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Subject[PATCH v2 13/20] mm, hugetlb: mm, hugetlb: unify chg and avoid_reserve to use_reserve
Date
Currently, we have two variable to represent whether we can use reserved
page or not, chg and avoid_reserve, respectively. With aggregating these,
we can have more clean code. This makes no functinoal difference.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 22ceb04..8dff972 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -531,8 +531,7 @@ static struct page *dequeue_huge_page_node(struct hstate *h, int nid)

static struct page *dequeue_huge_page_vma(struct hstate *h,
struct vm_area_struct *vma,
- unsigned long address, int avoid_reserve,
- long chg)
+ unsigned long address, bool use_reserve)
{
struct page *page = NULL;
struct mempolicy *mpol;
@@ -546,12 +545,10 @@ static struct page *dequeue_huge_page_vma(struct hstate *h,
* A child process with MAP_PRIVATE mappings created by their parent
* have no page reserves. This check ensures that reservations are
* not "stolen". The child may still get SIGKILLed
+ * Or, when parent process do COW, we cannot use reserved page.
+ * In this case, ensure enough pages are in the pool.
*/
- if (chg && h->free_huge_pages - h->resv_huge_pages == 0)
- return NULL;
-
- /* If reserves cannot be used, ensure enough pages are in the pool */
- if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
+ if (!use_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
return NULL;

retry_cpuset:
@@ -564,9 +561,7 @@ retry_cpuset:
if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask)) {
page = dequeue_huge_page_node(h, zone_to_nid(zone));
if (page) {
- if (avoid_reserve)
- break;
- if (chg)
+ if (!use_reserve)
break;

SetPagePrivate(page);
@@ -1121,6 +1116,7 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma,
struct hstate *h = hstate_vma(vma);
struct page *page;
long chg;
+ bool use_reserve;
int ret, idx;
struct hugetlb_cgroup *h_cg;

@@ -1136,18 +1132,19 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma,
chg = vma_needs_reservation(h, vma, addr);
if (chg < 0)
return ERR_PTR(-ENOMEM);
- if (chg || avoid_reserve)
+ use_reserve = (!chg && !avoid_reserve);
+ if (!use_reserve)
if (hugepage_subpool_get_pages(spool, 1))
return ERR_PTR(-ENOSPC);

ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
if (ret) {
- if (chg || avoid_reserve)
+ if (!use_reserve)
hugepage_subpool_put_pages(spool, 1);
return ERR_PTR(-ENOSPC);
}
spin_lock(&hugetlb_lock);
- page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, chg);
+ page = dequeue_huge_page_vma(h, vma, addr, use_reserve);
if (!page) {
spin_unlock(&hugetlb_lock);
page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
@@ -1155,7 +1152,7 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma,
hugetlb_cgroup_uncharge_cgroup(idx,
pages_per_huge_page(h),
h_cg);
- if (chg || avoid_reserve)
+ if (!use_reserve)
hugepage_subpool_put_pages(spool, 1);
return ERR_PTR(-ENOSPC);
}
--
1.7.9.5


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