[PATCH 2/2] [BONUS PATCH] mm: move tlb_flush_pending inline helpers to mm_inline.h
From: Arnd Bergmann
Date: Tue Dec 07 2021 - 07:59:05 EST
From: Arnd Bergmann <arnd@xxxxxxxx>
linux/mm_types.h should only define structure definitions, to make
it cheap to include elsewhere. The atomic_t helper function definitions
are particularly large, so it's better to move the helpers using those
into the existing linux/mm_inline.h and only include that where needed.
As a follow-up, we may want to go through all the indirect includes
in mm_types.h and reduce them as much as possible.
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
Bonus patch: unlike the previous one, this does not fix an
urgent bug, but rather cleans up the code along the same lines,
preparing for possible follow-up patches
---
arch/x86/include/asm/pgtable.h | 2 +-
include/linux/mm.h | 45 ------------
include/linux/mm_inline.h | 86 ++++++++++++++++++++++
include/linux/mm_types.h | 129 ++++++++++++---------------------
mm/ksm.c | 1 +
mm/mapping_dirty_helpers.c | 1 +
mm/memory.c | 1 +
mm/mmu_gather.c | 1 +
mm/pgtable-generic.c | 1 +
9 files changed, 137 insertions(+), 130 deletions(-)
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index ae34614b7e8d..d7d287ac1018 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -753,7 +753,7 @@ static inline bool pte_accessible(struct mm_struct *mm, pte_t a)
return true;
if ((pte_flags(a) & _PAGE_PROTNONE) &&
- mm_tlb_flush_pending(mm))
+ atomic_read(&mm->tlb_flush_pending))
return true;
return false;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 389c44691da9..44d75a8d1b92 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -425,51 +425,6 @@ extern unsigned int kobjsize(const void *objp);
*/
extern pgprot_t protection_map[16];
-/**
- * enum fault_flag - Fault flag definitions.
- * @FAULT_FLAG_WRITE: Fault was a write fault.
- * @FAULT_FLAG_MKWRITE: Fault was mkwrite of existing PTE.
- * @FAULT_FLAG_ALLOW_RETRY: Allow to retry the fault if blocked.
- * @FAULT_FLAG_RETRY_NOWAIT: Don't drop mmap_lock and wait when retrying.
- * @FAULT_FLAG_KILLABLE: The fault task is in SIGKILL killable region.
- * @FAULT_FLAG_TRIED: The fault has been tried once.
- * @FAULT_FLAG_USER: The fault originated in userspace.
- * @FAULT_FLAG_REMOTE: The fault is not for current task/mm.
- * @FAULT_FLAG_INSTRUCTION: The fault was during an instruction fetch.
- * @FAULT_FLAG_INTERRUPTIBLE: The fault can be interrupted by non-fatal signals.
- *
- * About @FAULT_FLAG_ALLOW_RETRY and @FAULT_FLAG_TRIED: we can specify
- * whether we would allow page faults to retry by specifying these two
- * fault flags correctly. Currently there can be three legal combinations:
- *
- * (a) ALLOW_RETRY and !TRIED: this means the page fault allows retry, and
- * this is the first try
- *
- * (b) ALLOW_RETRY and TRIED: this means the page fault allows retry, and
- * we've already tried at least once
- *
- * (c) !ALLOW_RETRY and !TRIED: this means the page fault does not allow retry
- *
- * The unlisted combination (!ALLOW_RETRY && TRIED) is illegal and should never
- * be used. Note that page faults can be allowed to retry for multiple times,
- * in which case we'll have an initial fault with flags (a) then later on
- * continuous faults with flags (b). We should always try to detect pending
- * signals before a retry to make sure the continuous page faults can still be
- * interrupted if necessary.
