Re: [PATCH v1 1/3] mm: turn USE_SPLIT_PTE_PTLOCKS / USE_SPLIT_PTE_PTLOCKS into Kconfig options
From: Qi Zheng
Date: Mon Jul 29 2024 - 03:57:13 EST
On 2024/7/26 23:07, David Hildenbrand wrote:
Let's clean that up a bit and prepare for depending on
CONFIG_SPLIT_PMD_PTLOCKS in other Kconfig options.
More cleanups would be reasonable (like the arch-specific "depends on"
for CONFIG_SPLIT_PTE_PTLOCKS), but we'll leave that for another day.
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
arch/arm/mm/fault-armv.c | 6 +++---
arch/x86/xen/mmu_pv.c | 7 ++++---
include/linux/mm.h | 8 ++++----
include/linux/mm_types.h | 2 +-
include/linux/mm_types_task.h | 3 ---
kernel/fork.c | 4 ++--
mm/Kconfig | 18 +++++++++++-------
mm/memory.c | 2 +-
8 files changed, 26 insertions(+), 24 deletions(-)
That's great. Thanks!
Reviewed-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c
index 2286c2ea60ec4..831793cd6ff94 100644
--- a/arch/arm/mm/fault-armv.c
+++ b/arch/arm/mm/fault-armv.c
@@ -61,7 +61,7 @@ static int do_adjust_pte(struct vm_area_struct *vma, unsigned long address,
return ret;
}
-#if USE_SPLIT_PTE_PTLOCKS
+#if defined(CONFIG_SPLIT_PTE_PTLOCKS)
/*
* If we are using split PTE locks, then we need to take the page
* lock here. Otherwise we are using shared mm->page_table_lock
@@ -80,10 +80,10 @@ static inline void do_pte_unlock(spinlock_t *ptl)
{
spin_unlock(ptl);
}
-#else /* !USE_SPLIT_PTE_PTLOCKS */
+#else /* !defined(CONFIG_SPLIT_PTE_PTLOCKS) */
static inline void do_pte_lock(spinlock_t *ptl) {}
static inline void do_pte_unlock(spinlock_t *ptl) {}
-#endif /* USE_SPLIT_PTE_PTLOCKS */
+#endif /* defined(CONFIG_SPLIT_PTE_PTLOCKS) */
static int adjust_pte(struct vm_area_struct *vma, unsigned long address,
unsigned long pfn)
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index f1ce39d6d32cb..f4a316894bbb4 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -665,7 +665,7 @@ static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
{
spinlock_t *ptl = NULL;
-#if USE_SPLIT_PTE_PTLOCKS
+#if defined(CONFIG_SPLIT_PTE_PTLOCKS)
ptl = ptlock_ptr(page_ptdesc(page));
spin_lock_nest_lock(ptl, &mm->page_table_lock);
#endif
@@ -1553,7 +1553,8 @@ static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
__set_pfn_prot(pfn, PAGE_KERNEL_RO);
- if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS && !pinned)
+ if (level == PT_PTE && IS_ENABLED(CONFIG_SPLIT_PTE_PTLOCKS) &&
+ !pinned)
__pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
xen_mc_issue(XEN_LAZY_MMU);
@@ -1581,7 +1582,7 @@ static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
if (pinned) {
xen_mc_batch();
- if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
+ if (level == PT_PTE && IS_ENABLED(CONFIG_SPLIT_PTE_PTLOCKS))
__pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
__set_pfn_prot(pfn, PAGE_KERNEL);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0472a5090b180..dff43101572ec 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2843,7 +2843,7 @@ static inline void pagetable_free(struct ptdesc *pt)
__free_pages(page, compound_order(page));
}
-#if USE_SPLIT_PTE_PTLOCKS
+#if defined(CONFIG_SPLIT_PTE_PTLOCKS)
#if ALLOC_SPLIT_PTLOCKS
void __init ptlock_cache_init(void);
bool ptlock_alloc(struct ptdesc *ptdesc);
@@ -2895,7 +2895,7 @@ static inline bool ptlock_init(struct ptdesc *ptdesc)
return true;
}
-#else /* !USE_SPLIT_PTE_PTLOCKS */
+#else /* !defined(CONFIG_SPLIT_PTE_PTLOCKS) */
/*
* We use mm->page_table_lock to guard all pagetable pages of the mm.
