linux-kernel - [PATCH] mm: shmem: add large folio support for tmpfs fix

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Message-Id: <dfa8356b04fb2c9dfd908a7bbb353b942b0b113c.1731477422.git.baolin.wang@linux.alibaba.com>
Date: Wed, 13 Nov 2024 14:53:28 +0800
From: Baolin Wang <baolin.wang@...ux.alibaba.com>
To: baolin.wang@...ux.alibaba.com
Cc: 21cnbao@...il.com,
	akpm@...ux-foundation.org,
	da.gomez@...sung.com,
	david@...hat.com,
	hughd@...gle.com,
	ioworker0@...il.com,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org,
	ryan.roberts@....com,
	wangkefeng.wang@...wei.com,
	willy@...radead.org
Subject: [PATCH] mm: shmem: add large folio support for tmpfs fix

As David suggested: "We can allow all orders up to MAX_PAGECACHE_ORDER,
since shmem_mapping_size_orders() handles it properly", therefore we can
drop the 'MAX_PAGECACHE_ORDER' condition.

Signed-off-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
---
 mm/shmem.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index a3203cf8860f..d54b24d65193 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -590,19 +590,19 @@ static unsigned int shmem_huge_global_enabled(struct inode *inode, pgoff_t index
 					      struct vm_area_struct *vma,
 					      unsigned long vm_flags)
 {
+	unsigned int maybe_pmd_order = HPAGE_PMD_ORDER > MAX_PAGECACHE_ORDER ?
+		0 : BIT(HPAGE_PMD_ORDER);
 	unsigned long within_size_orders;
 	unsigned int order;
 	pgoff_t aligned_index;
 	loff_t i_size;
 
-	if (HPAGE_PMD_ORDER > MAX_PAGECACHE_ORDER)
-		return 0;
 	if (!S_ISREG(inode->i_mode))
 		return 0;
 	if (shmem_huge == SHMEM_HUGE_DENY)
 		return 0;
 	if (shmem_huge_force || shmem_huge == SHMEM_HUGE_FORCE)
-		return BIT(HPAGE_PMD_ORDER);
+		return maybe_pmd_order;
 
 	/*
 	 * The huge order allocation for anon shmem is controlled through
@@ -619,12 +619,12 @@ static unsigned int shmem_huge_global_enabled(struct inode *inode, pgoff_t index
 	switch (SHMEM_SB(inode->i_sb)->huge) {
 	case SHMEM_HUGE_ALWAYS:
 		if (vma)
-			return BIT(HPAGE_PMD_ORDER);
+			return maybe_pmd_order;
 
 		return shmem_mapping_size_orders(inode->i_mapping, index, write_end);
 	case SHMEM_HUGE_WITHIN_SIZE:
 		if (vma)
-			within_size_orders = BIT(HPAGE_PMD_ORDER);
+			within_size_orders = maybe_pmd_order;
 		else
 			within_size_orders = shmem_mapping_size_orders(inode->i_mapping,
 								       index, write_end);
@@ -642,7 +642,7 @@ static unsigned int shmem_huge_global_enabled(struct inode *inode, pgoff_t index
 		fallthrough;
 	case SHMEM_HUGE_ADVISE:
 		if (vm_flags & VM_HUGEPAGE)
-			return BIT(HPAGE_PMD_ORDER);
+			return maybe_pmd_order;
 		fallthrough;
 	default:
 		return 0;
-- 
2.39.3