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From:   Eric Dumazet <edumazet@google.com>
Date:   Fri, 17 Jun 2022 21:10:05 +0200
Message-ID: <CANn89iKO1koPa5R_mvK0k2dkFaq+F0PgcbvpVt+JpzzR5xsu6g@mail.gmail.com>
Subject: Re: [PATCH] locking/rwlocks: do not starve writers
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Waiman Long <longman@redhat.com>,
        Shakeel Butt <shakeelb@google.com>,
        Eric Dumazet <eric.dumazet@gmail.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@redhat.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        Will Deacon <will@kernel.org>, Roman Penyaev <rpenyaev@suse.de>
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On Fri, Jun 17, 2022 at 9:04 PM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Fri, Jun 17, 2022 at 07:45:14PM +0200, Eric Dumazet wrote:
>
> > Were rwlocks always unfair, and we have been lucky ?
>
> Yes.

So I wonder why we replaced eventpoll spinlock with an rwlock.

Writing a repro is probably more difficult for eventpoll though.

We definitely had production issues after commit a218cc491420