From: Dominique Martinet <asmadeus@codewreck.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: v9fs-developer@lists.sourceforge.net,
Latchesar Ionkov <lucho@ionkov.net>,
Eric Van Hensbergen <ericvh@gmail.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Ron Minnich <rminnich@sandia.gov>
Subject: Re: [V9fs-developer] [PATCH 4/6] 9p: Remove an unnecessary memory barrier
Date: Thu, 28 Jun 2018 16:33:23 +0200 [thread overview]
Message-ID: <20180628143323.GA32547@nautica> (raw)
In-Reply-To: <20180628140358.GG7646@bombadil.infradead.org>
Matthew Wilcox wrote on Thu, Jun 28, 2018:
> How about this?
>
> /*
> * This barrier is needed to make sure any change made to req before
> - * the other thread wakes up will indeed be seen by the waiting side.
> + * the status change is visible to another thread
> */
Yes, that sounds better.
This code is fairly old and I was wondering if the new WRITE_ONCE and
READ_ONCE macros would help but it looks like compile-time barriers only
so I do not think they would be enough...
Documentation/memory-barriers.txt still suggests something similar in
the "SLEEP AND WAKE-UP FUNCTIONS" section so I guess this is fine.
Thanks,
--
Dominique Martinet | Asmadeus
next prev parent reply other threads:[~2018-06-28 14:33 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-28 13:26 [PATCH 0/6] 9p: Use IDRs more effectively Matthew Wilcox
2018-06-28 13:26 ` [PATCH 1/6] 9p: Change p9_fid_create calling convention Matthew Wilcox
2018-06-28 13:26 ` [PATCH 2/6] 9p: Replace the fidlist with an IDR Matthew Wilcox
2018-07-11 12:40 ` [V9fs-developer] " Dominique Martinet
2018-07-11 12:52 ` Matthew Wilcox
2018-07-11 12:58 ` Dominique Martinet
2018-07-11 13:08 ` Matthew Wilcox
2018-06-28 13:26 ` [PATCH 3/6] 9p: Embed wait_queue_head into p9_req_t Matthew Wilcox
2018-06-28 13:26 ` [PATCH 4/6] 9p: Remove an unnecessary memory barrier Matthew Wilcox
2018-06-28 13:40 ` [V9fs-developer] " Dominique Martinet
2018-06-28 14:03 ` Matthew Wilcox
2018-06-28 14:33 ` Dominique Martinet [this message]
2018-06-28 13:26 ` [PATCH 5/6] 9p: Use a slab for allocating requests Matthew Wilcox
2018-07-11 13:33 ` [V9fs-developer] " Dominique Martinet
2018-07-11 14:13 ` Matthew Wilcox
2018-07-11 14:24 ` Dominique Martinet
2018-06-28 13:26 ` [PATCH 6/6] 9p: Remove p9_idpool Matthew Wilcox
2018-07-11 13:38 ` [V9fs-developer] [PATCH 0/6] 9p: Use IDRs more effectively Dominique Martinet
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