On Mon, Jan 7, 2013 at 12:24 PM, Seth Jennings <sjenning@xxxxxxxxxxxxxxxxxx> wrote: > Right now ZS_SIZE_CLASS_DELTA is hardcoded to be 16. This > creates 254 classes for systems with 4k pages. However, on > PPC64 with 64k pages, it creates 4095 classes which is far > too many. > > This patch makes ZS_SIZE_CLASS_DELTA relative to PAGE_SIZE > so that regardless of the page size, there will be the same > number of classes. > > Signed-off-by: Seth Jennings <sjenning@xxxxxxxxxxxxxxxxxx> > --- > drivers/staging/zsmalloc/zsmalloc-main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/staging/zsmalloc/zsmalloc-main.c b/drivers/staging/zsmalloc/zsmalloc-main.c > index 825e124..3543047 100644 > --- a/drivers/staging/zsmalloc/zsmalloc-main.c > +++ b/drivers/staging/zsmalloc/zsmalloc-main.c > @@ -141,7 +141,7 @@ > * ZS_MIN_ALLOC_SIZE and ZS_SIZE_CLASS_DELTA must be multiple of ZS_ALIGN > * (reason above) > */ > -#define ZS_SIZE_CLASS_DELTA 16 > +#define ZS_SIZE_CLASS_DELTA (PAGE_SIZE >> 8) > #define ZS_SIZE_CLASSES ((ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE) / \ > ZS_SIZE_CLASS_DELTA + 1) > Actually, there is no point creating size classes beyond [M/(M+1)] * PAGE_SIZE where M is the maximum number of system pages in a zspage. All size classes beyond this size can be collapsed with PAGE_SIZE size class. This can significantly reduce number of size classes created but I think changes needed to do this would be more involved, so perhaps, should be done in another patch. Can you please resend part of this series (patch 1 to patch 4) which deals just with zsmalloc separately? I haven't yet looked into zswap itself so would help with zsmalloc bits are separated out. Acked-by: Nitin Gupta <ngupta@xxxxxxxxxx> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>