the motivation. And: "the existing use case" is OK with a global counter, but what about future use cases? And: what are the future use cases? Thanks.