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[209.85.220.65]) by mx.google.com with SMTPS id z16sor2270538wmc.11.2019.01.29.10.05.18 for (Google Transport Security); Tue, 29 Jan 2019 10:05:19 -0800 (PST) Received-SPF: pass (google.com: domain of surenb@google.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=pTMYdsjV; spf=pass (google.com: domain of surenb@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=surenb@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Y+ap6Bq9i9Bosxjv/aC11VsPIK0N0Zh2bt/qMaK7RFo=; b=pTMYdsjVGlPjGB46EzZOJP2ZzDqCQrAqtMKteb4meGoxCxhdPbKwQR1sea+cC+6KTW G+seq4FJVEvK5CRhVUtH84btkAFM7Xc4jxG+SDLF8sUlDknTuC2WFvELFSNqQRh3hYCG CvcEgmI2ubiEKT3037EZFz8oCFJ9h2vrXZeY/DN5KatkMVTeIUt85CojWalyztZWPCu9 5UNFCramOZsutLuabzLGoYyV22vjYFlPJrv+sIbEz+foWtJ/T43QYM6ELa5elREGVVhI DNszJWv4OwXbAtfHWrgmqegPvT7xs193W6REmvUd1rwEKb5NxMrkXxmOSbFn7DV+Sf2Z wrqg== X-Google-Smtp-Source: ALg8bN7LYSdl+dRdBBbTvxW1GBHoyD6o/TBUVTnGWPtKZpAzgWSqhyM1ZtFKfRYRVtnOYo2pX0CGBDOWEMoPtBdoZiE= X-Received: by 2002:a7b:c04e:: with SMTP id u14mr20579255wmc.133.1548785118461; Tue, 29 Jan 2019 10:05:18 -0800 (PST) MIME-Version: 1.0 References: <20190124211518.244221-1-surenb@google.com> <20190124211518.244221-6-surenb@google.com> <20190129104431.GJ28467@hirez.programming.kicks-ass.net> In-Reply-To: <20190129104431.GJ28467@hirez.programming.kicks-ass.net> From: Suren Baghdasaryan Date: Tue, 29 Jan 2019 10:05:07 -0800 Message-ID: Subject: Re: [PATCH v3 5/5] psi: introduce psi monitor To: Peter Zijlstra Cc: Greg Kroah-Hartman , Tejun Heo , lizefan@huawei.com, Johannes Weiner , axboe@kernel.dk, dennis@kernel.org, Dennis Zhou , Ingo Molnar , Andrew Morton , Jonathan Corbet , cgroups@vger.kernel.org, linux-mm , linux-doc@vger.kernel.org, LKML , kernel-team@android.com Content-Type: text/plain; charset="UTF-8" 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: Thanks for review Peter! On Tue, Jan 29, 2019 at 2:44 AM Peter Zijlstra wrote: > > On Thu, Jan 24, 2019 at 01:15:18PM -0800, Suren Baghdasaryan wrote: > > static void psi_update_work(struct work_struct *work) > > { > > struct delayed_work *dwork; > > struct psi_group *group; > > + bool first_pass = true; > > + u64 next_update; > > + u32 change_mask; > > + int polling; > > bool nonidle; > > + u64 now; > > > > dwork = to_delayed_work(work); > > group = container_of(dwork, struct psi_group, clock_work); > > > > + now = sched_clock(); > > + > > + mutex_lock(&group->update_lock); > > actually acquiring a mutex can take a fairly long while; would it not > make more sense to take the @now timestanp _after_ it, instead of > before? Yes, that makes sense. As long as *now* is set before the *retry* label, otherwise the retry mechanism would get even more complicated to understand with floating *now* timestamp. Will move the assignment right after the mutex_lock() > -- > You received this message because you are subscribed to the Google Groups "kernel-team" group. > To unsubscribe from this group and stop receiving emails from it, send an email to kernel-team+unsubscribe@android.com. >