mm, THP: clean up return value of madvise_free_huge_pmd

The definition of return value of madvise_free_huge_pmd is not clear
before.  According to the suggestion of Minchan Kim, change the type of
return value to bool and return true if we do MADV_FREE successfully on
entire pmd page, otherwise, return false.  Comments are added too.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: "Huang, Ying" <[email protected]>
Acked-by: Minchan Kim <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Jerome Marchand <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Ebru Akagunduz <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 92ce91c03cd0e0165279c01e90e58f1f271f8a4b..6f14de45b5ce0807e01f7c5093d46ab5c9a546bb 100644 (file)
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -11,7 +11,7 @@ extern struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
                                          unsigned long addr,
                                          pmd_t *pmd,
                                          unsigned int flags);
-extern int madvise_free_huge_pmd(struct mmu_gather *tlb,
+extern bool madvise_free_huge_pmd(struct mmu_gather *tlb,
                        struct vm_area_struct *vma,
                        pmd_t *pmd, unsigned long addr, unsigned long next);
 extern int zap_huge_pmd(struct mmu_gather *tlb,

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 121a7f808216fbc157b8b069099935b05b62aa9d..8f0cd35345dc78ee25d26e4bede40d6f55b72f1f 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1249,25 +1249,26 @@ out:
        return 0;
 }
 
-int madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
+/*
+ * Return true if we do MADV_FREE successfully on entire pmd page.
+ * Otherwise, return false.
+ */
+bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
                pmd_t *pmd, unsigned long addr, unsigned long next)
-
 {
        spinlock_t *ptl;
        pmd_t orig_pmd;
        struct page *page;
        struct mm_struct *mm = tlb->mm;
-       int ret = 0;
+       bool ret = false;
 
        ptl = pmd_trans_huge_lock(pmd, vma);
        if (!ptl)
                goto out_unlocked;
 
        orig_pmd = *pmd;
-       if (is_huge_zero_pmd(orig_pmd)) {
-               ret = 1;
+       if (is_huge_zero_pmd(orig_pmd))
                goto out;
-       }
 
        page = pmd_page(orig_pmd);
        /*
@@ -1309,7 +1310,7 @@ int madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
                set_pmd_at(mm, addr, pmd, orig_pmd);
                tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
        }
-       ret = 1;
+       ret = true;
 out:
        spin_unlock(ptl);
 out_unlocked: