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b=dOagZkFG6Gc62lzuwMJRJJzkQV8CIhtugiv0P5+TKez/UD1tuO6p2NmR70OiI7REe oIwLe9BZEsjadElzy0En08MveOXBp87KOOZNDCr34MIH1QYm5JJlKY47tDwr9c1d59 6x9tTIR+KGXCCZv9QycksYXO2ZttX65vMCYpbk7gIISItTEm3akRDXTOjFcoz4Dazw F23lZVluxM1XDydRjaULvdxwZgPmOet7rn5KDgRcLzdqiGpIZKuUBNgRfm9C9fCqiQ TXXnGCRFjxm6iMUGnmz9nDrKR2SPblLVpNQ8usNl4/8FDOzYo7EQLOT50trJFIiDsY vaJzl3cuaTA4g== Date: Wed, 19 Mar 2025 09:10:12 -1000 From: Tejun Heo To: Yosry Ahmed Cc: Johannes Weiner , Greg Thelen , Michal =?iso-8859-1?Q?Koutn=FD?= , Andrew Morton , Eric Dumazet , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Eric Dumazet Subject: Re: [PATCH] cgroup/rstat: avoid disabling irqs for O(num_cpu) Message-ID: References: <20250319071330.898763-1-gthelen@google.com> <20250319180643.GC1876369@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Queue-Id: 3F9E4A0017 X-Rspamd-Server: rspam08 X-Stat-Signature: 7g3nofhfpu6pmqtdxcd7w4wyz47fhddr X-HE-Tag: 1742411415-83754 X-HE-Meta: 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 5uCujUy+ 7QOxUYayCltwHg/7ctLMjsL7hCza3N9U1FxCU5LxzevaNsMGEbGWdkwFnJl6NGrYpxZd9X3L8ihczQHIj5juop9wqT048++DJsvWHtR3TLJaS2HpE1nEMsjLw6t017/qS7QJ2itZPRPc8y/i2UbUtJBRsK3ZjAUYHDgtfo/sd9CBczJqUjLU8QKYrKy0Wmmr8RWEw4UTCrZ7fK7WcV7Szy7Nzxun0RuiimUD7tzE+LwGPrUjPGoukUIw/q5lh/Q4pByVR3plHtKJ+Jg4= 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: On Wed, Mar 19, 2025 at 06:35:02PM +0000, Yosry Ahmed wrote: > On Wed, Mar 19, 2025 at 02:06:43PM -0400, Johannes Weiner wrote: > > On Wed, Mar 19, 2025 at 05:16:02PM +0000, Yosry Ahmed wrote: > > > @@ -365,9 +352,8 @@ __bpf_kfunc void cgroup_rstat_flush(struct cgroup *cgrp) > > > void cgroup_rstat_flush_hold(struct cgroup *cgrp) > > > __acquires(&cgroup_rstat_lock) > > > { > > > - might_sleep(); > > > + cgroup_rstat_flush(cgrp); > > > __cgroup_rstat_lock(cgrp, -1); > > > - cgroup_rstat_flush_locked(cgrp); > > > } > > > > Might as well remove cgroup_rstat_flush_hold/release entirely? There > > are no external users, and the concept seems moot when the lock is > > dropped per default. cgroup_base_stat_cputime_show() can open-code the > > lock/unlock to stabilize the counts while reading. > > Yeah I missed the fact that the users are internal because the functions > are not static. I also don't see the point of keeping them. > > Tejun/Greg, should I send a patch on top of this one or do you prefer > sending a new version? Please send a patch on top. Thanks. -- tejun