From: Peter Zijlstra <peterz@infradead.org>
To: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
"Steven Rostedt (VMware)" <rostedt@goodmis.org>,
Jiri Kosina <jkosina@suse.cz>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Chris von Recklinghausen <crecklin@redhat.com>,
Jason Baron <jbaron@akamai.com>, Scott Wood <swood@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Clark Williams <williams@redhat.com>,
x86@kernel.org
Subject: Re: [PATCH V5 6/7] jump_label: Batch updates if arch supports it
Date: Mon, 15 Apr 2019 13:50:45 +0200 [thread overview]
Message-ID: <20190415115045.GL11158@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <3fbdeb0d8c19968f4a2e2af17a872a31b9a4adcf.1554106794.git.bristot@redhat.com>
On Mon, Apr 01, 2019 at 10:58:18AM +0200, Daniel Bristot de Oliveira wrote:
> +int fallback_batch __read_mostly;
> +static void __jump_label_update(struct static_key *key,
> + struct jump_entry *entry,
> + struct jump_entry *stop,
> + bool init)
> +{
> + for_each_label_entry(key, entry, stop) {
> +
> + if (!jump_label_can_update(entry, init))
> + continue;
> +
> + if (unlikely(fallback_batch)) {
> + arch_jump_label_transform(entry, jump_label_type(entry));
> + continue;
> + }
> +
> + if (!arch_jump_label_transform_queue(entry, jump_label_type(entry)))
> + continue;
That reads wrong; 'if we cannot queue, continue'
> +
> + /*
> + * Queue's overflow: Apply the current queue, and then try to
> + * queue again. If it stills fail to queue, fallback to the
> + * non-batch mode!
> + */
> + arch_jump_label_transform_apply();
> +
> + if (arch_jump_label_transform_queue(entry, jump_label_type(entry))) {
> + WARN(1, "jump_label: batch mode failure!\n");
> + fallback_batch = 1;
> + arch_jump_label_transform(entry, jump_label_type(entry));
> + }
> + }
> + arch_jump_label_transform_apply();
> +}
Hurmph...
for_each_whatever(entry, stop, key) {
if (!jump_label_can_update(entry, init))
continue;
if (!arch_jump_label_transform_queue(entry)) {
/* queue full, flush */
arch_jump_label_transform_apply();
BUG_ON(!arch_jump_label_transform_queue(entry));
}
}
arch_jump_label_transform_apply();
Also, see next patch.
next prev parent reply other threads:[~2019-04-15 11:51 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-01 8:58 [PATCH V5 0/7] x86/jump_label: Bound IPIs sent when updating a static key Daniel Bristot de Oliveira
2019-04-01 8:58 ` [PATCH V5 1/7] jump_label: Add for_each_label_entry helper Daniel Bristot de Oliveira
2019-04-15 10:51 ` Peter Zijlstra
2019-04-15 11:29 ` Daniel Bristot de Oliveira
2019-04-01 8:58 ` [PATCH V5 2/7] jump_label: Add a jump_label_can_update() helper Daniel Bristot de Oliveira
2019-04-01 8:58 ` [PATCH V5 3/7] x86/jump_label: Add a __jump_label_set_jump_code() helper Daniel Bristot de Oliveira
2019-04-01 8:58 ` [PATCH V5 4/7] jump_label: Sort entries of the same key by the code Daniel Bristot de Oliveira
2019-04-15 10:55 ` Peter Zijlstra
2019-04-15 11:33 ` Daniel Bristot de Oliveira
2019-04-01 8:58 ` [PATCH V5 5/7] x86/alternative: Batch of patch operations Daniel Bristot de Oliveira
2019-04-15 11:35 ` Peter Zijlstra
2019-04-01 8:58 ` [PATCH V5 6/7] jump_label: Batch updates if arch supports it Daniel Bristot de Oliveira
2019-04-15 11:50 ` Peter Zijlstra [this message]
2019-04-01 8:58 ` [PATCH V5 7/7] x86/jump_label: Batch jump label updates Daniel Bristot de Oliveira
2019-04-15 11:54 ` Peter Zijlstra
2019-04-15 12:15 ` Daniel Bristot de Oliveira
2019-05-02 20:18 ` Daniel Bristot de Oliveira
2019-04-15 9:52 ` [PATCH V5 0/7] x86/jump_label: Bound IPIs sent when updating a static key Daniel Bristot de Oliveira
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