From: Andrzej Hajda <andrzej.hajda@intel.com>
To: linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-snps-arc@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
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dri-devel@lists.freedesktop.org
Cc: Andrzej Hajda <andrzej.hajda@intel.com>,
Arnd Bergmann <arnd@arndb.de>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Boqun Feng <boqun.feng@gmail.com>,
Mark Rutland <mark.rutland@arm.com>
Subject: [PATCH 00/19] Introduce __xchg, non-atomic xchg
Date: Thu, 22 Dec 2022 12:46:16 +0100 [thread overview]
Message-ID: <20221222114635.1251934-1-andrzej.hajda@intel.com> (raw)
Hi all,
I hope there will be place for such tiny helper in kernel.
Quick cocci analyze shows there is probably few thousands places
where it could be useful.
I am not sure who is good person to review/ack such patches,
so I've used my intuition to construct to/cc lists, sorry for mistakes.
This is the 2nd approach of the same idea, with comments addressed[0].
The helper is tiny and there are advices we can leave without it, so
I want to present few arguments why it would be good to have it:
1. Code readability/simplification/number of lines:
Real example from drivers/net/ethernet/mellanox/mlx5/core/esw/qos.c:
- previous_min_rate = evport->qos.min_rate;
- evport->qos.min_rate = min_rate;
+ previous_min_rate = __xchg(evport->qos.min_rate, min_rate);
For sure the code is more compact, and IMHO more readable.
2. Presence of similar helpers in other somehow related languages/libs:
a) Rust[1]: 'replace' from std::mem module, there is also 'take'
helper (__xchg(&x, 0)), which is the same as private helper in
i915 - fetch_and_zero, see latest patch.
b) C++ [2]: 'exchange' from utility header.
If the idea is OK there are still 2 qestions to answer:
1. Name of the helper, __xchg follows kernel conventions,
but for me Rust names are also OK.
2. Where to put the helper:
a) as in this patchset include/linux/non-atomic/xchg.h,
proposed by Andy Shevchenko,
b) include/linux/utils.h ? any better name? Some kind
of container for simple helpers.
Structure of the patchset:
17 patches releasing __xchg name from arch files
1 patch adding __xchg
1 patch adding users of __xchg
Arnd thanks for convienient set of cross compilers, it was very helpful.
So many words for so small helper :)
[0]: https://lore.kernel.org/lkml/Y5OFSvaYbv4XCxhE@smile.fi.intel.com/T/
[1]: https://doc.rust-lang.org/std/mem/index.html
[2]: https://en.cppreference.com/w/cpp/header/utility
Regards
Andrzej
Andrzej Hajda (19):
arch/alpha: rename internal name __xchg to __arch_xchg
arch/arc: rename internal name __xchg to __arch_xchg
arch/arm: rename internal name __xchg to __arch_xchg
arch/arm64: rename internal name __xchg to __arch_xchg
arch/hexagon: rename internal name __xchg to __arch_xchg
arch/ia64: rename internal name __xchg to __arch_xchg
arch/loongarch: rename internal name __xchg to __arch_xchg
arch/m68k: rename internal name __xchg to __arch_xchg
arch/mips: rename internal name __xchg to __arch_xchg
arch/openrisc: rename internal name __xchg to __arch_xchg
arch/parisc: rename internal name __xchg to __arch_xchg
arch/powerpc: correct logged function names in xchg helpers
arch/riscv: rename internal name __xchg to __arch_xchg
arch/s390: rename internal name __xchg to __arch_xchg
arch/sh: rename internal name __xchg to __arch_xchg
arch/sparc: rename internal name __xchg to __arch_xchg
arch/xtensa: rename internal name __xchg to __arch_xchg
linux/include: add non-atomic version of xchg
drm/i915/gt: use __xchg instead of internal helper
arch/alpha/include/asm/cmpxchg.h | 6 +++---
arch/arc/include/asm/cmpxchg.h | 4 ++--
arch/arm/include/asm/cmpxchg.h | 4 ++--
arch/arm64/include/asm/cmpxchg.h | 4 ++--
arch/hexagon/include/asm/cmpxchg.h | 6 +++---
arch/ia64/include/asm/cmpxchg.h | 2 +-
arch/ia64/include/uapi/asm/cmpxchg.h | 4 ++--
arch/loongarch/include/asm/cmpxchg.h | 4 ++--
arch/m68k/include/asm/cmpxchg.h | 6 +++---
arch/mips/include/asm/cmpxchg.h | 4 ++--
