From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Rutland Subject: Re: [PATCH 25/36] time/tick-broadcast: Remove RCU_NONIDLE usage Date: Tue, 14 Jun 2022 17:28:02 +0100 Message-ID: References: <20220608142723.103523089@infradead.org> <20220608144517.507286638@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20220608144517.507286638@infradead.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" To: Peter Zijlstra Cc: juri.lelli@redhat.com, rafael@kernel.org, benh@kernel.crashing.org, linus.walleij@linaro.org, bsegall@google.com, guoren@kernel.org, pavel@ucw.cz, agordeev@linux.ibm.com, linux-arch@vger.kernel.org, vincent.guittot@linaro.org, mpe@ellerman.id.au, chenhuacai@kernel.org, linux-acpi@vger.kernel.org, agross@kernel.org, geert@linux-m68k.org, linux-imx@nxp.com, catalin.marinas@arm.com, xen-devel@lists.xenproject.org, mattst88@gmail.com, mturquette@baylibre.com, sammy@sammy.net, pmladek@suse.com, linux-pm@vger.kernel.org, jiangshanlai@gmail.com, Sascha Hauer , linux-um@lists.infradead.org, acme@kernel.org, tglx@linutronix.de, linux-omap@vger.kernel.org, dietmar.eggemann@arm.com, rth@twiddle.net, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, senozhatsky@chromium.org, svens@linux.ibm.com, jolsa@kernel.org, paul On Wed, Jun 08, 2022 at 04:27:48PM +0200, Peter Zijlstra wrote: > No callers left that have already disabled RCU. > > Signed-off-by: Peter Zijlstra (Intel) Acked-by: Mark Rutland Mark. > --- > kernel/time/tick-broadcast-hrtimer.c | 29 ++++++++++++----------------- > 1 file changed, 12 insertions(+), 17 deletions(-) > > --- a/kernel/time/tick-broadcast-hrtimer.c > +++ b/kernel/time/tick-broadcast-hrtimer.c > @@ -56,25 +56,20 @@ static int bc_set_next(ktime_t expires, > * hrtimer callback function is currently running, then > * hrtimer_start() cannot move it and the timer stays on the CPU on > * which it is assigned at the moment. > + */ > + hrtimer_start(&bctimer, expires, HRTIMER_MODE_ABS_PINNED_HARD); > + /* > + * The core tick broadcast mode expects bc->bound_on to be set > + * correctly to prevent a CPU which has the broadcast hrtimer > + * armed from going deep idle. > * > - * As this can be called from idle code, the hrtimer_start() > - * invocation has to be wrapped with RCU_NONIDLE() as > - * hrtimer_start() can call into tracing. > + * As tick_broadcast_lock is held, nothing can change the cpu > + * base which was just established in hrtimer_start() above. So > + * the below access is safe even without holding the hrtimer > + * base lock. > */ > - RCU_NONIDLE( { > - hrtimer_start(&bctimer, expires, HRTIMER_MODE_ABS_PINNED_HARD); > - /* > - * The core tick broadcast mode expects bc->bound_on to be set > - * correctly to prevent a CPU which has the broadcast hrtimer > - * armed from going deep idle. > - * > - * As tick_broadcast_lock is held, nothing can change the cpu > - * base which was just established in hrtimer_start() above. So > - * the below access is safe even without holding the hrtimer > - * base lock. > - */ > - bc->bound_on = bctimer.base->cpu_base->cpu; > - } ); > + bc->bound_on = bctimer.base->cpu_base->cpu; > + > return 0; > } > > >