Anton Blanchard e35735b9a5 powerpc: Speed up clear_page by unrolling it ... Unroll clear_page 8 times. A simple microbenchmark which allocates and frees a zeroed page: for (i = 0; i < iterations; i++) { unsigned long p = __get_free_page(GFP_KERNEL | __GFP_ZERO); free_page(p); } improves 20% on POWER8. This assumes cacheline sizes won't grow beyond 512 bytes or page sizes wont drop below 1kB, which is unlikely, but we could add a runtime check during early init if it makes people nervous. Michael found that some versions of gcc produce quite bad code (all multiplies), so we give gcc a hand by using shifts and adds. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>		2014-10-02 16:04:21 +10:00
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asm	powerpc: Speed up clear_page by unrolling it	2014-10-02 16:04:21 +10:00
uapi/asm	powerpc: Wire up sys_seccomp(), sys_getrandom() and sys_memfd_create()	2014-09-09 19:02:47 +10:00