- */
-enum fault_flag {
- FAULT_FLAG_WRITE = 1 << 0,
- FAULT_FLAG_MKWRITE = 1 << 1,
- FAULT_FLAG_ALLOW_RETRY = 1 << 2,
- FAULT_FLAG_RETRY_NOWAIT = 1 << 3,
- FAULT_FLAG_KILLABLE = 1 << 4,
- FAULT_FLAG_TRIED = 1 << 5,
- FAULT_FLAG_USER = 1 << 6,
- FAULT_FLAG_REMOTE = 1 << 7,
- FAULT_FLAG_INSTRUCTION = 1 << 8,
- FAULT_FLAG_INTERRUPTIBLE = 1 << 9,
-};
-
/*
* The default fault flags that should be used by most of the
* arch-specific page fault handlers.
diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index 47d96d2647ca..b725839dfe71 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -2,6 +2,7 @@
#ifndef LINUX_MM_INLINE_H
#define LINUX_MM_INLINE_H
+#include <linux/atomic.h>
#include <linux/huge_mm.h>
#include <linux/swap.h>
#include <linux/string.h>
@@ -185,4 +186,89 @@ static inline bool is_same_vma_anon_name(struct vm_area_struct *vma,
}
#endif /* CONFIG_ANON_VMA_NAME */
+static inline void init_tlb_flush_pending(struct mm_struct *mm)
+{
+ atomic_set(&mm->tlb_flush_pending, 0);
+}
+
+static inline void inc_tlb_flush_pending(struct mm_struct *mm)
+{
+ atomic_inc(&mm->tlb_flush_pending);
+ /*
+ * The only time this value is relevant is when there are indeed pages
+ * to flush. And we'll only flush pages after changing them, which
+ * requires the PTL.
+ *
+ * So the ordering here is:
+ *
+ * atomic_inc(&mm->tlb_flush_pending);
+ * spin_lock(&ptl);
+ * ...
+ * set_pte_at();
+ * spin_unlock(&ptl);
+ *
+ * spin_lock(&ptl)
+ * mm_tlb_flush_pending();
+ * ....
+ * spin_unlock(&ptl);
+ *
+ * flush_tlb_range();
+ * atomic_dec(&mm->tlb_flush_pending);
+ *
+ * Where the increment if constrained by the PTL unlock, it thus
+ * ensures that the increment is visible if the PTE modification is
+ * visible. After all, if there is no PTE modification, nobody cares
+ * about TLB flushes either.
+ *
+ * This very much relies on users (mm_tlb_flush_pending() and
+ * mm_tlb_flush_nested()) only caring about _specific_ PTEs (and
+ * therefore specific PTLs), because with SPLIT_PTE_PTLOCKS and RCpc
+ * locks (PPC) the unlock of one doesn't order against the lock of
+ * another PTL.
+ *
+ * The decrement is ordered by the flush_tlb_range(), such that
+ * mm_tlb_flush_pending() will not return false unless all flushes have
+ * completed.
+ */
+}
+
+static inline void dec_tlb_flush_pending(struct mm_struct *mm)
+{
+ /*
+ * See inc_tlb_flush_pending().
+ *
+ * This cannot be smp_mb__before_atomic() because smp_mb() simply does
+ * not order against TLB invalidate completion, which is what we need.
+ *
+ * Therefore we must rely on tlb_flush_*() to guarantee order.
+ */
+ atomic_dec(&mm->tlb_flush_pending);
+}
+
+static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
+{
+ /*
+ * Must be called after having acquired the PTL; orders against that
+ * PTLs release and therefore ensures that if we observe the modified
+ * PTE we must also observe the increment from inc_tlb_flush_pending().
+ *
+ * That is, it only guarantees to return true if there is a flush
+ * pending for _this_ PTL.
+ */
+ return atomic_read(&mm->tlb_flush_pending);
+}
+
+static inline bool mm_tlb_flush_nested(struct mm_struct *mm)
+{
+ /*
+ * Similar to mm_tlb_flush_pending(), we must have acquired the PTL
+ * for which there is a TLB flush pending in order to guarantee
+ * we've seen both that PTE modification and the increment.
