Commit 72d8f726 authored by Peter Xu's avatar Peter Xu Committed by Andrew Morton
Browse files

mm/hugetlb: drop vma_has_reserves() 

After the previous cleanup, vma_has_reserves() is mostly an empty helper
except that it says "use reserve count" is inverted meaning from "needs a
global reserve count", which is still true.

To avoid confusions on having two inverted ways to ask the same question,
always use the gbl_chg everywhere, and drop the function.

When at it, rename "chg" to "gbl_chg" in dequeue_hugetlb_folio_vma().  It
might be helpful for readers to see that the "chg" here is the global
reserve count, not the vma resv count.

Link: https://lkml.kernel.org/r/20250107204002.2683356-7-peterx@redhat.com


Signed-off-by: default avatarPeter Xu <peterx@redhat.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 51e1de00

mm/hugetlb.c

+6 −17
Original line number Diff line number Diff line
@@ -1247,16 +1247,6 @@ void clear_vma_resv_huge_pages(struct vm_area_struct *vma) 
	hugetlb_dup_vma_private(vma);

}



/* Returns true if the VMA has associated reserve pages */

static bool vma_has_reserves(long chg)

{

	/*

	 * Now "chg" has all the conditions considered for whether we

	 * should use an existing reservation.

	 */

	return chg == 0;

}



static void enqueue_hugetlb_folio(struct hstate *h, struct folio *folio)

{

	int nid = folio_nid(folio);
@@ -1345,7 +1335,7 @@ static unsigned long available_huge_pages(struct hstate *h) 


static struct folio *dequeue_hugetlb_folio_vma(struct hstate *h,

				struct vm_area_struct *vma,

				unsigned long address, long chg)

				unsigned long address, long gbl_chg)

{

	struct folio *folio = NULL;

	struct mempolicy *mpol;
@@ -1354,11 +1344,10 @@ static struct folio *dequeue_hugetlb_folio_vma(struct hstate *h, 
	int nid;



	/*

	 * 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

	 * gbl_chg==1 means the allocation requires a new page that was not

	 * reserved before.  Making sure there's at least one free page.

	 */

	if (!vma_has_reserves(chg) && !available_huge_pages(h))

	if (gbl_chg && !available_huge_pages(h))

		goto err;



	gfp_mask = htlb_alloc_mask(h);
@@ -1376,7 +1365,7 @@ static struct folio *dequeue_hugetlb_folio_vma(struct hstate *h, 
		folio = dequeue_hugetlb_folio_nodemask(h, gfp_mask,

							nid, nodemask);



	if (folio && vma_has_reserves(chg)) {

	if (folio && !gbl_chg) {

		folio_set_hugetlb_restore_reserve(folio);

		h->resv_huge_pages--;

	}
@@ -3067,7 +3056,7 @@ struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma, 
		if (!folio)

			goto out_uncharge_cgroup;

		spin_lock_irq(&hugetlb_lock);

		if (vma_has_reserves(gbl_chg)) {

		if (!gbl_chg) {

			folio_set_hugetlb_restore_reserve(folio);

			h->resv_huge_pages--;

		}