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([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id x81sm2920137wmb.11.2020.10.27.11.50.14 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 27 Oct 2020 11:50:14 -0700 (PDT) Subject: Re: [PATCH 3/3] sched: Add cond_resched_rwlock To: Peter Zijlstra , Ben Gardon Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Sean Christopherson , Peter Shier , Ingo Molnar , Will Deacon , Waiman Long , Davidlohr Bueso References: <20201027164950.1057601-1-bgardon@google.com> <20201027164950.1057601-3-bgardon@google.com> <20201027184440.GN2628@hirez.programming.kicks-ass.net> From: Paolo Bonzini Message-ID: <31db67e0-bd9f-ff6d-2cee-b60ad52f71b2@redhat.com> Date: Tue, 27 Oct 2020 19:50:14 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.3.1 MIME-Version: 1.0 In-Reply-To: <20201027184440.GN2628@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 27/10/20 19:44, Peter Zijlstra wrote: > On Tue, Oct 27, 2020 at 09:49:50AM -0700, Ben Gardon wrote: > >> diff --git a/kernel/sched/core.c b/kernel/sched/core.c >> index d2003a7d5ab55..ac58e7829a063 100644 >> --- a/kernel/sched/core.c >> +++ b/kernel/sched/core.c >> @@ -6152,6 +6152,46 @@ int __cond_resched_lock(spinlock_t *lock) >> } >> EXPORT_SYMBOL(__cond_resched_lock); >> >> +int __cond_resched_rwlock_read(rwlock_t *lock) >> +{ >> + int resched = should_resched(PREEMPT_LOCK_OFFSET); >> + int ret = 0; >> + >> + lockdep_assert_held(lock); > > lockdep_assert_held_read(lock); > >> + >> + if (rwlock_needbreak(lock) || resched) { >> + read_unlock(lock); >> + if (resched) >> + preempt_schedule_common(); >> + else >> + cpu_relax(); >> + ret = 1; >> + read_lock(lock); >> + } >> + return ret; >> +} >> +EXPORT_SYMBOL(__cond_resched_rwlock_read); >> + >> +int __cond_resched_rwlock_write(rwlock_t *lock) >> +{ >> + int resched = should_resched(PREEMPT_LOCK_OFFSET); >> + int ret = 0; >> + >> + lockdep_assert_held(lock); > > lockdep_assert_held_write(lock); > >> + >> + if (rwlock_needbreak(lock) || resched) { >> + write_unlock(lock); >> + if (resched) >> + preempt_schedule_common(); >> + else >> + cpu_relax(); >> + ret = 1; >> + write_lock(lock); >> + } >> + return ret; >> +} >> +EXPORT_SYMBOL(__cond_resched_rwlock_write); > > If this is the only feedback (the patches look fine to me), don't bother > resending, I'll edit them when applying. > If that is an Acked-by, I'll merge them through the KVM tree when time comes. Paolo