The patch titled
Subject: mm: shmem: simplify the suitable huge orders validation for tmpfs
has been added to the -mm mm-unstable branch. Its filename is
mm-shmem-simplify-the-suitable-huge-orders-validation-for-tmpfs.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-shmem-simplify-the-suitable-huge-orders-validation-for-tmpfs.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Subject: mm: shmem: simplify the suitable huge orders validation for tmpfs
Date: Mon, 22 Jul 2024 13:43:17 +0800
Patch series "Some cleanups for shmem", v3.
This series does some cleanups to reuse code, rename functions and
simplify logic to make code more clear. No functional changes are
expected.
This patch (of 3):
Move the suitable huge orders validation into shmem_suitable_orders() for
tmpfs, which can reuse some code to simplify the logic.
In addition, we don't have special handling for the error code -E2BIG when
checking for conflicts with PMD sized THP in the pagecache for tmpfs,
instead, it will just fallback to order-0 allocations like this patch
does, so this simplification will not add functional changes.
Link: https://lkml.kernel.org/r/cover.1721626645.git.baolin.wang@xxxxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/965985dd6d322929d78a0beee0dafa1c2a1b81e2.1721626645.git.baolin.wang@xxxxxxxxxxxxxxxxx
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Reviewed-by: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Barry Song <21cnbao@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Lance Yang <ioworker0@xxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/shmem.c | 39 +++++++++++++++------------------------
1 file changed, 15 insertions(+), 24 deletions(-)
--- a/mm/shmem.c~mm-shmem-simplify-the-suitable-huge-orders-validation-for-tmpfs
+++ a/mm/shmem.c
@@ -1685,19 +1685,29 @@ static unsigned long shmem_suitable_orde
struct address_space *mapping, pgoff_t index,
unsigned long orders)
{
- struct vm_area_struct *vma = vmf->vma;
+ struct vm_area_struct *vma = vmf ? vmf->vma : NULL;
unsigned long pages;
int order;
- orders = thp_vma_suitable_orders(vma, vmf->address, orders);
- if (!orders)
- return 0;
+ if (vma) {
+ orders = thp_vma_suitable_orders(vma, vmf->address, orders);
+ if (!orders)
+ return 0;
+ }
/* Find the highest order that can add into the page cache */
order = highest_order(orders);
while (orders) {
pages = 1UL << order;
index = round_down(index, pages);
+ /*
+ * Check for conflict before waiting on a huge allocation.
+ * Conflict might be that a huge page has just been allocated
+ * and added to page cache by a racing thread, or that there
+ * is already at least one small page in the huge extent.
+ * Be careful to retry when appropriate, but not forever!
+ * Elsewhere -EEXIST would be the right code, but not here.
+ */
if (!xa_find(&mapping->i_pages, &index,
index + pages - 1, XA_PRESENT))
break;
@@ -1735,7 +1745,6 @@ static struct folio *shmem_alloc_and_add
{
struct address_space *mapping = inode->i_mapping;
struct shmem_inode_info *info = SHMEM_I(inode);
- struct vm_area_struct *vma = vmf ? vmf->vma : NULL;
unsigned long suitable_orders = 0;
struct folio *folio = NULL;
long pages;
@@ -1745,26 +1754,8 @@ static struct folio *shmem_alloc_and_add
orders = 0;
if (orders > 0) {
- if (vma && vma_is_anon_shmem(vma)) {
- suitable_orders = shmem_suitable_orders(inode, vmf,
+ suitable_orders = shmem_suitable_orders(inode, vmf,
mapping, index, orders);
- } else if (orders & BIT(HPAGE_PMD_ORDER)) {
- pages = HPAGE_PMD_NR;
- suitable_orders = BIT(HPAGE_PMD_ORDER);
- index = round_down(index, HPAGE_PMD_NR);
-
- /*
- * Check for conflict before waiting on a huge allocation.
- * Conflict might be that a huge page has just been allocated
- * and added to page cache by a racing thread, or that there
- * is already at least one small page in the huge extent.
- * Be careful to retry when appropriate, but not forever!
- * Elsewhere -EEXIST would be the right code, but not here.
- */
- if (xa_find(&mapping->i_pages, &index,
- index + HPAGE_PMD_NR - 1, XA_PRESENT))
- return ERR_PTR(-E2BIG);
- }
order = highest_order(suitable_orders);
while (suitable_orders) {
_
Patches currently in -mm which might be from baolin.wang@xxxxxxxxxxxxxxxxx are
mm-shmem-simplify-the-suitable-huge-orders-validation-for-tmpfs.patch
mm-shmem-rename-shmem_is_huge-to-shmem_huge_global_enabled.patch
mm-shmem-move-shmem_huge_global_enabled-into-shmem_allowable_huge_orders.patch
