From: Davidlohr Bueso <dave@stgolabs.net>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Ben Gardon <bgardon@google.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Paolo Bonzini <pbonzini@redhat.com>,
Peter Shier <pshier@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
Waiman Long <longman@redhat.com>
Subject: Re: [PATCH 3/3] sched: Add cond_resched_rwlock
Date: Tue, 27 Oct 2020 13:17:30 -0700 [thread overview]
Message-ID: <20201027201730.kyusnssnrict75bh@linux-p48b.lan> (raw)
In-Reply-To: <20201027175634.GI1021@linux.intel.com>
On Tue, 27 Oct 2020, Sean Christopherson wrote:
>On Tue, Oct 27, 2020 at 09:49:50AM -0700, Ben Gardon wrote:
>> Rescheduling while holding a spin lock is essential for keeping long
>> running kernel operations running smoothly. Add the facility to
>> cond_resched rwlocks.
Nit: I would start the paragraph with 'Safely rescheduling ...'
While obvious when reading the code, 'Rescheduling while holding
a spin lock' can throw the reader off.
>
>This adds two new exports and two new macros without any in-tree users, which
>is generally frowned upon. You and I know these will be used by KVM's new
>TDP MMU, but the non-KVM folks, and more importantly the maintainers of this
>code, are undoubtedly going to ask "why". I.e. these patches probably belong
>in the KVM series to switch to a rwlock for the TDP MMU.
>
>Regarding the code, it's all copy-pasted from the spinlock code and darn near
>identical. It might be worth adding builder macros for these.
Agreed, all three could be nicely consolidated. Otherwise this series looks
sane, feel free to add my:
Acked-by: Davidlohr Bueso <dbueso@suse.de>
next prev parent reply other threads:[~2020-10-27 20:38 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-27 16:49 [PATCH 1/3] locking/rwlocks: Add contention detection for rwlocks Ben Gardon
2020-10-27 16:49 ` [PATCH 2/3] sched: Add needbreak " Ben Gardon
2020-10-27 16:49 ` [PATCH 3/3] sched: Add cond_resched_rwlock Ben Gardon
2020-10-27 17:56 ` Sean Christopherson
2020-10-27 19:17 ` Peter Zijlstra
2020-10-27 20:17 ` Davidlohr Bueso [this message]
2020-10-27 18:44 ` Peter Zijlstra
2020-10-27 18:50 ` Paolo Bonzini
2020-10-30 17:09 ` Waiman Long
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