From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org,
tglx@linutronix.de
Subject: Re: [PATCH RT v2] crypto: limit more FPU-enabled sections
Date: Fri, 1 Dec 2017 14:32:56 +0100 [thread overview]
Message-ID: <20171201133256.GE1612@linutronix.de> (raw)
In-Reply-To: <20171201113235.6tmkwtov5cg2locv@hirez.programming.kicks-ass.net>
On 2017-12-01 12:32:35 [+0100], Peter Zijlstra wrote:
> On Fri, Dec 01, 2017 at 11:44:22AM +0100, Sebastian Andrzej Siewior wrote:
…
> > +static void camellia_fpu_sched_rt(struct crypt_priv *ctx)
> > +{
> > + bool fpu_enabled = ctx->fpu_enabled;
> > +
> > + if (!fpu_enabled || !tif_need_resched_now())
> > + return;
> > + camellia_fpu_end(fpu_enabled);
> > + kernel_fpu_end();
> > + /* schedule due to preemptible */
> > + kernel_fpu_begin();
> > +}
>
> There's a ton of duplication in there; you're not nearly lazy enough.
>
> Why can't we do something simple like kernel_fpu_resched() ?
>
> diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
> index f92a6593de1e..05321b98a55a 100644
> --- a/arch/x86/kernel/fpu/core.c
> +++ b/arch/x86/kernel/fpu/core.c
> @@ -130,6 +130,18 @@ void kernel_fpu_begin(void)
> }
> EXPORT_SYMBOL_GPL(kernel_fpu_begin);
>
> +void kernel_fpu_resched(void)
> +{
> + WARN_ON_FPU(!this_cpu_read(in_kernel_fpu));
> +
> + if (should_resched(PREEMPT_OFFSET)) {
> + kernel_fpu_end();
> + cond_resched();
> + kernel_fpu_begin();
I can do that but I would still keep it RT only to avoid the
kernel_fpu_begin/end to be invoked more often on !RT.
But why that cond_resched()? kernel_fpu_end() ends with preempt_enable()
and this one should do the trick.
> + }
> +}
> +EXPORT_SYMBOL_GPL(kernel_fpu_resched);
> +
> void kernel_fpu_end(void)
> {
> __kernel_fpu_end();
Sebastian
next prev parent reply other threads:[~2017-12-01 13:33 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-30 14:22 [PATCH RT] crypto: limit more FPU-enabled sections Sebastian Andrzej Siewior
2017-11-30 14:30 ` Sebastian Andrzej Siewior
2017-12-01 10:43 ` [PATCH RT] arm*: disable NEON in kernel mode Sebastian Andrzej Siewior
2017-12-01 13:45 ` Sebastian Andrzej Siewior
2017-12-01 14:18 ` Mark Rutland
2017-12-01 14:36 ` Sebastian Andrzej Siewior
2017-12-01 15:03 ` Ard Biesheuvel
2017-12-01 17:58 ` Dave Martin
2017-12-01 18:08 ` Russell King - ARM Linux
2017-12-01 18:24 ` Dave Martin
2017-12-01 19:20 ` Ard Biesheuvel
2017-12-04 9:21 ` Sebastian Andrzej Siewior
2017-12-01 17:14 ` Peter Zijlstra
2017-12-01 17:31 ` Russell King - ARM Linux
2017-12-01 17:39 ` Peter Zijlstra
2017-11-30 15:19 ` [PATCH RT] crypto: limit more FPU-enabled sections Steven Rostedt
2017-11-30 15:22 ` Sebastian Andrzej Siewior
2017-12-01 10:44 ` [PATCH RT v2] " Sebastian Andrzej Siewior
2017-12-01 11:32 ` Peter Zijlstra
2017-12-01 13:32 ` Sebastian Andrzej Siewior [this message]
2017-12-01 13:44 ` Peter Zijlstra
2017-12-01 13:50 ` Sebastian Andrzej Siewior
2017-12-01 14:03 ` [PATCH RT v3] " Sebastian Andrzej Siewior
2017-11-30 15:29 ` [PATCH RT] " Steven Rostedt
2017-11-30 15:41 ` Sebastian Andrzej Siewior
2017-11-30 16:18 ` Steven Rostedt
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=20171201133256.GE1612@linutronix.de \
--to=bigeasy@linutronix.de \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rt-users@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
/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).