staging: zsmalloc: add single-page object fastpath in unmap

Improve zs_unmap_object() performance by adding a fast path for
objects that don't span pages.

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/zsmalloc/zsmalloc-main.c b/drivers/staging/zsmalloc/zsmalloc-main.c
index a7a6f225bbffbb5d8700e33c50cdf23b150b192e..4942d419074bf45e442a3ad7e9f35f1bfd668d3f 100644 (file)
--- a/drivers/staging/zsmalloc/zsmalloc-main.c
+++ b/drivers/staging/zsmalloc/zsmalloc-main.c
@@ -774,6 +774,7 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle)
        }
 
        zs_copy_map_object(area->vm_buf, page, off, class->size);
+       area->vm_addr = NULL;
        return area->vm_buf;
 }
 EXPORT_SYMBOL_GPL(zs_map_object);
@@ -788,6 +789,14 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
        struct size_class *class;
        struct mapping_area *area;
 
+       area = &__get_cpu_var(zs_map_area);
+       if (area->vm_addr) {
+               /* single-page object fastpath */
+               kunmap_atomic(area->vm_addr);
+               put_cpu_var(zs_map_area);
+               return;
+       }
+
        BUG_ON(!handle);
 
        obj_handle_to_location(handle, &page, &obj_idx);
@@ -795,11 +804,7 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
        class = &pool->size_class[class_idx];
        off = obj_idx_to_offset(page, obj_idx, class->size);
 
-       area = &__get_cpu_var(zs_map_area);
-       if (off + class->size <= PAGE_SIZE)
-               kunmap_atomic(area->vm_addr);
-       else
-               zs_copy_unmap_object(area->vm_buf, page, off, class->size);
+       zs_copy_unmap_object(area->vm_buf, page, off, class->size);
        put_cpu_var(zs_map_area);
 }
 EXPORT_SYMBOL_GPL(zs_unmap_object);