[PATCH] hugetlb: cond_resched for set_max_huge_pages and follow_hugetlb_page

[Spencer Baugh <sbaugh@catern.com>]

From: Joern Engel <joern@logfs.org>

~150ms scheduler latency for both observed in the wild.

Signed-off-by: Joern Engel <joern@logfs.org>
Signed-off-by: Spencer Baugh <sbaugh@catern.com>
---
 mm/hugetlb.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index a8c3087..2eb6919 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1836,6 +1836,7 @@ static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
 			ret = alloc_fresh_gigantic_page(h, nodes_allowed);
 		else
 			ret = alloc_fresh_huge_page(h, nodes_allowed);
+		cond_resched();
 		spin_lock(&hugetlb_lock);
 		if (!ret)
 			goto out;
@@ -3521,6 +3522,7 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
 				spin_unlock(ptl);
 			ret = hugetlb_fault(mm, vma, vaddr,
 				(flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
+			cond_resched();
 			if (!(ret & VM_FAULT_ERROR))
 				continue;
 
-- 
2.5.0.rc3

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