mm/vmalloc.c: refactor __vunmap() to avoid duplicated call to find_vm_area()
__vunmap() calls find_vm_area() twice without an obvious reason: first
directly to get the area pointer, second indirectly by calling
remove_vm_area(), which is again searching for the area.
To remove this redundancy, let's split remove_vm_area() into
__remove_vm_area(struct vmap_area *), which performs the actual area
removal, and remove_vm_area(const void *addr) wrapper, which can be used
everywhere, where it has been used before.
On my test setup, I've got 5-10% speed up on vfree()'ing 1000000 of
4-pages vmalloc blocks.
Perf report before:
22.64% cat [kernel.vmlinux] [k] free_pcppages_bulk
10.30% cat [kernel.vmlinux] [k] __vunmap
9.80% cat [kernel.vmlinux] [k] find_vmap_area
8.11% cat [kernel.vmlinux] [k] vunmap_page_range
4.20% cat [kernel.vmlinux] [k] __slab_free
3.56% cat [kernel.vmlinux] [k] __list_del_entry_valid
3.46% cat [kernel.vmlinux] [k] smp_call_function_many
3.33% cat [kernel.vmlinux] [k] kfree
3.32% cat [kernel.vmlinux] [k] free_unref_page
Perf report after:
23.01% cat [kernel.kallsyms] [k] free_pcppages_bulk
9.46% cat [kernel.kallsyms] [k] __vunmap
9.15% cat [kernel.kallsyms] [k] vunmap_page_range
6.17% cat [kernel.kallsyms] [k] __slab_free
5.61% cat [kernel.kallsyms] [k] kfree
4.86% cat [kernel.kallsyms] [k] bad_range
4.67% cat [kernel.kallsyms] [k] free_unref_page_commit
4.24% cat [kernel.kallsyms] [k] __list_del_entry_valid
3.68% cat [kernel.kallsyms] [k] free_unref_page
3.65% cat [kernel.kallsyms] [k] __list_add_valid
3.19% cat [kernel.kallsyms] [k] __purge_vmap_area_lazy
3.10% cat [kernel.kallsyms] [k] find_vmap_area
3.05% cat [kernel.kallsyms] [k] rcu_cblist_dequeue
Link: http://lkml.kernel.org/r/20190417194002.12369-2-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Git-commit: e97ad926639fef3930abb72b1f5588d655ee4d74
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Change-Id: Id734ceca4b12c9445bf5166794aa49bea92ec402
Signed-off-by: Vijayanand Jitta <vjitta@codeaurora.org>
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index a728fc4..a4c16fc 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1462,6 +1462,24 @@
return NULL;
}
+static struct vm_struct *__remove_vm_area(struct vmap_area *va)
+{
+ struct vm_struct *vm = va->vm;
+
+ might_sleep();
+
+ spin_lock(&vmap_area_lock);
+ va->vm = NULL;
+ va->flags &= ~VM_VM_AREA;
+ va->flags |= VM_LAZY_FREE;
+ spin_unlock(&vmap_area_lock);
+
+ kasan_free_shadow(vm);
+ free_unmap_vmap_area(va);
+
+ return vm;
+}
+
/**
* remove_vm_area - find and remove a continuous kernel virtual area
* @addr: base address
@@ -1472,31 +1490,20 @@
*/
struct vm_struct *remove_vm_area(const void *addr)
{
+ struct vm_struct *vm = NULL;
struct vmap_area *va;
- might_sleep();
-
va = find_vmap_area((unsigned long)addr);
- if (va && va->flags & VM_VM_AREA) {
- struct vm_struct *vm = va->vm;
+ if (va && va->flags & VM_VM_AREA)
+ vm = __remove_vm_area(va);
- spin_lock(&vmap_area_lock);
- va->vm = NULL;
- va->flags &= ~VM_VM_AREA;
- va->flags |= VM_LAZY_FREE;
- spin_unlock(&vmap_area_lock);
-
- kasan_free_shadow(vm);
- free_unmap_vmap_area(va);
-
- return vm;
- }
- return NULL;
+ return vm;
}
static void __vunmap(const void *addr, int deallocate_pages)
{
struct vm_struct *area;
+ struct vmap_area *va;
if (!addr)
return;
@@ -1505,17 +1512,18 @@
addr))
return;
- area = find_vmap_area((unsigned long)addr)->vm;
- if (unlikely(!area)) {
+ va = find_vmap_area((unsigned long)addr);
+ if (unlikely(!va || !(va->flags & VM_VM_AREA))) {
WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
addr);
return;
}
- debug_check_no_locks_freed(area->addr, get_vm_area_size(area));
- debug_check_no_obj_freed(area->addr, get_vm_area_size(area));
+ area = va->vm;
+ debug_check_no_locks_freed(addr, get_vm_area_size(area));
+ debug_check_no_obj_freed(addr, get_vm_area_size(area));
- remove_vm_area(addr);
+ __remove_vm_area(va);
if (deallocate_pages) {
int i;
@@ -1530,7 +1538,6 @@
}
kfree(area);
- return;
}
static inline void __vfree_deferred(const void *addr)