+ *
+ * (no requirement on actually still holding the PTL, that is irrelevant)
+ */
+ return atomic_read(&mm->tlb_flush_pending) > 1;
+}
+
+
#endif
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 555f51de1fe0..3764c1b51b02 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -692,90 +692,6 @@ extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm);
extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm);
extern void tlb_finish_mmu(struct mmu_gather *tlb);
-static inline void init_tlb_flush_pending(struct mm_struct *mm)
-{
- atomic_set(&mm->tlb_flush_pending, 0);
-}
-
-static inline void inc_tlb_flush_pending(struct mm_struct *mm)
-{
- atomic_inc(&mm->tlb_flush_pending);
- /*
- * The only time this value is relevant is when there are indeed pages
- * to flush. And we'll only flush pages after changing them, which
- * requires the PTL.
- *
- * So the ordering here is:
- *
- * atomic_inc(&mm->tlb_flush_pending);
- * spin_lock(&ptl);
- * ...
- * set_pte_at();
- * spin_unlock(&ptl);
- *
- * spin_lock(&ptl)
- * mm_tlb_flush_pending();
- * ....
- * spin_unlock(&ptl);
- *
- * flush_tlb_range();
- * atomic_dec(&mm->tlb_flush_pending);
- *
- * Where the increment if constrained by the PTL unlock, it thus
- * ensures that the increment is visible if the PTE modification is
- * visible. After all, if there is no PTE modification, nobody cares
- * about TLB flushes either.
- *
- * This very much relies on users (mm_tlb_flush_pending() and
- * mm_tlb_flush_nested()) only caring about _specific_ PTEs (and
- * therefore specific PTLs), because with SPLIT_PTE_PTLOCKS and RCpc
- * locks (PPC) the unlock of one doesn't order against the lock of
- * another PTL.
- *
- * The decrement is ordered by the flush_tlb_range(), such that
- * mm_tlb_flush_pending() will not return false unless all flushes have
- * completed.
- */
-}
-
-static inline void dec_tlb_flush_pending(struct mm_struct *mm)
-{
- /*
- * See inc_tlb_flush_pending().
- *
- * This cannot be smp_mb__before_atomic() because smp_mb() simply does
- * not order against TLB invalidate completion, which is what we need.
- *
- * Therefore we must rely on tlb_flush_*() to guarantee order.
- */
- atomic_dec(&mm->tlb_flush_pending);
-}
-
-static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
-{
- /*
- * Must be called after having acquired the PTL; orders against that
- * PTLs release and therefore ensures that if we observe the modified
- * PTE we must also observe the increment from inc_tlb_flush_pending().
- *
- * That is, it only guarantees to return true if there is a flush
- * pending for _this_ PTL.
- */
- return atomic_read(&mm->tlb_flush_pending);
-}
-
-static inline bool mm_tlb_flush_nested(struct mm_struct *mm)
-{
- /*
- * Similar to mm_tlb_flush_pending(), we must have acquired the PTL
- * for which there is a TLB flush pending in order to guarantee
- * we've seen both that PTE modification and the increment.
- *
- * (no requirement on actually still holding the PTL, that is irrelevant)
- */
- return atomic_read(&mm->tlb_flush_pending) > 1;
-}
-
struct vm_fault;
/**
@@ -890,4 +806,49 @@ typedef struct {
unsigned long val;
} swp_entry_t;
+/**
+ * enum fault_flag - Fault flag definitions.
+ * @FAULT_FLAG_WRITE: Fault was a write fault.
+ * @FAULT_FLAG_MKWRITE: Fault was mkwrite of existing PTE.
+ * @FAULT_FLAG_ALLOW_RETRY: Allow to retry the fault if blocked.
+ * @FAULT_FLAG_RETRY_NOWAIT: Don't drop mmap_lock and wait when retrying.
+ * @FAULT_FLAG_KILLABLE: The fault task is in SIGKILL killable region.
+ * @FAULT_FLAG_TRIED: The fault has been tried once.
+ * @FAULT_FLAG_USER: The fault originated in userspace.
