On 01/24/2013 06:17 PM, Nitin Gupta wrote: > 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. Agreed. > 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. I agree there could be some optimization here, but those extra classes really aren't doing any harm that I can see. > 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. Working it now. Thanks, Seth -- 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>