[{"id":3674046,"web_url":"http://patchwork.ozlabs.org/comment/3674046/","msgid":"<20260407095955.GO2872@noisy.programming.kicks-ass.net>","list_archive_url":null,"date":"2026-04-07T09:59:55","subject":"Re: [patch 03/12] hrtimer: Use hrtimer_start_expires_user() for\n hrtimer sleepers","submitter":{"id":493,"url":"http://patchwork.ozlabs.org/api/people/493/","name":"Peter Zijlstra","email":"peterz@infradead.org"},"content":"On Tue, Apr 07, 2026 at 10:54:27AM +0200, Thomas Gleixner wrote:\n> Most hrtimer sleepers are user controlled and user space can hand arbitrary\n> expiry values in as long as they are valid timespecs. If the expiry value\n> is in the past then this requires a full loop through reprogramming the\n> clock event device, taking the hrtimer interrupt, waking the task and\n> reprogram again.\n> \n> Use hrtimer_start_expires_user() which avoids the full round trip by\n> checking the timer for expiry on enqueue.\n> \n> Signed-off-by: Thomas Gleixner \n> Cc: Anna-Maria Behnsen \n> Cc: Frederic Weisbecker \n\nAcked-by: Peter Zijlstra (Intel) \n\n> ---\n> kernel/time/hrtimer.c | 6 +++++-\n> 1 file changed, 5 insertions(+), 1 deletion(-)\n> \n> --- a/kernel/time/hrtimer.c\n> +++ b/kernel/time/hrtimer.c\n> @@ -2152,7 +2152,11 @@ void hrtimer_sleeper_start_expires(struc\n> \tif (IS_ENABLED(CONFIG_PREEMPT_RT) && sl->timer.is_hard)\n> \t\tmode |= HRTIMER_MODE_HARD;\n> \n> -\thrtimer_start_expires(&sl->timer, mode);\n> +\t/* If already expired, clear the task pointer and set current state to running */\n> +\tif (!hrtimer_start_expires_user(&sl->timer, mode)) {\n> +\t\tsl->task = NULL;\n> +\t\t__set_current_state(TASK_RUNNING);\n> +\t}\n> }\n> EXPORT_SYMBOL_GPL(hrtimer_sleeper_start_expires);\n> \n>","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","netfilter-devel@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n secure) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256\n header.s=casper.20170209 header.b=wZeNWmtu;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c04:e001:36c::12fc:5321; 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b=wZeNWmtuROtU65+wwVqZ0FC6Lu\n\ta63CxLEutuH+xWOBzloX+ZCcawzFnqMVTUVMkCrr8pp0FuRMmXJtUVuUmc+yIVOajP1H4NNDkZ9Lq\n\tXlHrUlLAXfRJ8kQzA5hN0u3DEuT72627noPDJXvEl2qx4X/vOpBp8L6ROxsWloRXUA8VeiipIrtSg\n\t2WrkgaEI45oHXO4Zb/pwfMwpUMpjrOhBwCKIiC3Wxs+rMHPxEIN3oafgKIEGAm2AiCTF5Tke2P3+1\n\tlfaQaJdlQvkqUoSZnG0qjOuBMFZ/F6lms48dJ812zMLZWKh10z6E4jwLuStQX+kSHxT6iVPYFpH9T\n\tMy5B0nKg==;","Date":"Tue, 7 Apr 2026 11:59:55 +0200","From":"Peter Zijlstra ","To":"Thomas Gleixner ","Cc":"LKML ,\n\tAnna-Maria Behnsen ,\n\tFrederic Weisbecker ,\n\tCalvin Owens , Ingo Molnar ,\n\tJohn Stultz , Stephen Boyd ,\n\tAlexander Viro ,\n\tChristian Brauner , Jan Kara ,\n\tlinux-fsdevel@vger.kernel.org, Sebastian Reichel ,\n\tlinux-pm@vger.kernel.org, Pablo Neira Ayuso ,\n\tFlorian Westphal , Phil Sutter ,\n\tnetfilter-devel@vger.kernel.org, coreteam@netfilter.org","Subject":"Re: [patch 03/12] hrtimer: Use hrtimer_start_expires_user() for\n hrtimer sleepers","Message-ID":"<20260407095955.GO2872@noisy.programming.kicks-ass.net>","References":"<20260407083219.478203185@kernel.org>\n <20260407083247.696142908@kernel.org>","Precedence":"bulk","X-Mailing-List":"netfilter-devel@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","Content-Type":"text/plain; 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