From: Oscar Salvador <osalvador@xxxxxxx> Subject: mm: fix comment for NODEMASK_ALLOC Currently, NODEMASK_ALLOC allocates a nodemask_t with kmalloc when NODES_SHIFT is higher than 8, otherwise it declares it within the stack. The comment says that the reasoning behind this, is that nodemask_t will be 256 bytes when NODES_SHIFT is higher than 8, but this is not true. For example, NODES_SHIFT = 9 will give us a 64 bytes nodemask_t. Let us fix up the comment for that. Another thing is that it might make sense to let values lower than 128bytes be allocated in the stack. Although this all depends on the depth of the stack (and this changes from function to function), I think that 64 bytes is something we can easily afford. So we could even bump the limit by 1 (from > 8 to > 9). Link: http://lkml.kernel.org/r/20180820085516.9687-1-osalvador@xxxxxxxxxxxxxxxxxx Signed-off-by: Oscar Salvador <osalvador@xxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/nodemask.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/linux/nodemask.h~mm-fix-comment-for-nodemask_alloc +++ a/include/linux/nodemask.h @@ -518,7 +518,7 @@ static inline int node_random(const node * NODEMASK_ALLOC(type, name) allocates an object with a specified type and * name. */ -#if NODES_SHIFT > 8 /* nodemask_t > 256 bytes */ +#if NODES_SHIFT > 8 /* nodemask_t > 32 bytes */ #define NODEMASK_ALLOC(type, name, gfp_flags) \ type *name = kmalloc(sizeof(*name), gfp_flags) #define NODEMASK_FREE(m) kfree(m) _
