From: Andrew Morton <akpm@linux-foundation.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>,
linux-kernel@vger.kernel.org, Oleg Nesterov <oleg@redhat.com>
Subject: Re: [PATCH] signal: reorder struct sighand_struct
Date: Thu, 23 May 2019 19:11:15 -0700 [thread overview]
Message-ID: <20190523191115.66a4d57dc0ae991415fa131e@linux-foundation.org> (raw)
In-Reply-To: <20190504233302.GT29835@dhcp22.suse.cz>
On Sat, 4 May 2019 19:33:02 -0400 Michal Hocko <mhocko@kernel.org> wrote:
> CCing Oleg.
>
> On Fri 03-05-19 22:28:00, Alexey Dobriyan wrote:
> [...]
> > add/remove: 0/0 grow/shrink: 8/68 up/down: 49/-1147 (-1098)
> [...]
> > --- a/include/linux/sched/signal.h
> > +++ b/include/linux/sched/signal.h
> > @@ -15,10 +15,10 @@
> > */
> >
> > struct sighand_struct {
> > - refcount_t count;
> > - struct k_sigaction action[_NSIG];
> > spinlock_t siglock;
> > + refcount_t count;
> > wait_queue_head_t signalfd_wqh;
> > + struct k_sigaction action[_NSIG];
> > };
>
> Is it possible that this would cause false sharing of the cache line
> that would have performance implications now?
Doesn't seem likely. Possible .count vs .siglock, but .count only gets
altered by fork/exec-style code, so it's pretty low bandwidth.
prev parent reply other threads:[~2019-05-24 2:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-03 19:28 Alexey Dobriyan
2019-05-04 23:33 ` Michal Hocko
2019-05-24 2:11 ` Andrew Morton [this message]
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