Messages in this thread | | | Date | Thu, 06 Jan 2011 14:45:13 -0600 | From | Christoph Lameter <> | Subject | [cpuops cmpxchg double V2 0/4] this_cpu_cmpxchg_double support |
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This patch series introduces this_cpu_cmpxchg_double().
x86 cpus support cmpxchg16b and cmpxchg8b instuction which are capable of switching two words instead of one during a cmpxchg. Two words allow to swap more state in an atomic instruction.
this_cpu_cmpxchg_double() is used in the slub allocator to avoid interrupt disable/enable in both alloc and free fastpath. this_cpu_cmpxchg_double() works nicely with the per cpu data of the allocator. Using the new operation significantly speeds up the fastpaths.
V1->V2 - Change parameter convention for this_cpu_cmpxchg_double. Specify both percpu variables in same way as the two old and new values. - Do not require a per cpu pointer but a variable to conform to the convention used in other this_cpu_ops.
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