From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v2] kref: warn on uninitialized kref
Date: Mon, 19 May 2014 10:19:46 +0200
Message-ID: <20140519081946.GV30445@twins.programming.kicks-ass.net>
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To: Mikulas Patocka <mpatocka@redhat.com>
Cc: Bart Van Assche <bvanassche@acm.org>, Mateusz Guzik <mguzik@redhat.com>, Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org, "Nicholas A. Bellinger" <nab@linux-iscsi.org>, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org
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On Sat, May 17, 2014 at 05:14:13PM -0400, Mikulas Patocka wrote:
> BTW. if we talk about performance - what about replacing:
>=20
> 	if (atomic_dec_and_test(&variable)) {
> 		... release(object);
> 	}
>=20
> with this:
>=20
> 	if (atomic_read(&variable) =3D=3D 1 || atomic_dec_and_test(&variable)) {
> 		barrier();
> 		... release(object);
> 	}

That would completely wreck kref_get_unless_zero().

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