path: root/arch/s390/include/asm/trace
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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2015-08-20 12:57:33 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2015-10-14 14:32:06 +0200
commitacdc9fc9a8121ce2ebcd7533bd72852c20b353f3 (patch)
treeb1d501fa146502365256a02ac6aa3352ced890fa /arch/s390/include/asm/trace
parent5614dd920a02a524c9abc9573374d81f0535f18a (diff)
s390/bitops: implement cache friendly test_and_set_bit_lock
The generic implementation for test_and_set_bit_lock in include/asm-generic uses the standard test_and_set_bit operation. This is done with either a 'csg' or a 'loag' instruction. For both version the cache line is fetched exclusively, even if the bit is already set. The result is an increase in cache traffic, for a contented lock this is a bad idea. Acked-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include/asm/trace')
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