mm/hugetlb: add available_huge_pages() func

In hugetlb.c there are several places which compare the values of
'h->free_huge_pages' and 'h->resv_huge_pages', it looks a bit messy, so
add a new available_huge_pages() function to do these.

Link: https://lkml.kernel.org/r/20220922021929.98961-1-xhao@linux.alibaba.com
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 3c1316ad54b5f67651491d60882cf72c70c24947..8de5a6b5a172a843c1042e96811d566601658aad 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1191,6 +1191,11 @@ retry_cpuset:
        return NULL;
 }
 
+static unsigned long available_huge_pages(struct hstate *h)
+{
+       return h->free_huge_pages - h->resv_huge_pages;
+}
+
 static struct page *dequeue_huge_page_vma(struct hstate *h,
                                struct vm_area_struct *vma,
                                unsigned long address, int avoid_reserve,
@@ -1207,12 +1212,11 @@ static struct page *dequeue_huge_page_vma(struct hstate *h,
         * have no page reserves. This check ensures that reservations are
         * not "stolen". The child may still get SIGKILLed
         */
-       if (!vma_has_reserves(vma, chg) &&
-                       h->free_huge_pages - h->resv_huge_pages == 0)
+       if (!vma_has_reserves(vma, chg) && !available_huge_pages(h))
                goto err;
 
        /* 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 (avoid_reserve && !available_huge_pages(h))
                goto err;
 
        gfp_mask = htlb_alloc_mask(h);
@@ -2124,7 +2128,7 @@ retry:
        if (!page_count(page)) {
                struct page *head = compound_head(page);
                struct hstate *h = page_hstate(head);
-               if (h->free_huge_pages - h->resv_huge_pages == 0)
+               if (!available_huge_pages(h))
                        goto out;
 
                /*
@@ -2311,7 +2315,7 @@ struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
                nodemask_t *nmask, gfp_t gfp_mask)
 {
        spin_lock_irq(&hugetlb_lock);
-       if (h->free_huge_pages - h->resv_huge_pages > 0) {
+       if (available_huge_pages(h)) {
                struct page *page;
 
                page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);