linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: mingo@kernel.org, tglx@linutronix.de,
	linux-kernel@vger.kernel.org, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
	paulmck@kernel.org, frederic@kernel.org,
	tsbogend@alpha.franken.de, axboe@kernel.dk, rjw@rjwysocki.net,
	daniel.lezcano@linaro.org, dchickles@marvell.com,
	davem@davemloft.net, kuba@kernel.org, daniel.thompson@linaro.org,
	gerald.schaefer@de.ibm.com
Subject: Re: [PATCH 6/6] smp: Cleanup smp_call_function*()
Date: Thu, 18 Jun 2020 18:25:49 +0200	[thread overview]
Message-ID: <20200618162549.GM576905@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200618065107.GA4406@infradead.org>

On Wed, Jun 17, 2020 at 11:51:07PM -0700, Christoph Hellwig wrote:
> Much better.  Although if we touch all the callers we might as well
> pass the csd as the argument to the callback, as with that we can
> pretty trivially remove the private data field later.

My plan was to introduce a new function and type and convert
smp_call_function_async() callers over to that. The csd as it exists is
useful for the regular smp_call_function*() API.

> Btw, it seems the callers that don't have the CSD embedded into the
> containing structure seems to be of these two kinds:
> 
>  - reimplementing on_each_cpumask (mostly because they can be called
>    from irq context)

These are fairly special purpose constructs; and they come at the cost
of extra per-cpu storage and they have the limitiation that they must
wait for completion of the first before they can be used again.

>  - reimplenenting smp_call_function_single because they want
>    to sleep instead of busy wait

These are atrocious pieces of crap (the x86/msr ones), the reason it was
done is because virt :/

  reply	other threads:[~2020-06-18 16:26 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-15 12:56 [PATCH 0/6] sched: TTWU, IPI, and assorted stuff Peter Zijlstra
2020-06-15 12:56 ` [PATCH 1/6] sched: Fix ttwu_queue_cond() Peter Zijlstra
2020-06-15 13:34   ` Peter Zijlstra
2020-06-15 16:45     ` Paul E. McKenney
2020-06-15 22:58       ` Paul E. McKenney
2020-06-22  9:11   ` Mel Gorman
2020-06-22  9:41     ` Peter Zijlstra
2020-06-15 12:56 ` [PATCH 2/6] sched: Verify some SMP assumptions Peter Zijlstra
2020-06-15 12:56 ` [PATCH 3/6] sched: s/WF_ON_RQ/WQ_ON_CPU/ Peter Zijlstra
2020-06-22  9:13   ` Mel Gorman
2020-06-15 12:56 ` [PATCH 4/6] smp, irq_work: Continue smp_call_function*() and irq_work*() integration Peter Zijlstra
2020-06-15 12:56 ` [PATCH 5/6] irq_work: Cleanup Peter Zijlstra
2020-06-16 15:16   ` Petr Mladek
2020-06-15 12:57 ` [PATCH 6/6] smp: Cleanup smp_call_function*() Peter Zijlstra
2020-06-15 14:34   ` Jens Axboe
2020-06-15 16:04   ` Daniel Thompson
2020-06-17  8:23   ` Christoph Hellwig
2020-06-17  9:00     ` Peter Zijlstra
2020-06-17 11:04     ` Peter Zijlstra
2020-06-18  6:51       ` Christoph Hellwig
2020-06-18 16:25         ` Peter Zijlstra [this message]
2020-06-15 16:23 ` [PATCH 0/6] sched: TTWU, IPI, and assorted stuff Paul E. McKenney
2020-06-15 16:40   ` Peter Zijlstra
2020-06-15 17:21     ` Paul E. McKenney
2020-06-15 19:11       ` Peter Zijlstra
2020-06-15 19:55         ` Paul E. McKenney
2020-06-16 16:31           ` Paul E. McKenney
2020-06-16 17:04         ` Peter Zijlstra
2020-06-16 17:17           ` Peter Zijlstra
2020-06-16 17:53             ` Paul E. McKenney
2020-06-19 13:44             ` Peter Zijlstra
2020-06-19 17:20               ` Paul E. McKenney
2020-06-19 17:48                 ` Paul E. McKenney
2020-06-19 18:11                   ` Peter Zijlstra
2020-06-19 18:46                     ` Paul E. McKenney
2020-06-20 18:46               ` Paul E. McKenney
2020-06-16 17:51           ` Paul E. McKenney

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200618162549.GM576905@hirez.programming.kicks-ass.net \
    --to=peterz@infradead.org \
    --cc=axboe@kernel.dk \
    --cc=bsegall@google.com \
    --cc=daniel.lezcano@linaro.org \
    --cc=daniel.thompson@linaro.org \
    --cc=davem@davemloft.net \
    --cc=dchickles@marvell.com \
    --cc=dietmar.eggemann@arm.com \
    --cc=frederic@kernel.org \
    --cc=gerald.schaefer@de.ibm.com \
    --cc=hch@infradead.org \
    --cc=juri.lelli@redhat.com \
    --cc=kuba@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mgorman@suse.de \
    --cc=mingo@kernel.org \
    --cc=paulmck@kernel.org \
    --cc=rjw@rjwysocki.net \
    --cc=rostedt@goodmis.org \
    --cc=tglx@linutronix.de \
    --cc=tsbogend@alpha.franken.de \
    --cc=vincent.guittot@linaro.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).