From: Al Viro <viro@zeniv.linux.org.uk>
To: David Laight <David.Laight@aculab.com>
Cc: 'Pavel Begunkov' <asml.silence@gmail.com>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Jens Axboe <axboe@kernel.dk>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] iov_iter: optimise iter type checking
Date: Wed, 27 Jan 2021 18:30:34 +0000 [thread overview]
Message-ID: <20210127183034.GO740243@zeniv-ca> (raw)
In-Reply-To: <6f7ba1dbbc4749f09ae44aafc6ada284@AcuMS.aculab.com>
On Wed, Jan 27, 2021 at 04:28:38PM +0000, David Laight wrote:
> I'd definitely leave the type as a bitmap.
What the hell for? Microoptimizations in places where we have
much heavier stuff to be done are bloody pointless.
It's already overcomplicated. And compiler is _not_ going to
be able to prove that we'll only ever have one bit set, so
you would be making it harder to optimize, not to mention
reason about.
next prev parent reply other threads:[~2021-01-27 18:31 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-21 14:37 [PATCH] iov_iter: optimise iter type checking Pavel Begunkov
2020-12-06 16:01 ` Pavel Begunkov
2021-01-09 16:09 ` Pavel Begunkov
2021-01-09 17:03 ` Al Viro
2021-01-09 21:19 ` Pavel Begunkov
2021-01-09 21:49 ` David Laight
2021-01-09 22:11 ` Pavel Begunkov
2021-01-11 9:35 ` David Laight
2021-01-12 16:04 ` Pavel Begunkov
2021-01-16 5:18 ` Al Viro
2021-01-17 12:12 ` David Laight
2021-01-27 15:48 ` Pavel Begunkov
2021-01-27 16:28 ` David Laight
2021-01-27 18:30 ` Al Viro [this message]
2021-01-27 18:31 ` Al Viro
2021-01-28 11:39 ` Pavel Begunkov
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