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[70.30.145.63]) by smtp.gmail.com with ESMTPSA id 73-20020a370c4c000000b007423ccd892csm397038qkm.47.2023.03.02.13.01.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Mar 2023 13:01:09 -0800 (PST) Date: Thu, 2 Mar 2023 16:01:07 -0500 From: Peter Xu To: Marcelo Tosatti Cc: Christoph Lameter , Aaron Tomlin , Frederic Weisbecker , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2 10/11] mm/vmstat: switch vmstat shepherd to flush per-CPU counters remotely Message-ID: References: <20230209150150.380060673@redhat.com> <20230209153204.901518530@redhat.com> MIME-Version: 1.0 In-Reply-To: <20230209153204.901518530@redhat.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: A1FC8C003E X-Rspam-User: X-Stat-Signature: iw7kqz4winbk4dp7r65mmefw3cfchjna X-HE-Tag: 1677790872-569815 X-HE-Meta: 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 UpMJ6npW zZ2+Ge8myg96/KSvCXukyJdYo2iern5BU1cFdR1LI+jfe4sYYUPe2672PT4tF+oCRfKoypRcV/UwUrkGTIe/046nIwHsk5zakchMHU3mwPawx5PXyV7nTlYBpuYbjMFbAHnRzW7jjyD3YUWtqF/MB2Kh6hlYdVErBu0KdARmKZN6LWdG65s6zs+PCIBRJwB5AxhXaCLXA/8dpGYCoKIKVX7Zriiy/VBKGDGuBlvUo+Nt5x4BG++DmO2AG/gd+P8nSiNv33p34sDc1C2YQNjgQuwAfVLrA+rp/0fp7uqI2vJ1X62GqTGWWAbG93hthOwoKIangsTHAimDO7Fqe9TNoP/m++KVgGw3BeLAn+4TzCTpkNbO4mJHi/+GxhTDxiEZk/jyMkP9fiA9VHsQ= 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 Thu, Feb 09, 2023 at 12:02:00PM -0300, Marcelo Tosatti wrote: > +#ifdef CONFIG_HAVE_CMPXCHG_LOCAL > +/* Flush counters remotely if CPU uses cmpxchg to update its per-CPU counters */ > +static void vmstat_shepherd(struct work_struct *w) > +{ > + int cpu; > + > + cpus_read_lock(); > + for_each_online_cpu(cpu) { > + cpu_vm_stats_fold(cpu); Nitpick: IIUC this line is the only change with CONFIG_HAVE_CMPXCHG_LOCAL to replace the queuing. Would it be cleaner to move the ifdef into vmstat_shepherd, then, and keep the common logic? > + cond_resched(); > + } > + cpus_read_unlock(); > + > + schedule_delayed_work(&shepherd, > + round_jiffies_relative(sysctl_stat_interval)); > +} > +#else > static void vmstat_shepherd(struct work_struct *w) > { > int cpu; > @@ -2026,6 +2043,7 @@ static void vmstat_shepherd(struct work_ > schedule_delayed_work(&shepherd, > round_jiffies_relative(sysctl_stat_interval)); > } > +#endif > > static void __init start_shepherd_timer(void) > { > > > -- Peter Xu