arm64: assembler: add cond_yield macro

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Add a macro cond_yield that branches to a specified label when called if
the TIF_NEED_RESCHED flag is set and decreasing the preempt count would
make the task preemptible again, resulting in a schedule to occur. This
can be used by kernel mode SIMD code that keeps a lot of state in SIMD
registers, which would make chunking the input in order to perform the
cond_resched() check from C code disproportionately costly.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210203113626.220151-2-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

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Ard Biesheuvel 2021-02-03 12:36:18 +01:00 • committed by Will Deacon

parent 5c8fe583cc

commit d13c613f13

1 changed files with 16 additions and 0 deletions

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arch/arm64/include/asm/assembler.h

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