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Date:   Mon, 23 Nov 2020 08:05:06 +0000
From:   Christoph Hellwig <hch@infradead.org>
To:     David Howells <dhowells@redhat.com>
Cc:     Pavel Begunkov <asml.silence@gmail.com>,
        Matthew Wilcox <willy@infradead.org>,
        Jens Axboe <axboe@kernel.dk>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 01/29] iov_iter: Switch to using a table of operations
Message-ID: <20201123080506.GA30578@infradead.org>
References: <160596800145.154728.7192318545120181269.stgit@warthog.procyon.org.uk>
 <160596801020.154728.15935034745159191564.stgit@warthog.procyon.org.uk>
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On Sat, Nov 21, 2020 at 02:13:30PM +0000, David Howells wrote:
> Switch to using a table of operations.  In a future patch the individual
> methods will be split up by type.  For the moment, however, the ops tables
> just jump directly to the old functions - which are now static.  Inline
> wrappers are provided to jump through the hooks.
> 
> Signed-off-by: David Howells <dhowells@redhat.com>

Please run performance tests.  I think the indirect calls could totally
wreck things like high performance direct I/O, especially using io_uring
on x86.