Messages in this thread | | | Date | Fri, 6 May 2016 12:09:35 +0900 | From | Minchan Kim <> | Subject | Re: [PATCH] mm/zsmalloc: avoid unnecessary iteration in get_pages_per_zspage() |
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On Thu, May 05, 2016 at 07:03:29PM +0900, Sergey Senozhatsky wrote: > On (05/05/16 13:17), Ganesh Mahendran wrote: > > if we find a zspage with usage == 100%, there is no need to > > try other zspages. > > Hello, > > well... we iterate there from 0 to 1<<2, which is not awfully > a lot to break it in the middle, and we do this only when we > initialize a new pool (for every size class). > > the check is > - true 15 times > - false 492 times
Thanks for the data, Sergey!
> > so it _sort of_ feels like this new if-condition doesn't > buy us a lot, and most of the time it just sits there with > no particular gain. let's hear from Minchan. >
I agree with Sergey. First of al, I appreciates your patch, Ganesh! But as Sergey pointed out, I don't see why it improves current zsmalloc. If you want to merge strongly, please convince me with more detail reason.
Thanks.
> -ss > > > Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com> > > Cc: Minchan Kim <minchan@kernel.org> > > Cc: Nitin Gupta <ngupta@vflare.org> > > Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> > > --- > > mm/zsmalloc.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > > index fda7177..310c7b0 100644 > > --- a/mm/zsmalloc.c > > +++ b/mm/zsmalloc.c > > @@ -765,6 +765,9 @@ static int get_pages_per_zspage(int class_size) > > if (usedpc > max_usedpc) { > > max_usedpc = usedpc; > > max_usedpc_order = i; > > + > > + if (max_usedpc == 100) > > + break; > > } > > } > > > > -- > > 1.7.9.5 > >
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