linux-kernel - Re: [PATCH 2/2] mm/slab: break up RCU readers on SLAB_TYPESAFE_BY

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Message-Id: <20230415030452.3223-1-sj@kernel.org>
Date:   Sat, 15 Apr 2023 03:04:52 +0000
From:   SeongJae Park <sj@...nel.org>
To:     Matthew Wilcox <willy@...radead.org>
Cc:     SeongJae Park <sj@...nel.org>, akpm@...ux-foundation.org,
        vbabka@...e.cz, linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] mm/slab: break up RCU readers on SLAB_TYPESAFE_BY_RCU example code

On Sat, 15 Apr 2023 03:51:54 +0100 Matthew Wilcox <willy@...radead.org> wrote:

> On Sat, Apr 15, 2023 at 12:37:53AM +0000, SeongJae Park wrote:
> >   *
> > + * begin:
> >   *  rcu_read_lock();
> > - * again:
> >   *  obj = lockless_lookup(key);
> >   *  if (obj) {
> >   *    if (!try_get_ref(obj)) // might fail for free objects
> > - *      goto again;
> > + *      goto begin;
> >   *
> >   *    if (obj->key != key) { // not the object we expected
> >   *      put_ref(obj);
> > + *      rcu_read_unlock();
> >   *      goto again;
> 
> - *      goto again;
> + *      goto begin;

Oops, thank you for catching, Matthew!


Thanks,
SJ