Just resent new one with correcting Seth's mail address and including the one
omitted by mistake in this patchset.
On Thu, Aug 14, 2014 at 09:57:56AM +0900, Minchan Kim wrote:
> Pages_allocated has counted in size_class structure and when user
> want to see total_size_bytes, it gathers all of value from each
> size_class to report the sum.
>
> It's not bad if user don't see the value often but if user start
> to see the value frequently, it would be not a good deal for
> performance POV.
>
> Even, this patch moves the variable from size_class to zs_pool
> so it reduces memory footprint (from [255 * 8byte] to
> [sizeof(atomic_t)]) but it introduce new atomic opearation
> but it's not a big deal because atomic operation is called on
> slow path of zsmalloc where it allocates/free zspage unit,
> not object.
>
> Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
> ---
> mm/zsmalloc.c | 21 +++++++--------------
> 1 file changed, 7 insertions(+), 14 deletions(-)
>
> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> index 4e2fc83cb394..2f21ea8921dc 100644
> --- a/mm/zsmalloc.c
> +++ b/mm/zsmalloc.c
> @@ -199,9 +199,6 @@ struct size_class {
>
> spinlock_t lock;
>
> - /* stats */
> - u64 pages_allocated;
> -
> struct page *fullness_list[_ZS_NR_FULLNESS_GROUPS];
> };
>
> @@ -220,6 +217,7 @@ struct zs_pool {
> struct size_class size_class[ZS_SIZE_CLASSES];
>
> gfp_t flags; /* allocation flags used when growing pool */
> + atomic_t pages_allocated;
> };
>
> /*
> @@ -1027,8 +1025,8 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size)
> return 0;
>
> set_zspage_mapping(first_page, class->index, ZS_EMPTY);
> + atomic_add(class->pages_per_zspage, &pool->pages_allocated);
> spin_lock(&class->lock);
> - class->pages_allocated += class->pages_per_zspage;
> }
>
> obj = (unsigned long)first_page->freelist;
> @@ -1081,14 +1079,12 @@ void zs_free(struct zs_pool *pool, unsigned long obj)
>
> first_page->inuse--;
> fullness = fix_fullness_group(pool, first_page);
> -
> - if (fullness == ZS_EMPTY)
> - class->pages_allocated -= class->pages_per_zspage;
> -
> spin_unlock(&class->lock);
>
> - if (fullness == ZS_EMPTY)
> + if (fullness == ZS_EMPTY) {
> + atomic_sub(class->pages_per_zspage, &pool->pages_allocated);
> free_zspage(first_page);
> + }
> }
> EXPORT_SYMBOL_GPL(zs_free);
>
> @@ -1184,12 +1180,9 @@ EXPORT_SYMBOL_GPL(zs_unmap_object);
>
> u64 zs_get_total_size_bytes(struct zs_pool *pool)
> {
> - int i;
> - u64 npages = 0;
> -
> - for (i = 0; i < ZS_SIZE_CLASSES; i++)
> - npages += pool->size_class[i].pages_allocated;
> + u64 npages;
>
> + npages = atomic_read(&pool->pages_allocated);
> return npages << PAGE_SHIFT;
> }
> EXPORT_SYMBOL_GPL(zs_get_total_size_bytes);
> --
> 2.0.0
--
Kind regards,
Minchan Kim
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