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parisc: Use per-pagetable spinlock

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PA-RISC uses a global spinlock to protect pagetable updates in the TLB
fault handlers. When multiple cores are taking TLB faults simultaneously,
the cache line containing the spinlock becomes a bottleneck.

This patch embeds the spinlock in the top level page directory, so that
every process has its own lock. It improves performance by 30% when
doing parallel compilations.

At least on the N class systems, only one PxTLB inter processor
broadcast can be active at any one time on the Merced bus. If a Merced
bus is found, this patch serializes the TLB flushes with the
pa_tlb_flush_lock spinlock.

v1: Initial patch by Mikulas
v2: Added Merced detection by Helge
v3: Revised TLB serialization by Dave & Helge

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
This commit is contained in:
Mikulas Patocka
2019-04-28 00:09:53 +02:00
committed by Helge Deller
parent d19a12906e
commit b37d1c1898
9 changed files with 108 additions and 49 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/parisc/include/asm/hardware.h
+1 -1
View File
@@ -120,7 +120,7 @@ extern void get_pci_node_path(struct pci_dev *dev, struct hardware_path *path);
extern void init_parisc_bus(void);
extern struct device *hwpath_to_device(struct hardware_path *modpath);
extern void device_to_hwpath(struct device *dev, struct hardware_path *path);
extern int machine_has_merced_bus(void);
/* inventory.c: */
extern void do_memory_inventory(void);
arch/parisc/include/asm/pgalloc.h
+1
View File
@@ -41,6 +41,7 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm)
__pgd_val_set(*pgd, PxD_FLAG_ATTACHED);
#endif
}
spin_lock_init(pgd_spinlock(actual_pgd));
return actual_pgd;
}
arch/parisc/include/asm/pgtable.h
+54 -15
View File
@@ -17,7 +17,7 @@
#include <asm/processor.h>
#include <asm/cache.h>
extern spinlock_t pa_tlb_lock;
static inline spinlock_t *pgd_spinlock(pgd_t *);
/*
* kern_addr_valid(ADDR) tests if ADDR is pointing to valid kernel
@@ -34,16 +34,46 @@ extern spinlock_t pa_tlb_lock;
*/
#define kern_addr_valid(addr) (1)
/* Purge data and instruction TLB entries. Must be called holding
* the pa_tlb_lock. The TLB purge instructions are slow on SMP
* machines since the purge must be broadcast to all CPUs.
/* This is for the serialization of PxTLB broadcasts. At least on the N class
* systems, only one PxTLB inter processor broadcast can be active at any one
* time on the Merced bus.
* PTE updates are protected by locks in the PMD.
*/
extern spinlock_t pa_tlb_flush_lock;
extern spinlock_t pa_swapper_pg_lock;
#if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
extern int pa_serialize_tlb_flushes;
#else
#define pa_serialize_tlb_flushes (0)
#endif
#define purge_tlb_start(flags) do { \
if (pa_serialize_tlb_flushes) \
spin_lock_irqsave(&pa_tlb_flush_lock, flags); \
else \
local_irq_save(flags); \
} while (0)
#define purge_tlb_end(flags) do { \
if (pa_serialize_tlb_flushes) \
spin_unlock_irqrestore(&pa_tlb_flush_lock, flags); \
else \
local_irq_restore(flags); \
} while (0)
/* Purge data and instruction TLB entries. The TLB purge instructions
* are slow on SMP machines since the purge must be broadcast to all CPUs.
*/
static inline void purge_tlb_entries(struct mm_struct *mm, unsigned long addr)
{
unsigned long flags;
purge_tlb_start(flags);
mtsp(mm->context, 1);
pdtlb(addr);
pitlb(addr);
purge_tlb_end(flags);
}
/* Certain architectures need to do special things when PTEs
@@ -59,11 +89,11 @@ static inline void purge_tlb_entries(struct mm_struct *mm, unsigned long addr)
do { \
pte_t old_pte; \
unsigned long flags; \
spin_lock_irqsave(&pa_tlb_lock, flags); \
