linux-kernel - [PATCH] fs: hugetlbfs: Set vma policy only when needed for allocating folio

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Date:   Tue,  2 May 2023 23:56:22 +0000
From:   Ackerley Tng <ackerleytng@...gle.com>
To:     akpm@...ux-foundation.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        mike.kravetz@...cle.com, muchun.song@...ux.dev,
        willy@...radead.org, sidhartha.kumar@...cle.com,
        jhubbard@...dia.com
Cc:     vannapurve@...gle.com, erdemaktas@...gle.com,
        Ackerley Tng <ackerleytng@...gle.com>
Subject: [PATCH] fs: hugetlbfs: Set vma policy only when needed for allocating folio

Calling hugetlb_set_vma_policy() later avoids setting the vma policy
and then dropping it on a page cache hit.

Signed-off-by: Ackerley Tng <ackerleytng@...gle.com>
---
 fs/hugetlbfs/inode.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index f640cff1bbce..380b1cd6c93f 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -833,9 +833,6 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 			break;
 		}
 
-		/* Set numa allocation policy based on index */
-		hugetlb_set_vma_policy(&pseudo_vma, inode, index);
-
 		/* addr is the offset within the file (zero based) */
 		addr = index * hpage_size;
 
@@ -846,7 +843,6 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 		/* See if already present in mapping to avoid alloc/free */
 		if (filemap_has_folio(mapping, index)) {
 			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
-			hugetlb_drop_vma_policy(&pseudo_vma);
 			continue;
 		}
 
@@ -858,6 +854,7 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 		 * folios in these areas, we need to consume the reserves
 		 * to keep reservation accounting consistent.
 		 */
+		hugetlb_set_vma_policy(&pseudo_vma, inode, index);
 		folio = alloc_hugetlb_folio(&pseudo_vma, addr, 0);
 		hugetlb_drop_vma_policy(&pseudo_vma);
 		if (IS_ERR(folio)) {
-- 
2.40.1.495.gc816e09b53d-goog