Messages in this thread | | | Date | Sun, 18 Nov 2018 17:03:00 -0800 | From | Matthew Wilcox <> | Subject | Re: [PATCH] mm/filemap.c: minor optimization in write_iter file operation |
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On Sun, Nov 18, 2018 at 11:02:19PM +0800, Yafang Shao wrote: > On Sun, Nov 18, 2018 at 8:13 PM Matthew Wilcox <willy@infradead.org> wrote: > > Did you check the before/after code generation with this patch applied? > > Yes, I did. > My oompiler is gcc-4.8.5, a litte old, and with CONFIG_CC_OPTIMIZE_FOR_SIZE on. > > with gcc 8.2.0, I see no difference, indicating that the compiler already > > makes this optimisation. > > Could pls. try set CONFIG_CC_OPTIMIZE_FOR_SIZE on and then compare them again ?
Actually it was already on:
# CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE is not set CONFIG_CC_OPTIMIZE_FOR_SIZE=y
I happened to build it in my build-tiny output tree.
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