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| author | Alexey Dobriyan <adobriyan@gmail.com> | 2019-03-05 15:44:18 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-03-05 21:07:16 -0800 |
| commit | d71e53cee7c2e553b85c572e76da778a93d32135 (patch) | |
| tree | 95a190ac9ba693dce12265cad873a7309dd8af36 /mm/filemap.c | |
| parent | e9f598730ea0dde3b45560766240503367c404b7 (diff) | |
| download | lwn-d71e53cee7c2e553b85c572e76da778a93d32135.tar.gz lwn-d71e53cee7c2e553b85c572e76da778a93d32135.zip | |
mm: shuffle GFP_* flags
GFP_KERNEL is one of the most used constant but on archs like arm with
fixed length instruction some constants are more equal than the others.
Constants with tightly packed bits can be injected directly into
instruction stream:
0: e3a00d33 mov r0, #3264 ; 0xcc0
Others require multiple instructions or even loading out of instruction
stream:
0: e3a000c0 mov r0, #192 ; 0xc0
4: e3400060 movt r0, #96 ; 0x60
Shuffle GFP_* flags so that GFP_KERNEL/GFP_ATOMIC + __GFP_ZERO bits are
close to each other.
Savings on arm configs are ~0.1%.
Link: http://lkml.kernel.org/r/20190109201838.GA9140@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/filemap.c')
0 files changed, 0 insertions, 0 deletions