| Message ID | 20210120071508.9078-1-linmiaohe@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] hugetlbfs: remove meaningless variable avoid_reserve | expand |
On 1/19/21 11:15 PM, Miaohe Lin wrote: > The variable avoid_reserve is meaningless because we never changed its > value and just passed it to alloc_huge_page(). So remove it to make code > more clear that in hugetlbfs_fallocate, we never avoid reserve when alloc > hugepage yet. Also add a comment offered by Mike Kravetz to explain this. > > Reviewed-by: David Hildenbrand <david@redhat.com> > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> > Cc: Mike Kravetz <mike.kravetz@oracle.com> > --- > fs/hugetlbfs/inode.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> > > diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c > index 4bbfd78a7ccb..14df2f73b8ef 100644 > --- a/fs/hugetlbfs/inode.c > +++ b/fs/hugetlbfs/inode.c > @@ -680,7 +680,6 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset, > */ > struct page *page; > unsigned long addr; > - int avoid_reserve = 0; > > cond_resched(); > > @@ -716,8 +715,15 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset, > continue; > } > > - /* Allocate page and add to page cache */ > - page = alloc_huge_page(&pseudo_vma, addr, avoid_reserve); > + /* > + * Allocate page without setting the avoid_reserve argument. > + * There certainly are no reserves associated with the > + * pseudo_vma. However, there could be shared mappings with > + * reserves for the file at the inode level. If we fallocate > + * pages in these areas, we need to consume the reserves > + * to keep reservation accounting consistent. > + */ > + page = alloc_huge_page(&pseudo_vma, addr, 0); > hugetlb_drop_vma_policy(&pseudo_vma); > if (IS_ERR(page)) { > mutex_unlock(&hugetlb_fault_mutex_table[hash]); >
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 4bbfd78a7ccb..14df2f73b8ef 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -680,7 +680,6 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset, */ struct page *page; unsigned long addr; - int avoid_reserve = 0; cond_resched(); @@ -716,8 +715,15 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset, continue; } - /* Allocate page and add to page cache */ - page = alloc_huge_page(&pseudo_vma, addr, avoid_reserve); + /* + * Allocate page without setting the avoid_reserve argument. + * There certainly are no reserves associated with the + * pseudo_vma. However, there could be shared mappings with + * reserves for the file at the inode level. If we fallocate + * pages in these areas, we need to consume the reserves + * to keep reservation accounting consistent. + */ + page = alloc_huge_page(&pseudo_vma, addr, 0); hugetlb_drop_vma_policy(&pseudo_vma); if (IS_ERR(page)) { mutex_unlock(&hugetlb_fault_mutex_table[hash]);