The patch titled
Subject: mm: hugetlb_vmemmap: move mmap lock to vmemmap_remap_range()
has been added to the -mm mm-unstable branch. Its filename is
mm-hugetlb_vmemmap-move-mmap-lock-to-vmemmap_remap_range.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hugetlb_vmemmap-move-mmap-lock-to-vmemmap_remap_range.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: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Subject: mm: hugetlb_vmemmap: move mmap lock to vmemmap_remap_range()
Date: Tue, 5 Dec 2023 11:08:53 +0800
All the users of vmemmap_remap_range() will hold the mmap lock and release
it once it returns, it is naturally to move the lock to
vmemmap_remap_range() to simplify the code and the users.
Link: https://lkml.kernel.org/r/20231205030853.3921-1-songmuchun@xxxxxxxxxxxxx
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb_vmemmap.c | 17 ++++-------------
1 file changed, 4 insertions(+), 13 deletions(-)
--- a/mm/hugetlb_vmemmap.c~mm-hugetlb_vmemmap-move-mmap-lock-to-vmemmap_remap_range
+++ a/mm/hugetlb_vmemmap.c
@@ -163,8 +163,10 @@ static int vmemmap_remap_range(unsigned
VM_BUG_ON(!PAGE_ALIGNED(start | end));
+ mmap_read_lock(&init_mm);
ret = walk_page_range_novma(&init_mm, start, end, &vmemmap_remap_ops,
NULL, walk);
+ mmap_read_unlock(&init_mm);
if (ret)
return ret;
@@ -282,7 +284,6 @@ static void vmemmap_restore_pte(pte_t *p
static int vmemmap_remap_split(unsigned long start, unsigned long end,
unsigned long reuse)
{
- int ret;
struct vmemmap_remap_walk walk = {
.remap_pte = NULL,
.flags = VMEMMAP_SPLIT_NO_TLB_FLUSH,
@@ -291,11 +292,7 @@ static int vmemmap_remap_split(unsigned
/* See the comment in the vmemmap_remap_free(). */
BUG_ON(start - reuse != PAGE_SIZE);
- mmap_read_lock(&init_mm);
- ret = vmemmap_remap_range(reuse, end, &walk);
- mmap_read_unlock(&init_mm);
-
- return ret;
+ return vmemmap_remap_range(reuse, end, &walk);
}
/**
@@ -358,7 +355,6 @@ static int vmemmap_remap_free(unsigned l
*/
BUG_ON(start - reuse != PAGE_SIZE);
- mmap_read_lock(&init_mm);
ret = vmemmap_remap_range(reuse, end, &walk);
if (ret && walk.nr_walked) {
end = reuse + walk.nr_walked * PAGE_SIZE;
@@ -377,7 +373,6 @@ static int vmemmap_remap_free(unsigned l
vmemmap_remap_range(reuse, end, &walk);
}
- mmap_read_unlock(&init_mm);
return ret;
}
@@ -434,11 +429,7 @@ static int vmemmap_remap_alloc(unsigned
if (alloc_vmemmap_page_list(start, end, &vmemmap_pages))
return -ENOMEM;
- mmap_read_lock(&init_mm);
- vmemmap_remap_range(reuse, end, &walk);
- mmap_read_unlock(&init_mm);
-
- return 0;
+ return vmemmap_remap_range(reuse, end, &walk);
}
DEFINE_STATIC_KEY_FALSE(hugetlb_optimize_vmemmap_key);
_
Patches currently in -mm which might be from songmuchun@xxxxxxxxxxxxx are
mm-pagewalk-assert-write-mmap-lock-only-for-walking-the-user-page-tables.patch
mm-hugetlb_vmemmap-use-walk_page_range_novma-to-simplify-the-code.patch
mm-hugetlb_vmemmap-move-pagevmemmapselfhosted-check-to-split_vmemmap_huge_pmd.patch
mm-hugetlb_vmemmap-convert-page-to-folio.patch
mm-hugetlb_vmemmap-add-check-of-config_memory_hotplug-back.patch
mm-hugetlb_vmemmap-move-mmap-lock-to-vmemmap_remap_range.patch
