From: Jakub Kicinski <kuba@kernel.org>
To: Alexander Lobakin <aleksander.lobakin@intel.com>
Cc: Yury Norov <yury.norov@gmail.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Alexander Potapenko <glider@google.com>,
Eric Dumazet <edumazet@google.com>,
David Ahern <dsahern@kernel.org>,
Przemek Kitszel <przemyslaw.kitszel@intel.com>,
Simon Horman <simon.horman@corigine.com>,
netdev@vger.kernel.org, linux-btrfs@vger.kernel.org,
dm-devel@redhat.com, ntfs3@lists.linux.dev,
linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 04/13] linkmode: convert linkmode_{test,set,clear,mod}_bit() to macros
Date: Wed, 18 Oct 2023 17:27:54 -0700 [thread overview]
Message-ID: <20231018172754.3eec4885@kernel.org> (raw)
In-Reply-To: <20231016165247.14212-5-aleksander.lobakin@intel.com>
On Mon, 16 Oct 2023 18:52:38 +0200 Alexander Lobakin wrote:
> Since commit b03fc1173c0c ("bitops: let optimize out non-atomic bitops
> on compile-time constants"), the non-atomic bitops are macros which can
> be expanded by the compilers into compile-time expressions, which will
> result in better optimized object code. Unfortunately, turned out that
> passing `volatile` to those macros discards any possibility of
> optimization, as the compilers then don't even try to look whether
> the passed bitmap is known at compilation time. In addition to that,
> the mentioned linkmode helpers are marked with `inline`, not
> `__always_inline`, meaning that it's not guaranteed some compiler won't
> uninline them for no reason, which will also effectively prevent them
> from being optimized (it's a well-known thing the compilers sometimes
> uninline `2 + 2`).
> Convert linkmode_*_bit() from inlines to macros. Their calling
> convention are 1:1 with the corresponding bitops, so that it's not even
> needed to enumerate and map the arguments, only the names. No changes in
> vmlinux' object code (compiled by LLVM for x86_64) whatsoever, but that
> doesn't necessarily means the change is meaningless.
Acked-by: Jakub Kicinski <kuba@kernel.org>
This one can go in with the rest, it's trivial enough.
next prev parent reply other threads:[~2023-10-19 0:28 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-16 16:52 [PATCH v2 00/13] ip_tunnel: convert __be16 tunnel flags to bitmaps Alexander Lobakin
2023-10-16 16:52 ` [PATCH v2 01/13] bitops: add missing prototype check Alexander Lobakin
2023-10-16 16:52 ` [PATCH v2 02/13] bitops: make BYTES_TO_BITS() treewide-available Alexander Lobakin
2023-10-16 16:52 ` [PATCH v2 03/13] bitops: let the compiler optimize {__,}assign_bit() Alexander Lobakin
2023-10-16 16:52 ` [PATCH v2 04/13] linkmode: convert linkmode_{test,set,clear,mod}_bit() to macros Alexander Lobakin
2023-10-19 0:27 ` Jakub Kicinski [this message]
2023-10-16 16:52 ` [PATCH v2 05/13] s390/cio: rename bitmap_size() -> idset_bitmap_size() Alexander Lobakin
2023-10-16 16:52 ` [PATCH v2 06/13] fs/ntfs3: add prefix to bitmap_size() and use BITS_TO_U64() Alexander Lobakin
2023-10-16 16:52 ` [PATCH v2 07/13] btrfs: rename bitmap_set_bits() -> btrfs_bitmap_set_bits() Alexander Lobakin
2023-10-16 16:52 ` [PATCH v2 08/13] bitmap: introduce generic optimized bitmap_size() Alexander Lobakin
2023-10-16 16:52 ` [PATCH v2 09/13] bitmap: make bitmap_{get,set}_value8() use bitmap_{read,write}() Alexander Lobakin
2023-10-16 17:48 ` Yury Norov
2023-10-16 16:52 ` [PATCH v2 10/13] ip_tunnel: use a separate struct to store tunnel params in the kernel Alexander Lobakin
2023-10-16 16:52 ` [PATCH v2 11/13] ip_tunnel: convert __be16 tunnel flags to bitmaps Alexander Lobakin
2023-10-19 0:27 ` Jakub Kicinski
2023-10-20 7:41 ` Alexander Potapenko
2023-10-20 12:30 ` Yury Norov
2023-11-02 11:48 ` Alexander Lobakin
2023-10-16 16:52 ` [PATCH v2 12/13] lib/bitmap: add compile-time test for __assign_bit() optimization Alexander Lobakin
2023-10-16 16:52 ` [PATCH v2 13/13] lib/bitmap: add tests for IP tunnel flags conversion helpers Alexander Lobakin
2023-10-16 17:54 ` [PATCH v2 00/13] ip_tunnel: convert __be16 tunnel flags to bitmaps Yury Norov
2023-10-20 12:46 ` Yury Norov
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