| Message ID | 20210410072348.20437-4-linmiaohe@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Cleanup and fixup for hugetlb | expand |
On 4/10/21 12:23 AM, Miaohe Lin wrote: > The resv_map could be NULL since this routine can be called in the evict > inode path for all hugetlbfs inodes and we will have chg = 0 in this case. > But (chg - freed) won't go negative as Mike pointed out: > > "If resv_map is NULL, then no hugetlb pages can be allocated/associated > with the file. As a result, remove_inode_hugepages will never find any > huge pages associated with the inode and the passed value 'freed' will > always be zero." > > Add a comment clarifying this to make it clear and also avoid confusion. > > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Thanks, Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 9b4c05699a90..387c9a62615e 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5435,6 +5435,9 @@ long hugetlb_unreserve_pages(struct inode *inode, long start, long end, /* * If the subpool has a minimum size, the number of global * reservations to be released may be adjusted. + * + * Note that !resv_map implies freed == 0. So (chg - freed) + * won't go negative. */ gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed)); hugetlb_acct_memory(h, -gbl_reserve);
The resv_map could be NULL since this routine can be called in the evict inode path for all hugetlbfs inodes and we will have chg = 0 in this case. But (chg - freed) won't go negative as Mike pointed out: "If resv_map is NULL, then no hugetlb pages can be allocated/associated with the file. As a result, remove_inode_hugepages will never find any huge pages associated with the inode and the passed value 'freed' will always be zero." Add a comment clarifying this to make it clear and also avoid confusion. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> --- mm/hugetlb.c | 3 +++ 1 file changed, 3 insertions(+)