diff options
| -rw-r--r-- | fs/proc/task_mmu.c | 2 | ||||
| -rw-r--r-- | include/linux/mm.h | 2 | ||||
| -rw-r--r-- | include/linux/mm_types.h | 10 | ||||
| -rw-r--r-- | include/linux/sched/coredump.h | 8 | ||||
| -rw-r--r-- | kernel/fork.c | 1 | ||||
| -rw-r--r-- | mm/gup.c | 19 |
6 files changed, 25 insertions, 17 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index fc9784544b24..66965ad88d8b 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1047,7 +1047,7 @@ static inline bool pte_is_pinned(struct vm_area_struct *vma, unsigned long addr, return false; if (!is_cow_mapping(vma->vm_flags)) return false; - if (likely(!atomic_read(&vma->vm_mm->has_pinned))) + if (likely(!test_bit(MMF_HAS_PINNED, &vma->vm_mm->flags))) return false; page = vm_normal_page(vma, addr, pte); if (!page) diff --git a/include/linux/mm.h b/include/linux/mm.h index e39ed497578b..79f32962d7ae 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1341,7 +1341,7 @@ static inline bool page_needs_cow_for_dma(struct vm_area_struct *vma, if (!is_cow_mapping(vma->vm_flags)) return false; - if (!atomic_read(&vma->vm_mm->has_pinned)) + if (!test_bit(MMF_HAS_PINNED, &vma->vm_mm->flags)) return false; return page_maybe_dma_pinned(page); diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 8f0fb62e8975..b66d0225414e 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -435,16 +435,6 @@ struct mm_struct { */ atomic_t mm_count; - /** - * @has_pinned: Whether this mm has pinned any pages. This can - * be either replaced in the future by @pinned_vm when it - * becomes stable, or grow into a counter on its own. We're - * aggresive on this bit now - even if the pinned pages were - * unpinned later on, we'll still keep this bit set for the - * lifecycle of this mm just for simplicity. - */ - atomic_t has_pinned; - #ifdef CONFIG_MMU atomic_long_t pgtables_bytes; /* PTE page table pages */ #endif diff --git a/include/linux/sched/coredump.h b/include/linux/sched/coredump.h index dfd82eab2902..4d9e3a656875 100644 --- a/include/linux/sched/coredump.h +++ b/include/linux/sched/coredump.h @@ -73,6 +73,14 @@ static inline int get_dumpable(struct mm_struct *mm) #define MMF_OOM_VICTIM 25 /* mm is the oom victim */ #define MMF_OOM_REAP_QUEUED 26 /* mm was queued for oom_reaper */ #define MMF_MULTIPROCESS 27 /* mm is shared between processes */ +/* + * MMF_HAS_PINNED: Whether this mm has pinned any pages. This can be either + * replaced in the future by mm.pinned_vm when it becomes stable, or grow into + * a counter on its own. We're aggresive on this bit for now: even if the + * pinned pages were unpinned later on, we'll still keep this bit set for the + * lifecycle of this mm, just for simplicity. + */ +#define MMF_HAS_PINNED 28 /* FOLL_PIN has run, never cleared */ #define MMF_DISABLE_THP_MASK (1 << MMF_DISABLE_THP) #define MMF_INIT_MASK (MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK |\ diff --git a/kernel/fork.c b/kernel/fork.c index a070caed5c8e..c6747d556ef9 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1029,7 +1029,6 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, mm_pgtables_bytes_init(mm); mm->map_count = 0; mm->locked_vm = 0; - atomic_set(&mm->has_pinned, 0); atomic64_set(&mm->pinned_vm, 0); memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); spin_lock_init(&mm->page_table_lock); @@ -420,6 +420,17 @@ void unpin_user_pages(struct page **pages, unsigned long npages) } EXPORT_SYMBOL(unpin_user_pages); +/* + * Set the MMF_HAS_PINNED if not set yet; after set it'll be there for the mm's + * lifecycle. Avoid setting the bit unless necessary, or it might cause write + * cache bouncing on large SMP machines for concurrent pinned gups. + */ +static inline void mm_set_has_pinned_flag(unsigned long *mm_flags) +{ + if (!test_bit(MMF_HAS_PINNED, mm_flags)) + set_bit(MMF_HAS_PINNED, mm_flags); +} + #ifdef CONFIG_MMU static struct page *no_page_table(struct vm_area_struct *vma, unsigned int flags) @@ -1320,8 +1331,8 @@ static __always_inline long __get_user_pages_locked(struct mm_struct *mm, BUG_ON(*locked != 1); } - if ((flags & FOLL_PIN) && !atomic_read(&mm->has_pinned)) - atomic_set(&mm->has_pinned, 1); + if (flags & FOLL_PIN) + mm_set_has_pinned_flag(&mm->flags); /* * FOLL_PIN and FOLL_GET are mutually exclusive. Traditional behavior @@ -2641,8 +2652,8 @@ static int internal_get_user_pages_fast(unsigned long start, FOLL_FAST_ONLY))) return -EINVAL; - if ((gup_flags & FOLL_PIN) && !atomic_read(¤t->mm->has_pinned)) - atomic_set(¤t->mm->has_pinned, 1); + if (gup_flags & FOLL_PIN) + mm_set_has_pinned_flag(¤t->mm->flags); if (!(gup_flags & FOLL_FAST_ONLY)) might_lock_read(¤t->mm->mmap_lock); |