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[PW_SID:1119990] futex: Optimise the size check get_futex_key()#2195

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[PW_SID:1119990] futex: Optimise the size check get_futex_key()#2195
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@linux-riscv-bot linux-riscv-bot commented Jul 1, 2026

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PR for series 1119990 applied to workflow__riscv__fixes

Name: futex: Optimise the size check get_futex_key()
URL: https://patchwork.kernel.org/project/linux-riscv/list/?series=1119990
Version: 1

Linux RISC-V bot and others added 2 commits July 1, 2026 03:48
Adding CI files
89be0ce
futex: Optimise the size check get_futex_key()
59c8ee5 
The futex address must be naturally aligned and this is checked via
"address % size" where `address' is the supplied address and `size' is
the expected size of futex. It is guaranteed that `size' is power of two
but the compiler does not see it and creates here a `div' operation
(x86, arm, gcc-15).

We can take advantage of the pow2 property and rewrite it as
"address & (size-1)".

As per testing, the command
|perf bench futex hash -f 1 -b 16384 -t 1 -r 30

improved from
| [thread  0] futex: 0x5619f931f740 [ 7001583 ops/sec ]
to
| [thread  0] futex: 0x55da173e5740 [ 7376137 ops/sec ]

or by 5.3%

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>
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linux-riscv-bot commented Jul 1, 2026

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Patch 1: "futex: Optimise the size check get_futex_key()"
build-rv32-defconfig
Desc: Builds riscv32 defconfig
Duration: 120.99 seconds
Result: PASS

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linux-riscv-bot commented Jul 1, 2026

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Patch 1: "futex: Optimise the size check get_futex_key()"
build-rv64-clang-allmodconfig
Desc: Builds riscv64 allmodconfig with Clang, and checks for errors and added warnings
Duration: 1415.79 seconds
Result: PASS

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linux-riscv-bot commented Jul 1, 2026

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Patch 1: "futex: Optimise the size check get_futex_key()"
build-rv64-gcc-allmodconfig
Desc: Builds riscv64 allmodconfig with GCC, and checks for errors and added warnings
Duration: 1696.67 seconds
Result: PASS

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linux-riscv-bot commented Jul 1, 2026

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Patch 1: "futex: Optimise the size check get_futex_key()"
build-rv64-nommu-k210-defconfig
Desc: Builds riscv64 defconfig with NOMMU for K210
Duration: 21.40 seconds
Result: PASS

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linux-riscv-bot commented Jul 1, 2026

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Patch 1: "futex: Optimise the size check get_futex_key()"
build-rv64-nommu-k210-virt
Desc: Builds riscv64 defconfig with NOMMU for the virt platform
Duration: 23.55 seconds
Result: PASS

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linux-riscv-bot commented Jul 1, 2026

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Patch 1: "futex: Optimise the size check get_futex_key()"
checkpatch
Desc: Runs checkpatch.pl on the patch
Duration: 1.54 seconds
Result: WARNING
Output:

CHECK: spaces preferred around that '-' (ctx:VxV)
#40: FILE: kernel/futex/core.c:523:
+	if (unlikely((address & (size-1)) != 0))
 	                             ^

total: 0 errors, 0 warnings, 1 checks, 8 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

Commit 59c8ee54d09c ("futex: Optimise the size check get_futex_key()") has style problems, please review.

NOTE: Ignored message types: ALLOC_SIZEOF_STRUCT CAMELCASE COMMIT_LOG_LONG_LINE GIT_COMMIT_ID MACRO_ARG_REUSE NO_AUTHOR_SIGN_OFF

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.
total: 0 errors, 0 warnings, 1 checks, 8 lines checked
CHECK: spaces preferred around that '-' (ctx:VxV)

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linux-riscv-bot commented Jul 1, 2026

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Patch 1: "futex: Optimise the size check get_futex_key()"
dtb-warn-rv64
Desc: Checks for Device Tree warnings/errors
Duration: 79.08 seconds
Result: PASS

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linux-riscv-bot commented Jul 1, 2026

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Patch 1: "futex: Optimise the size check get_futex_key()"
header-inline
Desc: Detects static functions without inline keyword in header files
Duration: 0.23 seconds
Result: PASS

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linux-riscv-bot commented Jul 1, 2026

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Patch 1: "futex: Optimise the size check get_futex_key()"
kdoc
Desc: Detects for kdoc errors
Duration: 1.20 seconds
Result: PASS

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linux-riscv-bot commented Jul 1, 2026

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Patch 1: "futex: Optimise the size check get_futex_key()"
module-param
Desc: Detect module_param changes
Duration: 0.24 seconds
Result: PASS

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linux-riscv-bot commented Jul 1, 2026

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Patch 1: "futex: Optimise the size check get_futex_key()"
verify-fixes
Desc: Verifies that the Fixes: tags exist
Duration: 0.22 seconds
Result: PASS

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linux-riscv-bot commented Jul 1, 2026

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Patch 1: "futex: Optimise the size check get_futex_key()"
verify-signedoff
Desc: Verifies that Signed-off-by: tags are correct
Duration: 0.26 seconds
Result: PASS

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linux-riscv-bot force-pushed the workflow__riscv__fixes branch 3 times, most recently from a50938c to 40ba5ca Compare July 8, 2026 17:32
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linux-riscv-bot deleted the pw1119990 branch July 9, 2026 04:38
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