+ * @FAULT_FLAG_REMOTE: The fault is not for current task/mm.
+ * @FAULT_FLAG_INSTRUCTION: The fault was during an instruction fetch.
+ * @FAULT_FLAG_INTERRUPTIBLE: The fault can be interrupted by non-fatal signals.
+ *
+ * About @FAULT_FLAG_ALLOW_RETRY and @FAULT_FLAG_TRIED: we can specify
+ * whether we would allow page faults to retry by specifying these two
+ * fault flags correctly. Currently there can be three legal combinations:
+ *
+ * (a) ALLOW_RETRY and !TRIED: this means the page fault allows retry, and
+ * this is the first try
+ *
+ * (b) ALLOW_RETRY and TRIED: this means the page fault allows retry, and
+ * we've already tried at least once
+ *
+ * (c) !ALLOW_RETRY and !TRIED: this means the page fault does not allow retry
+ *
+ * The unlisted combination (!ALLOW_RETRY && TRIED) is illegal and should never
+ * be used. Note that page faults can be allowed to retry for multiple times,
+ * in which case we'll have an initial fault with flags (a) then later on
+ * continuous faults with flags (b). We should always try to detect pending
+ * signals before a retry to make sure the continuous page faults can still be
+ * interrupted if necessary.
+ */
+enum fault_flag {
+ FAULT_FLAG_WRITE = 1 << 0,
+ FAULT_FLAG_MKWRITE = 1 << 1,
+ FAULT_FLAG_ALLOW_RETRY = 1 << 2,
+ FAULT_FLAG_RETRY_NOWAIT = 1 << 3,
+ FAULT_FLAG_KILLABLE = 1 << 4,
+ FAULT_FLAG_TRIED = 1 << 5,
+ FAULT_FLAG_USER = 1 << 6,
+ FAULT_FLAG_REMOTE = 1 << 7,
+ FAULT_FLAG_INSTRUCTION = 1 << 8,
+ FAULT_FLAG_INTERRUPTIBLE = 1 << 9,
+};
+
#endif /* _LINUX_MM_TYPES_H */
diff --git a/mm/ksm.c b/mm/ksm.c
index 4ce462dd31a4..c20bd4d9a0d9 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -15,6 +15,7 @@
#include <linux/errno.h>
#include <linux/mm.h>
+#include <linux/mm_inline.h>
#include <linux/fs.h>
#include <linux/mman.h>
#include <linux/sched.h>
diff --git a/mm/mapping_dirty_helpers.c b/mm/mapping_dirty_helpers.c
index ea734f248fce..1b0ab8fcfd8b 100644
--- a/mm/mapping_dirty_helpers.c
+++ b/mm/mapping_dirty_helpers.c
@@ -3,6 +3,7 @@
#include <linux/hugetlb.h>
#include <linux/bitops.h>
#include <linux/mmu_notifier.h>
+#include <linux/mm_inline.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
diff --git a/mm/memory.c b/mm/memory.c
index ced3274c3deb..674b3751965f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -41,6 +41,7 @@
#include <linux/kernel_stat.h>
#include <linux/mm.h>
+#include <linux/mm_inline.h>
#include <linux/sched/mm.h>
#include <linux/sched/coredump.h>
#include <linux/sched/numa_balancing.h>
diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c
index 1b9837419bf9..afb7185ffdc4 100644
--- a/mm/mmu_gather.c
+++ b/mm/mmu_gather.c
@@ -3,6 +3,7 @@
#include <linux/kernel.h>
#include <linux/mmdebug.h>
#include <linux/mm_types.h>
+#include <linux/mm_inline.h>
#include <linux/pagemap.h>
#include <linux/rcupdate.h>
#include <linux/smp.h>
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index 4e640baf9794..6523fda274e5 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -10,6 +10,7 @@
#include <linux/pagemap.h>
#include <linux/hugetlb.h>
#include <linux/pgtable.h>
+#include <linux/mm_inline.h>
#include <asm/tlb.h>
/*
--
2.29.2