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Sat, 14 Aug 2021 01:01:10 -0700 (PDT) MIME-Version: 1.0 References: <1628855870-5070-1-git-send-email-wang.yong12@zte.com.cn> In-Reply-To: From: yong w Date: Sat, 14 Aug 2021 16:00:59 +0800 Message-ID: Subject: Re: [PATCH v1] mm: Add configuration to control whether vmpressure notifier is enabled To: Chris Down Cc: tj@kernel.org, corbet@lwn.net, akpm@linux-foundation.org, mhocko@kernel.org, vdavydov.dev@gmail.com, tglx@linutronix.de, peterz@infradead.org, Shakeel Butt , guro@fb.com, alexs@kernel.org, richard.weiyang@gmail.com, sh_def@163.com, sfr@canb.auug.org.au, wang.yong12@zte.com.cn, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, yang.yang29@zte.com.cn Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=gmail.com header.s=20161025 header.b=nPEBvsm7; spf=pass (imf12.hostedemail.com: domain of yongwpur@gmail.com designates 209.85.208.52 as permitted sender) smtp.mailfrom=yongwpur@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: E9FF810003E7 X-Stat-Signature: pu4eyojhprr1kgh4xah4g5u4nemw5xs8 X-HE-Tag: 1628928071-809954 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: Chris Down =E4=BA=8E2021=E5=B9=B48=E6=9C=8813=E6=97= =A5=E5=91=A8=E4=BA=94 =E4=B8=8B=E5=8D=888:36=E5=86=99=E9=81=93=EF=BC=9A > > yongw.pur@gmail.com writes: > >From: wangyong > >Inspired by PSI features, vmpressure inotifier function should also be > >configured to decide whether it is used, because it is an independent > >feature which notifies the user of memory pressure. > > > >Since the vmpressure interface is used in kernel common code, for > >users who do not use the vmpressure function, there will be > >additional overhead. > > Could you please demonstrate this additional overhead with profiles or > demonstrations of other real world effects? Thanks. Thanks for your reply. In terms of code, it will reduce the operation of some code. To demonstrate this additional overhead, It is planned to use lmbench and Christoph Lamenter=E2=80=99s pagefault tool (https://lkml.org/lkml/2006/8/= 29/294) for comparative testing. Thanks.