Re: [PATCH 2/4] hugetlg: Break earlier in add_reservation_in_range() when we can
From: Miaohe Lin <linmiaohe@huawei.com>
Date: 2021-02-04 02:21:13
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Hi: On 2021/2/4 5:08, Peter Xu wrote:
All the regions maintained in hugetlb reserved map is inclusive on "from" but exclusive on "to". We can break earlier even if rg->from==t because it already means no possible intersection. This does not need a Fixes in all cases because when it happens (rg->from==t) we'll not break out of the loop while we should, however the next thing we'd do is still add the last file_region we'd need and quit the loop in the next round. So this change is not a bugfix (since the old code should still run okay iiuc), but we'd better still touch it up to make it logically sane.
I think the difference is when we handle the rg->from == t case. Previous one is in the loop, now below the loop. But the result should be same. Thanks. Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
quoted hunk ↗ jump to hunk
Signed-off-by: Peter Xu <peterx@redhat.com> --- mm/hugetlb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/mm/hugetlb.c b/mm/hugetlb.c index d2859c2aecc9..9e6ea96bf33b 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c@@ -377,7 +377,7 @@ static long add_reservation_in_range(struct resv_map *resv, long f, long t, /* When we find a region that starts beyond our range, we've * finished. */ - if (rg->from > t) + if (rg->from >= t) break; /* Add an entry for last_accounted_offset -> rg->from, and