Re: [PATCH v2] mm/hugetlb: avoid unnecessary hugetlb_acct_memory() call
On 1/15/21 1:44 AM, Miaohe Lin wrote: > Hi: > > On 2021/1/15 17:28, Oscar Salvador wrote: >> On Fri, Jan 15, 2021 at 04:20:13AM -0500, Miaohe Lin wrote: >>> When gbl_reserve is 0, hugetlb_acct_memory() will do nothing except holding >>> and releasing hugetlb_lock. We should avoid this unnecessary hugetlb_lock >>> lock/unlock cycle which is happening on 'most' hugetlb munmap operations by >>> check delta against 0 at the beginning of hugetlb_acct_memory. >>> >>> Reviewed-by: David Hildenbrand >>> Signed-off-by: Miaohe Lin >> >> I would avoid mentioning gbl_reserve as not all callers use it, and focus >> on what delta means: >> >> "When reservation accounting remains unchanged..", but anyway: > > Sounds good. Maybe Andrew could kindly do this if this patch is picked up ? Thank you and Andrew. Looks like Andrew updated the commit message and added to his tree. -- Mike Kravetz
Re: [PATCH v2] mm/hugetlb: avoid unnecessary hugetlb_acct_memory() call
Hi: On 2021/1/15 17:28, Oscar Salvador wrote: > On Fri, Jan 15, 2021 at 04:20:13AM -0500, Miaohe Lin wrote: >> When gbl_reserve is 0, hugetlb_acct_memory() will do nothing except holding >> and releasing hugetlb_lock. We should avoid this unnecessary hugetlb_lock >> lock/unlock cycle which is happening on 'most' hugetlb munmap operations by >> check delta against 0 at the beginning of hugetlb_acct_memory. >> >> Reviewed-by: David Hildenbrand >> Signed-off-by: Miaohe Lin > > I would avoid mentioning gbl_reserve as not all callers use it, and focus > on what delta means: > > "When reservation accounting remains unchanged..", but anyway: Sounds good. Maybe Andrew could kindly do this if this patch is picked up ? > > Reviewed-by: Oscar Salvador > > Many thanks for your review.
Re: [PATCH v2] mm/hugetlb: avoid unnecessary hugetlb_acct_memory() call
On Fri, Jan 15, 2021 at 04:20:13AM -0500, Miaohe Lin wrote: > When gbl_reserve is 0, hugetlb_acct_memory() will do nothing except holding > and releasing hugetlb_lock. We should avoid this unnecessary hugetlb_lock > lock/unlock cycle which is happening on 'most' hugetlb munmap operations by > check delta against 0 at the beginning of hugetlb_acct_memory. > > Reviewed-by: David Hildenbrand > Signed-off-by: Miaohe Lin I would avoid mentioning gbl_reserve as not all callers use it, and focus on what delta means: "When reservation accounting remains unchanged..", but anyway: Reviewed-by: Oscar Salvador -- Oscar Salvador SUSE L3
[PATCH v2] mm/hugetlb: avoid unnecessary hugetlb_acct_memory() call
When gbl_reserve is 0, hugetlb_acct_memory() will do nothing except holding
and releasing hugetlb_lock. We should avoid this unnecessary hugetlb_lock
lock/unlock cycle which is happening on 'most' hugetlb munmap operations by
check delta against 0 at the beginning of hugetlb_acct_memory.
Reviewed-by: David Hildenbrand
Signed-off-by: Miaohe Lin
---
mm/hugetlb.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 4f67f6b159c7..da064cb8fd53 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3591,6 +3591,9 @@ static int hugetlb_acct_memory(struct hstate *h, long
delta)
{
int ret = -ENOMEM;
+ if (!delta)
+ return 0;
+
spin_lock(_lock);
/*
* When cpuset is configured, it breaks the strict hugetlb page
--
2.19.1