spin_lock_irqsave(pgd_spinlock((mm)->pgd), flags);\
old_pte = *ptep; \
set_pte(ptep, pteval); \
purge_tlb_entries(mm, addr); \
spin_unlock_irqrestore(&pa_tlb_lock, flags); \
spin_unlock_irqrestore(pgd_spinlock((mm)->pgd), flags);\
} while (0)
#endif /* !__ASSEMBLY__ */
@@ -88,10 +118,10 @@ static inline void purge_tlb_entries(struct mm_struct *mm, unsigned long addr)
#if CONFIG_PGTABLE_LEVELS == 3
#define PGD_ORDER 1 /* Number of pages per pgd */
#define PMD_ORDER 1 /* Number of pages per pmd */
#define PGD_ALLOC_ORDER 2 /* first pgd contains pmd */
#define PGD_ALLOC_ORDER (2 + 1) /* first pgd contains pmd */
#else
#define PGD_ORDER 1 /* Number of pages per pgd */
#define PGD_ALLOC_ORDER PGD_ORDER
#define PGD_ALLOC_ORDER (PGD_ORDER + 1)
#endif
/* Definitions for 3rd level (we use PLD here for Page Lower directory
@@ -459,6 +489,15 @@ extern void update_mmu_cache(struct vm_area_struct *, unsigned long, pte_t *);
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
static inline spinlock_t *pgd_spinlock(pgd_t *pgd)
{
if (unlikely(pgd == swapper_pg_dir))
return &pa_swapper_pg_lock;
return (spinlock_t *)((char *)pgd + (PAGE_SIZE << (PGD_ALLOC_ORDER - 1)));
}
static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
{
pte_t pte;
@@ -467,15 +506,15 @@ static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned
if (!pte_young(*ptep))
return 0;
spin_lock_irqsave(&pa_tlb_lock, flags);
spin_lock_irqsave(pgd_spinlock(vma->vm_mm->pgd), flags);
pte = *ptep;
if (!pte_young(pte)) {
spin_unlock_irqrestore(&pa_tlb_lock, flags);
spin_unlock_irqrestore(pgd_spinlock(vma->vm_mm->pgd), flags);
return 0;
}
set_pte(ptep, pte_mkold(pte));
purge_tlb_entries(vma->vm_mm, addr);
spin_unlock_irqrestore(&pa_tlb_lock, flags);
spin_unlock_irqrestore(pgd_spinlock(vma->vm_mm->pgd), flags);
return 1;
}
@@ -485,11 +524,11 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
pte_t old_pte;
unsigned long flags;
spin_lock_irqsave(&pa_tlb_lock, flags);
spin_lock_irqsave(pgd_spinlock(mm->pgd), flags);
old_pte = *ptep;
set_pte(ptep, __pte(0));
purge_tlb_entries(mm, addr);
spin_unlock_irqrestore(&pa_tlb_lock, flags);
spin_unlock_irqrestore(pgd_spinlock(mm->pgd), flags);
return old_pte;
}
@@ -497,10 +536,10 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
unsigned long flags;
spin_lock_irqsave(&pa_tlb_lock, flags);
spin_lock_irqsave(pgd_spinlock(mm->pgd), flags);
set_pte(ptep, pte_wrprotect(*ptep));
purge_tlb_entries(mm, addr);
spin_unlock_irqrestore(&pa_tlb_lock, flags);
spin_unlock_irqrestore(pgd_spinlock(mm->pgd), flags);
}
#define pte_same(A,B) (pte_val(A) == pte_val(B))
arch/parisc/include/asm/tlbflush.h
+1 -23
View File
@@ -8,21 +8,6 @@
#include <linux/sched.h>
#include <asm/mmu_context.h>
/* This is for the serialisation of PxTLB broadcasts. At least on the
* N class systems, only one PxTLB inter processor broadcast can be
* active at any one time on the Merced bus. This tlb purge
* synchronisation is fairly lightweight and harmless so we activate
* it on all systems not just the N class.
* It is also used to ensure PTE updates are atomic and consistent
* with the TLB.
*/
extern spinlock_t pa_tlb_lock;
#define purge_tlb_start(flags) spin_lock_irqsave(&pa_tlb_lock, flags)
#define purge_tlb_end(flags) spin_unlock_irqrestore(&pa_tlb_lock, flags)
extern void flush_tlb_all(void);
extern void flush_tlb_all_local(void *);
@@ -79,13 +64,6 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
static inline void flush_tlb_page(struct vm_area_struct *vma,
unsigned long addr)
{
unsigned long flags, sid;
sid = vma->vm_mm->context;
purge_tlb_start(flags);
mtsp(sid, 1);
pdtlb(addr);
pitlb(addr);
purge_tlb_end(flags);
purge_tlb_entries(vma->vm_mm, addr);
}
#endif