arch/openrisc/include/asm/cmpxchg.h | 4 ++--
arch/parisc/include/asm/cmpxchg.h | 4 ++--
arch/powerpc/include/asm/cmpxchg.h | 4 ++--
arch/riscv/include/asm/atomic.h | 2 +-
arch/riscv/include/asm/cmpxchg.h | 4 ++--
arch/s390/include/asm/cmpxchg.h | 4 ++--
arch/sh/include/asm/cmpxchg.h | 4 ++--
arch/sparc/include/asm/cmpxchg_32.h | 4 ++--
arch/sparc/include/asm/cmpxchg_64.h | 4 ++--
arch/xtensa/include/asm/cmpxchg.h | 4 ++--
drivers/gpu/drm/i915/gt/intel_engine_cs.c | 2 +-
.../gpu/drm/i915/gt/intel_engine_heartbeat.c | 4 ++--
.../drm/i915/gt/intel_execlists_submission.c | 4 ++--
drivers/gpu/drm/i915/gt/intel_ggtt.c | 4 ++--
drivers/gpu/drm/i915/gt/intel_gsc.c | 2 +-
drivers/gpu/drm/i915/gt/intel_gt.c | 4 ++--
drivers/gpu/drm/i915/gt/intel_gt_pm.c | 2 +-
drivers/gpu/drm/i915/gt/intel_lrc.c | 6 +++---
drivers/gpu/drm/i915/gt/intel_migrate.c | 2 +-
drivers/gpu/drm/i915/gt/intel_rc6.c | 2 +-
drivers/gpu/drm/i915/gt/intel_rps.c | 2 +-
drivers/gpu/drm/i915/gt/selftest_context.c | 2 +-
.../drm/i915/gt/selftest_ring_submission.c | 2 +-
drivers/gpu/drm/i915/gt/selftest_timeline.c | 2 +-
drivers/gpu/drm/i915/gt/uc/intel_gsc_uc.c | 2 +-
drivers/gpu/drm/i915/gt/uc/intel_uc.c | 2 +-
drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c | 2 +-
drivers/gpu/drm/i915/i915_utils.h | 1 +
include/linux/non-atomic/xchg.h | 19 +++++++++++++++++++
39 files changed, 84 insertions(+), 64 deletions(-)
create mode 100644 include/linux/non-atomic/xchg.h
--
2.34.1
next reply other threads:[~2022-12-22 11:46 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-22 11:46 Andrzej Hajda [this message]
2022-12-22 11:46 ` [PATCH 01/19] arch/alpha: rename internal name __xchg to __arch_xchg Andrzej Hajda
2022-12-22 11:46 ` [PATCH 02/19] arch/arc: " Andrzej Hajda
2022-12-29 9:32 ` Arnd Bergmann
2022-12-29 11:33 ` [PATCH v2] arch: rename all internal names " Andrzej Hajda
2022-12-29 23:00 ` kernel test robot
2022-12-30 14:15 ` [PATCH v3] " Andrzej Hajda
2023-01-03 10:02 ` Heiko Carstens
2023-01-05 9:54 ` [PATCH v4] " Andrzej Hajda
2023-01-16 10:00 ` Geert Uytterhoeven
2023-01-16 10:00 ` Geert Uytterhoeven
2023-01-02 8:30 ` [PATCH v2] " Geert Uytterhoeven
2022-12-22 11:46 ` [PATCH 03/19] arch/arm: rename internal name " Andrzej Hajda
2022-12-22 11:46 ` [PATCH 04/19] arch/arm64: " Andrzej Hajda
2022-12-22 11:46 ` [PATCH 05/19] arch/hexagon: " Andrzej Hajda
2022-12-22 11:46 ` [PATCH 06/19] arch/ia64: " Andrzej Hajda
2022-12-22 11:46 ` [PATCH 07/19] arch/loongarch: " Andrzej Hajda
2022-12-22 11:46 ` [PATCH 08/19] arch/m68k: " Andrzej Hajda
2022-12-22 11:46 ` [PATCH 09/19] arch/mips: " Andrzej Hajda
2022-12-22 11:46 ` [PATCH 10/19] arch/openrisc: " Andrzej Hajda
2022-12-22 11:46 ` [PATCH 11/19] arch/parisc: " Andrzej Hajda
2022-12-22 11:46 ` [PATCH 12/19] arch/powerpc: correct logged function names in xchg helpers Andrzej Hajda
2022-12-22 11:46 ` [PATCH 13/19] arch/riscv: rename internal name __xchg to __arch_xchg Andrzej Hajda
2022-12-29 16:22 ` Palmer Dabbelt
2023-02-15 5:22 ` Palmer Dabbelt
2022-12-22 11:46 ` [PATCH 14/19] arch/s390: " Andrzej Hajda
2022-12-22 11:46 ` [PATCH 15/19] arch/sh: " Andrzej Hajda
2022-12-22 11:46 ` [PATCH 16/19] arch/sparc: " Andrzej Hajda
2022-12-22 11:46 ` [PATCH 17/19] arch/xtensa: " Andrzej Hajda
2022-12-22 11:46 ` [PATCH 18/19] linux/include: add non-atomic version of xchg Andrzej Hajda
2022-12-22 12:47 ` Andy Shevchenko
2022-12-22 11:46 ` [PATCH 19/19] drm/i915/gt: use __xchg instead of internal helper Andrzej Hajda
2022-12-22 14:12 ` [PATCH 00/19] Introduce __xchg, non-atomic xchg Geert Uytterhoeven
2022-12-22 14:17 ` Andrzej Hajda
2022-12-22 17:21 ` Andrew Morton
2022-12-23 14:23 ` Alexander Lobakin
2022-12-29 9:54 ` Andrzej Hajda
2023-01-05 16:29 ` Daniel Vetter
2023-01-10 10:53 ` [RFC DO NOT MERGE] treewide: use __xchg in most obvious places Andrzej Hajda
2023-01-10 11:07 ` Andy Shevchenko
2023-01-10 12:46 ` [Intel-gfx] " Andrzej Hajda
2023-01-10 13:52 ` Andy Shevchenko
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