*/
@@ -2906,7 +2906,7 @@ static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pte_t *pte)
static inline void ptlock_cache_init(void) {}
static inline bool ptlock_init(struct ptdesc *ptdesc) { return true; }
static inline void ptlock_free(struct ptdesc *ptdesc) {}
-#endif /* USE_SPLIT_PTE_PTLOCKS */
+#endif /* defined(CONFIG_SPLIT_PTE_PTLOCKS) */
static inline bool pagetable_pte_ctor(struct ptdesc *ptdesc)
{
@@ -2966,7 +2966,7 @@ pte_t *pte_offset_map_nolock(struct mm_struct *mm, pmd_t *pmd,
((unlikely(pmd_none(*(pmd))) && __pte_alloc_kernel(pmd))? \
NULL: pte_offset_kernel(pmd, address))
-#if USE_SPLIT_PMD_PTLOCKS
+#if defined(CONFIG_SPLIT_PMD_PTLOCKS)
static inline struct page *pmd_pgtable_page(pmd_t *pmd)
{
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 4854249792545..165c58b12ccc9 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -947,7 +947,7 @@ struct mm_struct {
#ifdef CONFIG_MMU_NOTIFIER
struct mmu_notifier_subscriptions *notifier_subscriptions;
#endif
-#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !defined(CONFIG_SPLIT_PMD_PTLOCKS)
pgtable_t pmd_huge_pte; /* protected by page_table_lock */
#endif
#ifdef CONFIG_NUMA_BALANCING
diff --git a/include/linux/mm_types_task.h b/include/linux/mm_types_task.h
index a2f6179b672b8..bff5706b76e14 100644
--- a/include/linux/mm_types_task.h
+++ b/include/linux/mm_types_task.h
@@ -16,9 +16,6 @@
#include <asm/tlbbatch.h>
#endif
-#define USE_SPLIT_PTE_PTLOCKS (NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS)
-#define USE_SPLIT_PMD_PTLOCKS (USE_SPLIT_PTE_PTLOCKS && \
- IS_ENABLED(CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK))
#define ALLOC_SPLIT_PTLOCKS (SPINLOCK_SIZE > BITS_PER_LONG/8)
/*
diff --git a/kernel/fork.c b/kernel/fork.c
index a8362c26ebcb0..216ce9ba4f4e6 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -832,7 +832,7 @@ static void check_mm(struct mm_struct *mm)
pr_alert("BUG: non-zero pgtables_bytes on freeing mm: %ld\n",
mm_pgtables_bytes(mm));
-#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !defined(CONFIG_SPLIT_PMD_PTLOCKS)
VM_BUG_ON_MM(mm->pmd_huge_pte, mm);
#endif
}
@@ -1276,7 +1276,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
RCU_INIT_POINTER(mm->exe_file, NULL);
mmu_notifier_subscriptions_init(mm);
init_tlb_flush_pending(mm);
-#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !defined(CONFIG_SPLIT_PMD_PTLOCKS)
mm->pmd_huge_pte = NULL;
#endif
mm_init_uprobes_state(mm);
diff --git a/mm/Kconfig b/mm/Kconfig
index b72e7d040f789..7b716ac802726 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -585,17 +585,21 @@ config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
# at the same time (e.g. copy_page_range()).
# DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC spinlock_t also enlarge struct page.
#
-config SPLIT_PTLOCK_CPUS
- int
- default "999999" if !MMU
- default "999999" if ARM && !CPU_CACHE_VIPT
- default "999999" if PARISC && !PA20
- default "999999" if SPARC32
- default "4"
+config SPLIT_PTE_PTLOCKS
+ def_bool y
+ depends on MMU
+ depends on NR_CPUS >= 4
+ depends on !ARM || CPU_CACHE_VIPT
+ depends on !PARISC || PA20
+ depends on !SPARC32
config ARCH_ENABLE_SPLIT_PMD_PTLOCK
bool
+config SPLIT_PMD_PTLOCKS
+ def_bool y
+ depends on SPLIT_PTE_PTLOCKS && ARCH_ENABLE_SPLIT_PMD_PTLOCK
+
#
# support for memory balloon
config MEMORY_BALLOON
diff --git a/mm/memory.c b/mm/memory.c
index 833d2cad6eb29..714589582fe15 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -6559,7 +6559,7 @@ long copy_folio_from_user(struct folio *dst_folio,
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
-#if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS
+#if defined(CONFIG_SPLIT_PTE_PTLOCKS) && ALLOC_SPLIT_PTLOCKS
static struct kmem_cache *page_ptl_cachep;