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| author | Will Deacon <will.deacon@arm.com> | 2015-05-29 13:31:10 +0100 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2015-07-27 15:28:53 +0100 |
| commit | 0ea366f5e1b6413a6095dce60ea49ae51e468b61 (patch) | |
| tree | fce4fc690edf16784d21a714415a74a8ce53eb2b /arch/arm64/lib | |
| parent | a82e62382fcbbf5c3348e802af73583e0cac39c0 (diff) | |
| download | op-kernel-dev-0ea366f5e1b6413a6095dce60ea49ae51e468b61.zip op-kernel-dev-0ea366f5e1b6413a6095dce60ea49ae51e468b61.tar.gz | |
arm64: atomics: prefetch the destination word for write prior to stxr
The cost of changing a cacheline from shared to exclusive state can be
significant, especially when this is triggered by an exclusive store,
since it may result in having to retry the transaction.
This patch makes use of prfm to prefetch cachelines for write prior to
ldxr/stxr loops when using the ll/sc atomic routines.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/lib')
| -rw-r--r-- | arch/arm64/lib/bitops.S | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/arm64/lib/bitops.S b/arch/arm64/lib/bitops.S index bc18457..43ac736 100644 --- a/arch/arm64/lib/bitops.S +++ b/arch/arm64/lib/bitops.S @@ -31,6 +31,7 @@ ENTRY( \name ) eor w0, w0, w3 // Clear low bits mov x2, #1 add x1, x1, x0, lsr #3 // Get word offset +alt_lse " prfm pstl1strm, [x1]", "nop" lsl x3, x2, x3 // Create mask alt_lse "1: ldxr x2, [x1]", "\lse x3, [x1]" @@ -48,6 +49,7 @@ ENTRY( \name ) eor w0, w0, w3 // Clear low bits mov x2, #1 add x1, x1, x0, lsr #3 // Get word offset +alt_lse " prfm pstl1strm, [x1]", "nop" lsl x4, x2, x3 // Create mask alt_lse "1: ldxr x2, [x1]", "\lse x4, x2, [x1]" |
