diff options
Diffstat (limited to 'mm/vmacache.c')
| -rw-r--r-- | mm/vmacache.c | 38 |
1 files changed, 29 insertions, 9 deletions
diff --git a/mm/vmacache.c b/mm/vmacache.c index db7596eb6132..ea517bef7dc5 100644 --- a/mm/vmacache.c +++ b/mm/vmacache.c @@ -6,6 +6,18 @@ #include <linux/sched/task.h> #include <linux/mm.h> #include <linux/vmacache.h> +#include <asm/pgtable.h> + +/* + * Hash based on the pmd of addr if configured with MMU, which provides a good + * hit rate for workloads with spatial locality. Otherwise, use pages. + */ +#ifdef CONFIG_MMU +#define VMACACHE_SHIFT PMD_SHIFT +#else +#define VMACACHE_SHIFT PAGE_SHIFT +#endif +#define VMACACHE_HASH(addr) ((addr >> VMACACHE_SHIFT) & VMACACHE_MASK) /* * Flush vma caches for threads that share a given mm. @@ -87,6 +99,7 @@ static bool vmacache_valid(struct mm_struct *mm) struct vm_area_struct *vmacache_find(struct mm_struct *mm, unsigned long addr) { + int idx = VMACACHE_HASH(addr); int i; count_vm_vmacache_event(VMACACHE_FIND_CALLS); @@ -95,16 +108,20 @@ struct vm_area_struct *vmacache_find(struct mm_struct *mm, unsigned long addr) return NULL; for (i = 0; i < VMACACHE_SIZE; i++) { - struct vm_area_struct *vma = current->vmacache.vmas[i]; + struct vm_area_struct *vma = current->vmacache.vmas[idx]; - if (!vma) - continue; - if (WARN_ON_ONCE(vma->vm_mm != mm)) - break; - if (vma->vm_start <= addr && vma->vm_end > addr) { - count_vm_vmacache_event(VMACACHE_FIND_HITS); - return vma; + if (vma) { +#ifdef CONFIG_DEBUG_VM_VMACACHE + if (WARN_ON_ONCE(vma->vm_mm != mm)) + break; +#endif + if (vma->vm_start <= addr && vma->vm_end > addr) { + count_vm_vmacache_event(VMACACHE_FIND_HITS); + return vma; + } } + if (++idx == VMACACHE_SIZE) + idx = 0; } return NULL; @@ -115,6 +132,7 @@ struct vm_area_struct *vmacache_find_exact(struct mm_struct *mm, unsigned long start, unsigned long end) { + int idx = VMACACHE_HASH(start); int i; count_vm_vmacache_event(VMACACHE_FIND_CALLS); @@ -123,12 +141,14 @@ struct vm_area_struct *vmacache_find_exact(struct mm_struct *mm, return NULL; for (i = 0; i < VMACACHE_SIZE; i++) { - struct vm_area_struct *vma = current->vmacache.vmas[i]; + struct vm_area_struct *vma = current->vmacache.vmas[idx]; if (vma && vma->vm_start == start && vma->vm_end == end) { count_vm_vmacache_event(VMACACHE_FIND_HITS); return vma; } + if (++idx == VMACACHE_SIZE) + idx = 0; } return NULL; |