Messages in this thread | | | Date | Wed, 28 Feb 2018 09:03:19 +0900 | From | Minchan Kim <> | Subject | Re: [PATCH] mm/zsmalloc: strength reduce zspage_size calculation |
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Hi Joey,
On Mon, Feb 26, 2018 at 02:21:26AM -1000, Joey Pabalinas wrote: > Replace the repeated multiplication in the main loop > body calculation of zspage_size with an equivalent > (and cheaper) addition operation. > > Signed-off-by: Joey Pabalinas <joeypabalinas@gmail.com> > > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > index c3013505c30527dc42..647a1a2728634b5194 100644 > --- a/mm/zsmalloc.c > +++ b/mm/zsmalloc.c > @@ -821,15 +821,15 @@ static enum fullness_group fix_fullness_group(struct size_class *class, > */ > static int get_pages_per_zspage(int class_size) > { > + int zspage_size = 0; > int i, max_usedpc = 0; > /* zspage order which gives maximum used size per KB */ > int max_usedpc_order = 1; > > for (i = 1; i <= ZS_MAX_PAGES_PER_ZSPAGE; i++) { > - int zspage_size; > int waste, usedpc; > > - zspage_size = i * PAGE_SIZE; > + zspage_size += PAGE_SIZE; > waste = zspage_size % class_size; > usedpc = (zspage_size - waste) * 100 / zspage_size; >
Thanks for the patch! However, it's used only zs_create_pool which is really cold path so I don't feel it would improve for real practice.
Thanks.
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