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[70.30.145.63]) by smtp.gmail.com with ESMTPSA id n190-20020a37bdc7000000b0071a291f0a4asm453257qkf.27.2023.03.02.13.30.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Mar 2023 13:30:42 -0800 (PST) Date: Thu, 2 Mar 2023 16:30:41 -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: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Rspamd-Queue-Id: 8BCE34000E X-Stat-Signature: zx8ckii4p8nwiwwh1trohwt6i4fawhq3 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1677792645-933675 X-HE-Meta: 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 2koqcnee NKuORwyBqS8W6Vy//T9lam6L2vYXpTIium7a3VH6ZuJo+Lkho3JPBk8St2Bn+oGOKLtuejfXW38Sx9dh4OoAHzT0mD2/u7/obxpDkoNLi0XyPAViGmovclugtnav2VX/ALs5zhUed5xTQ5IzZmpVieNY0OX2H5j1UaYD9hnKyLig3DSgPiRgiRJZeIZpX6vOXIE+DJgHlxWfwPh+SA0Ae5a8S4SOYDBdOvlv67SxGdHyKr8N8Ggka3R2QvzxIE7kXssakihVJdJp6E0zEN2kMpS9dLmnNpa7c3+l6ogo8bzogVsD1PCsSPvilc+L7xhiBNfzgwqoRov/mzVZFvABrKjGDGWmJuPUR5CQDtHe8VWd2P0QTKpSmJvfymLmOHVw0lEszmoduvsqNbvmwYrWPj4byI3P2b/z+ufb0cmmJ+zYDkUlnKyEiB+2dTg== 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, Mar 02, 2023 at 06:16:42PM -0300, Marcelo Tosatti wrote: > On Thu, Mar 02, 2023 at 04:01:07PM -0500, Peter Xu wrote: > > 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? > > https://lore.kernel.org/lkml/20221223144150.GA79369@lothringen/ :-) [...] > So it seems the current separation is quite readable > (unless you have a suggestion). No, feel free to ignore any of my nitpicks when you don't think proper. :) Keeping it is fine to me. -- Peter Xu