From mboxrd@z Thu Jan 1 00:00:00 1970 From: peterz@infradead.org (Peter Zijlstra) Date: Thu, 15 Mar 2018 09:27:21 +0100 Subject: Do we need to disable preemption in flush_tlb_range()? In-Reply-To: <5a5c67c1-9f45-f908-2c8d-0914cd616a18@synopsys.com> References: <1519917189.13866.6.camel@synopsys.com> <5a5c67c1-9f45-f908-2c8d-0914cd616a18@synopsys.com> List-ID: Message-ID: <20180315082720.GT4064@hirez.programming.kicks-ass.net> To: linux-snps-arc@lists.infradead.org On Wed, Mar 14, 2018@01:19:01PM -0700, Vineet Gupta wrote: > +CC Peter since we have his attention ;-) Yeah, timezone collision there, I typically sleep at 1am ;-) > On 03/01/2018 07:13 AM, Alexey Brodkin wrote: > > Hi Vineet, > > > > Just noticed that in comments for smp_call_function_many() it is said that > > preemption must be disabled during its execution. And that function gets executed > > among other ways like that: > > -------------------------->8----------------------- > > flush_tlb_range() > > -> on_each_cpu_mask() > > -> smp_call_function_many() > > -------------------------->8----------------------- > > In general I prefer not to - Peter what say you ? The comment with smp_call_function_many() is correct, it relies on preemption being disabled in a number of ways. I would expect this_cpu_ptr() for example to complain when used with preemption enabled (CONFIG_DEBUG_PREEMPT).