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charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: nmwifkmdkpywg3msb8s5qdshp5em6sdr X-Rspamd-Queue-Id: 0268A18001C X-HE-Tag: 1674822818-41720 X-HE-Meta: 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 bZF/DnJw SgwyOUUleTxO/gu/k39XyaMCRxi35wtSxV0RIVJE6UZfCMuYhAZlRYkcs7jai+aNdfbgU73b6U0razmkgYTu3lao2iLhJIASNr6jiL29aldONNQYmlJDPnCfQ1OmYzuXmMu64wImm1X+Qz8modBj/VLoPpSJi24dTfGnLHZkCR114khYrIj9sALLsSQ/uWNSj7j5uOXUKyWxf+tcqM1rV2dVbl8YeBnyL/70AJUoD/Ig9d1J13jjTto+27/Qxcm3Dhw/ZFgH7AhXra/CyM7Eov6Q5QNZ9uos4OxX4 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: On Fri 27-01-23 20:43:20, Hyeonggon Yoo wrote: > On Wed, Jan 25, 2023 at 10:51:05AM +0100, Michal Hocko wrote: > > On Thu 26-01-23 00:41:15, Hyeonggon Yoo wrote: > > [...] > > > > Do you happen to have any perf data collected during those runs? I > > > > would be interested in the memcg side of things. Maybe we can do > > > > something better there. > > > > > > Yes, below is performance data I've collected. > > > > > > 6.1.8-debug-preempt-dirty > > > ========================= > > > Overhead Command Shared Object Symbol > > > + 9.14% hackbench [kernel.vmlinux] [k] check_preemption_disabled > > > > Thanks! Could you just add callers that are showing in the profile for > > this call please? > > - 14.56% 9.14% hackbench [kernel.vmlinux] [k] check_preemption_disabled > - 6.37% check_preemption_disabled > + 3.48% mod_objcg_state > + 1.10% obj_cgroup_charge > 1.02% refill_obj_stock > 0.67% memcg_slab_post_alloc_hook > 0.58% mod_objcg_state > > According to perf, many memcg functions call this function > and that's because __this_cpu_xxxx checks if preemption is disabled. OK, I see. Thanks! I was thinking whether we can optimize for that bu IIUC __this_cpu* is already an optimized form. mod_objcg_state is already called with local_lock so raw_cpu* could be used in that path but I guess this is not really worth just to optimize for a debug compile option to benefit. -- Michal Hocko SUSE Labs