From b74185108668ef966e663878adbad65e03bfcb43 Mon Sep 17 00:00:00 2001 From: Seth Jennings Date: Mon, 2 Jul 2012 16:15:52 -0500 Subject: staging: zsmalloc: add mapping modes This patch improves mapping performance in zsmalloc by getting usage information from the user in the form of a "mapping mode" and using it to avoid unnecessary copying for objects that span pages. Signed-off-by: Seth Jennings Signed-off-by: Greg Kroah-Hartman --- drivers/staging/zsmalloc/zsmalloc-main.c | 29 ++++++++++++++++++----------- 1 file changed, 18 insertions(+), 11 deletions(-) (limited to 'drivers/staging/zsmalloc/zsmalloc-main.c') diff --git a/drivers/staging/zsmalloc/zsmalloc-main.c b/drivers/staging/zsmalloc/zsmalloc-main.c index abf7c13c89c8..8b0bcb626a7f 100644 --- a/drivers/staging/zsmalloc/zsmalloc-main.c +++ b/drivers/staging/zsmalloc/zsmalloc-main.c @@ -484,9 +484,6 @@ static void zs_copy_map_object(char *buf, struct page *firstpage, sizes[0] = PAGE_SIZE - off; sizes[1] = size - sizes[0]; - /* disable page faults to match kmap_atomic() return conditions */ - pagefault_disable(); - /* copy object to per-cpu buffer */ addr = kmap_atomic(pages[0]); memcpy(buf, addr + off, sizes[0]); @@ -517,9 +514,6 @@ static void zs_copy_unmap_object(char *buf, struct page *firstpage, addr = kmap_atomic(pages[1]); memcpy(addr, buf + sizes[0], sizes[1]); kunmap_atomic(addr); - - /* enable page faults to match kunmap_atomic() return conditions */ - pagefault_enable(); } static int zs_cpu_notifier(struct notifier_block *nb, unsigned long action, @@ -754,7 +748,8 @@ EXPORT_SYMBOL_GPL(zs_free); * * This function returns with preemption and page faults disabled. */ -void *zs_map_object(struct zs_pool *pool, unsigned long handle) +void *zs_map_object(struct zs_pool *pool, unsigned long handle, + enum zs_mapmode mm) { struct page *page; unsigned long obj_idx, off; @@ -778,7 +773,11 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle) return area->vm_addr + off; } - zs_copy_map_object(area->vm_buf, page, off, class->size); + /* disable page faults to match kmap_atomic() return conditions */ + pagefault_disable(); + + if (mm != ZS_MM_WO) + zs_copy_map_object(area->vm_buf, page, off, class->size); area->vm_addr = NULL; return area->vm_buf; } @@ -795,13 +794,16 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle) struct mapping_area *area; area = &__get_cpu_var(zs_map_area); + /* single-page object fastpath */ if (area->vm_addr) { - /* single-page object fastpath */ kunmap_atomic(area->vm_addr); - put_cpu_var(zs_map_area); - return; + goto out; } + /* no write fastpath */ + if (area->vm_mm == ZS_MM_RO) + goto pfenable; + BUG_ON(!handle); obj_handle_to_location(handle, &page, &obj_idx); @@ -810,6 +812,11 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle) off = obj_idx_to_offset(page, obj_idx, class->size); zs_copy_unmap_object(area->vm_buf, page, off, class->size); + +pfenable: + /* enable page faults to match kunmap_atomic() return conditions */ + pagefault_enable(); +out: put_cpu_var(zs_map_area); } EXPORT_SYMBOL_GPL(zs_unmap_object); -- cgit v1.2.3-55-g7522