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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: willy@infradead.org
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, cl@linux.com,
	penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com,
	akpm@linux-foundation.org
Subject: Re: [PATCH RFC] mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU
Date: Wed, 18 Jan 2017 14:17:37 -0800	[thread overview]
Message-ID: <20170118221737.GP5238@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170118111201.GB29472@bombadil.infradead.org>

On Wed, Jan 18, 2017 at 03:12:01AM -0800, willy@infradead.org wrote:
> On Wed, Jan 18, 2017 at 03:07:32AM -0800, Paul E. McKenney wrote:
> > A group of Linux kernel hackers reported chasing a bug that resulted
> > from their assumption that SLAB_DESTROY_BY_RCU provided an existence
> > guarantee, that is, that no block from such a slab would be reallocated
> > during an RCU read-side critical section.  Of course, that is not the
> > case.  Instead, SLAB_DESTROY_BY_RCU only prevents freeing of an entire
> > slab of blocks.
> > 
> > However, there is a phrase for this, namely "type safety".  This commit
> > therefore renames SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU in order
> > to avoid future instances of this sort of confusion.
> 
> This is probably the ultimate in bikeshedding, but RCU is not the
> thing which is providing the typesafety.  Slab is providing the
> typesafety in order to help RCU.  So would a better name not be
> 'SLAB_TYPESAFETY_FOR_RCU', or more succinctly 'SLAB_RCU_TYPESAFE'?

Actually, slab is using RCU to provide type safety to those slab users
who request it.

							Thanx, Paul

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  reply	other threads:[~2017-01-18 22:29 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-18 11:07 Paul E. McKenney
2017-01-18 11:12 ` willy
2017-01-18 22:17   ` Paul E. McKenney [this message]
2017-01-19  0:00     ` Christoph Lameter
2017-01-23  0:46       ` Paul E. McKenney
2017-01-25 16:45         ` Christoph Lameter
2017-01-25 17:04           ` Eric Dumazet
2017-01-25 20:07             ` Paul E. McKenney
2017-01-25 22:46               ` Eric Dumazet
2017-01-25 23:05                 ` Paul E. McKenney
2017-01-25 20:25 ` Johannes Weiner
2017-01-25 21:26   ` Vlastimil Babka
2017-01-25 22:35     ` Paul E. McKenney

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