linux-kernel - Re: [PATCH 03/10] smp,cpumask: introduce on_each_cpu_cond

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Message-ID: <CALCETrUipqat-78++E8fL7d2=77Cbj72jCTZMO=yNF8nX9HhCA@mail.gmail.com>
Date:   Sat, 28 Jul 2018 19:57:24 -0700
From:   Andy Lutomirski <luto@...nel.org>
To:     Rik van Riel <riel@...riel.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        kernel-team <kernel-team@...com>,
        Peter Zijlstra <peterz@...radead.org>,
        Andrew Lutomirski <luto@...nel.org>, X86 ML <x86@...nel.org>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Ingo Molnar <mingo@...nel.org>, Mike Galbraith <efault@....de>,
        Dave Hansen <dave.hansen@...el.com>, will.daecon@....com,
        Catalin Marinas <catalin.marinas@....com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>
Subject: Re: [PATCH 03/10] smp,cpumask: introduce on_each_cpu_cond_mask

On Sat, Jul 28, 2018 at 2:53 PM, Rik van Riel <riel@...riel.com> wrote:
> Introduce a variant of on_each_cpu_cond that iterates only over the
> CPUs in a cpumask, in order to avoid making callbacks for every single
> CPU in the system when we only need to test a subset.

Nice.

Although, if you want to be really fancy, you could optimize this (or
add a variant) that does the callback on the local CPU in parallel
with the remote ones.  That would give a small boost to TLB flushes.