diff options
| author | Chris Wilson <chris@chris-wilson.co.uk> | 2016-05-20 16:57:38 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-20 17:58:30 -0700 |
| commit | 80c4bd7a5e4368b680e0aeb57050a1b06eb573d8 (patch) | |
| tree | 248bfb6e975a03f0a164e38de844f48053980158 /mm/vmalloc.c | |
| parent | f705ac4b39f30a6a5f8411a42114758f4d4655bc (diff) | |
mm/vmalloc: keep a separate lazy-free list
When mixing lots of vmallocs and set_memory_*() (which calls
vm_unmap_aliases()) I encountered situations where the performance
degraded severely due to the walking of the entire vmap_area list each
invocation.
One simple improvement is to add the lazily freed vmap_area to a
separate lockless free list, such that we then avoid having to walk the
full list on each purge.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Roman Pen <r.peniaev@gmail.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Roman Pen <r.peniaev@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmalloc.c')
| -rw-r--r-- | mm/vmalloc.c | 39 |
1 files changed, 19 insertions, 20 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index ae7d20b447ff..6e3291882739 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -274,13 +274,12 @@ EXPORT_SYMBOL(vmalloc_to_pfn); /*** Global kva allocator ***/ -#define VM_LAZY_FREE 0x01 -#define VM_LAZY_FREEING 0x02 #define VM_VM_AREA 0x04 static DEFINE_SPINLOCK(vmap_area_lock); /* Export for kexec only */ LIST_HEAD(vmap_area_list); +static LLIST_HEAD(vmap_purge_list); static struct rb_root vmap_area_root = RB_ROOT; /* The vmap cache globals are protected by vmap_area_lock */ @@ -601,7 +600,7 @@ static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end, int sync, int force_flush) { static DEFINE_SPINLOCK(purge_lock); - LIST_HEAD(valist); + struct llist_node *valist; struct vmap_area *va; struct vmap_area *n_va; int nr = 0; @@ -620,20 +619,14 @@ static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end, if (sync) purge_fragmented_blocks_allcpus(); - rcu_read_lock(); - list_for_each_entry_rcu(va, &vmap_area_list, list) { - if (va->flags & VM_LAZY_FREE) { - if (va->va_start < *start) - *start = va->va_start; - if (va->va_end > *end) - *end = va->va_end; - nr += (va->va_end - va->va_start) >> PAGE_SHIFT; - list_add_tail(&va->purge_list, &valist); - va->flags |= VM_LAZY_FREEING; - va->flags &= ~VM_LAZY_FREE; - } + valist = llist_del_all(&vmap_purge_list); + llist_for_each_entry(va, valist, purge_list) { + if (va->va_start < *start) + *start = va->va_start; + if (va->va_end > *end) + *end = va->va_end; + nr += (va->va_end - va->va_start) >> PAGE_SHIFT; } - rcu_read_unlock(); if (nr) atomic_sub(nr, &vmap_lazy_nr); @@ -643,7 +636,7 @@ static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end, if (nr) { spin_lock(&vmap_area_lock); - list_for_each_entry_safe(va, n_va, &valist, purge_list) + llist_for_each_entry_safe(va, n_va, valist, purge_list) __free_vmap_area(va); spin_unlock(&vmap_area_lock); } @@ -678,9 +671,15 @@ static void purge_vmap_area_lazy(void) */ static void free_vmap_area_noflush(struct vmap_area *va) { - va->flags |= VM_LAZY_FREE; - atomic_add((va->va_end - va->va_start) >> PAGE_SHIFT, &vmap_lazy_nr); - if (unlikely(atomic_read(&vmap_lazy_nr) > lazy_max_pages())) + int nr_lazy; + + nr_lazy = atomic_add_return((va->va_end - va->va_start) >> PAGE_SHIFT, + &vmap_lazy_nr); + + /* After this point, we may free va at any time */ + llist_add(&va->purge_list, &vmap_purge_list); + + if (unlikely(nr_lazy > lazy_max_pages())) try_purge_vmap_area_lazy(); } |