From: David Laight <david.laight.linux@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: David Laight <david.laight.linux@gmail.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Jens Axboe <axboe@kernel.dk>, David Howells <dhowells@redhat.com>,
Matthew Wilcox <willy@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>
Subject: [PATCH next 0/3] iov: Optimise user copies
Date: Fri, 21 Mar 2025 22:45:54 +0000 [thread overview]
Message-ID: <20250321224557.3847-1-david.laight.linux@gmail.com> (raw)
The speculation barrier in access_ok() is expensive.
The first patch removes the initial checks when reading the iovec[].
The checks are repeated before the actual copy.
The second patch uses 'user address masking' if supported.
The third removes a lot of code for single entry iovec[].
David Laight (3):
Remove access_ok() from import_iovec()
Use masked user accesses
Optimise __import_iovec_ubuf()
lib/iov_iter.c | 97 ++++++++++++++++++++++++++++++++------------------
1 file changed, 63 insertions(+), 34 deletions(-)
--
2.39.5
next reply other threads:[~2025-03-21 22:46 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-21 22:45 David Laight [this message]
2025-03-21 22:45 ` [PATCH next 1/3] iov: Remove access_ok() from import_iovec() David Laight
2025-03-21 22:45 ` [PATCH next 2/3] iov: Use masked user accesses David Laight
2025-03-21 22:45 ` [PATCH next 3/3] iov: Optimise __import_iovec_ubuf() David Laight
2025-03-21 23:35 ` [PATCH next 0/3] iov: Optimise user copies Linus Torvalds
2025-03-22 10:08 ` David Laight
2025-03-22 22:37 ` David Laight
2025-03-29 11:31 ` David Laight
2025-03-22 14:36 ` Jens Axboe
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