On Fri, Jul 01, 2016 at 02:41:03PM +0800, Ganesh Mahendran wrote:
> Currently, if a class can not be merged, the max objects of zspage
> in that class may be calculated twice.
>
> This patch calculate max objects of zspage at the begin, and pass
> the value to can_merge() to decide whether the class can be merged.
>
> Signed-off-by: Ganesh Mahendran <opensource.ganesh@xxxxxxxxx>
> ---
> mm/zsmalloc.c | 21 ++++++++++-----------
> 1 file changed, 10 insertions(+), 11 deletions(-)
>
> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> index 50283b1..2690914 100644
> --- a/mm/zsmalloc.c
> +++ b/mm/zsmalloc.c
> @@ -1362,16 +1362,14 @@ static void init_zs_size_classes(void)
> zs_size_classes = nr;
> }
>
> -static bool can_merge(struct size_class *prev, int size, int pages_per_zspage)
> +static bool can_merge(struct size_class *prev, int pages_per_zspage,
> + int objs_per_zspage)
> {
> - if (prev->pages_per_zspage != pages_per_zspage)
> - return false;
> -
> - if (prev->objs_per_zspage
> - != get_maxobj_per_zspage(size, pages_per_zspage))
> - return false;
> + if (prev->pages_per_zspage == pages_per_zspage &&
> + prev->objs_per_zspage == objs_per_zspage)
> + return true;
>
> - return true;
> + return false;
> }
>
> static bool zspage_full(struct size_class *class, struct zspage *zspage)
> @@ -2460,6 +2458,7 @@ struct zs_pool *zs_create_pool(const char *name)
> for (i = zs_size_classes - 1; i >= 0; i--) {
> int size;
> int pages_per_zspage;
> + int objs_per_zspage;
> struct size_class *class;
> int fullness = 0;
>
> @@ -2467,6 +2466,7 @@ struct zs_pool *zs_create_pool(const char *name)
> if (size > ZS_MAX_ALLOC_SIZE)
> size = ZS_MAX_ALLOC_SIZE;
> pages_per_zspage = get_pages_per_zspage(size);
> + objs_per_zspage = get_maxobj_per_zspage(size, pages_per_zspage);
So, user of get_maxobj_per_zspage is only here? If so, let's remove
get_maxobj_per_zspage to prevent misuse in future. Instead, use open code
here.
>
> /*
> * size_class is used for normal zsmalloc operation such
> @@ -2478,7 +2478,7 @@ struct zs_pool *zs_create_pool(const char *name)
> * previous size_class if possible.
> */
> if (prev_class) {
> - if (can_merge(prev_class, size, pages_per_zspage)) {
> + if (can_merge(prev_class, pages_per_zspage, objs_per_zspage)) {
> pool->size_class[i] = prev_class;
> continue;
> }
> @@ -2491,8 +2491,7 @@ struct zs_pool *zs_create_pool(const char *name)
> class->size = size;
> class->index = i;
> class->pages_per_zspage = pages_per_zspage;
> - class->objs_per_zspage = get_maxobj_per_zspage(class->size,
> - class->pages_per_zspage);
> + class->objs_per_zspage = objs_per_zspage;
> spin_lock_init(&class->lock);
> pool->size_class[i] = class;
> for (fullness = ZS_EMPTY; fullness < NR_ZS_FULLNESS;
> --
> 1.9.1
>
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