Date: Mon, 23 Feb 2015 00:13:58 +0000 From: "kmacy (Kip Macy)" <phabric-noreply@FreeBSD.org> To: freebsd-arm@freebsd.org Subject: [Differential] [Commented On] D1833: Add memory barriers to buf_ring Message-ID: <86f2bf07aa933a7a1898696286dd8a5c@localhost.localdomain> In-Reply-To: <differential-rev-PHID-DREV-ntnotl4wj5wcj2eoukly-req@FreeBSD.org> References: <differential-rev-PHID-DREV-ntnotl4wj5wcj2eoukly-req@FreeBSD.org>
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kmacy added a comment. Reading this again, cons_head is used only by dequeue and is thus protected by the lock or an atomic update. Hence the atomic_load_acq_32 isn't needed for it. On the other hand, there are other places where prod_tail needs to be read with a memory barrier. REVISION DETAIL https://reviews.freebsd.org/D1833 To: zbb, kmacy, rpaulo, imp Cc: meloun-miracle-cz, onwahe-gmail-com, andrew, ian, adrian, freebsd-arm
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