Messages in this thread | | | Date | Thu, 21 Feb 2013 16:21:37 -0600 | From | Seth Jennings <> | Subject | Re: [PATCHv6 1/8] zsmalloc: add to mm/ |
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On 02/21/2013 02:36 PM, Cody P Schafer wrote: > On Wed, Feb 20, 2013 at 04:04:41PM -0600, Seth Jennings wrote: >> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c >> +#define MAX(a, b) ((a) >= (b) ? (a) : (b)) >> +/* ZS_MIN_ALLOC_SIZE must be multiple of ZS_ALIGN */ >> +#define ZS_MIN_ALLOC_SIZE \ >> + MAX(32, (ZS_MAX_PAGES_PER_ZSPAGE << PAGE_SHIFT >> OBJ_INDEX_BITS)) > > Could you use the max(a,b) defined in include/linux/kernel.h? >
Andrew Morton made the same point. We can't use max() or max_t() because the value of ZS_MIN_ALLOC_SIZE is used to derive the value of ZS_SIZE_CLASSES which is used to size an array in struct zs_pool.
So the expression must be completely evaluated to a number by the precompiler.
Thanks, Seth
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