On 03/18/2015 04:59 PM, Michal Hocko wrote:
On Wed 18-03-15 16:40:34, Vlastimil Babka wrote:
On 03/18/2015 04:02 PM, Michal Hocko wrote:
On Wed 18-03-15 15:34:50, Vlastimil Babka wrote:
On 03/16/2015 03:08 PM, Michal Hocko wrote:
@@ -1080,6 +1080,7 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long haddr;
unsigned long mmun_start; /* For mmu_notifiers */
unsigned long mmun_end; /* For mmu_notifiers */
+ gfp_t huge_gfp = GFP_TRANSHUGE; /* for allocation and charge */
This value is actually never used. Is it here because the compiler emits a
spurious non-initialized value warning otherwise? It should be easy for it
to prove that setting new_page to something non-null implies initializing
huge_gfp (in the hunk below), and NULL new_page means it doesn't reach the
mem_cgroup_try_charge() call?
No, I haven't tried to workaround the compiler. It just made the code
more obvious to me. I can remove the initialization if you prefer, of
course.
Yeah IMHO it would be better to remove it, if possible. Leaving it has the
(albeit small) chance that future patch will again use the value in the code
before it's determined based on defrag setting.
Wouldn't an uninitialized value be used in such a case?
Yeah, but then you should get a (correct) warning :)
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