Sharing page tables between processes but falling back to per-MM page
table locks cannot possibly work.
So, let's make sure that we do have split PMD locks by adding a new
Kconfig option and letting that depend on CONFIG_SPLIT_PMD_PTLOCKS.
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
fs/Kconfig | 4 ++++
include/linux/hugetlb.h | 5 ++---
mm/hugetlb.c | 8 ++++----
3 files changed, 10 insertions(+), 7 deletions(-)
diff --git a/fs/Kconfig b/fs/Kconfig
index a46b0cbc4d8f6..0e4efec1d92e6 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -288,6 +288,10 @@ config HUGETLB_PAGE_OPTIMIZE_VMEMMAP
depends on ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP
depends on SPARSEMEM_VMEMMAP
+config HUGETLB_PMD_PAGE_TABLE_SHARING
+ def_bool HUGETLB_PAGE
+ depends on ARCH_WANT_HUGE_PMD_SHARE && SPLIT_PMD_PTLOCKS
+
config ARCH_HAS_GIGANTIC_PAGE
bool
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index da800e56fe590..4d2f3224ff027 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -1243,7 +1243,7 @@ static inline __init void hugetlb_cma_reserve(int order)
}
#endif
-#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
+#ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING
static inline bool hugetlb_pmd_shared(pte_t *pte)
{
return page_count(virt_to_page(pte)) > 1;
@@ -1279,8 +1279,7 @@ bool __vma_private_lock(struct vm_area_struct *vma);
static inline pte_t *
hugetlb_walk(struct vm_area_struct *vma, unsigned long addr, unsigned long sz)
{
-#if defined(CONFIG_HUGETLB_PAGE) && \
- defined(CONFIG_ARCH_WANT_HUGE_PMD_SHARE) && defined(CONFIG_LOCKDEP)
+#if defined(CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING) && defined(CONFIG_LOCKDEP)
struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
/*
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 0858a18272073..c4d94e122c41f 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -7211,7 +7211,7 @@ long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
return 0;
}
-#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
+#ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING
static unsigned long page_table_shareable(struct vm_area_struct *svma,
struct vm_area_struct *vma,
unsigned long addr, pgoff_t idx)
@@ -7373,7 +7373,7 @@ int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
return 1;
}
-#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
+#else /* !CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING */
pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr, pud_t *pud)
@@ -7396,7 +7396,7 @@ bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
{
return false;
}
-#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
+#endif /* CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING */
#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
@@ -7494,7 +7494,7 @@ unsigned long hugetlb_mask_last_page(struct hstate *h)
/* See description above. Architectures can provide their own version. */
__weak unsigned long hugetlb_mask_last_page(struct hstate *h)
{
-#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
+#ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING
if (huge_page_size(h) == PMD_SIZE)
return PUD_SIZE - PMD_SIZE;
#endif
--
2.45.2
