Re: + zsmalloc-add-comments-for-inuse-to-zspage.patch added to -mm tree

[Sergey Senozhatsky]

On (09/23/15 14:53), akpm@xxxxxxxxxxxxxxxxxxxx wrote:
> ------------------------------------------------------
> From: Hui Zhu <zhuhui@xxxxxxxxxx>
> Subject: zsmalloc: add comments for ->inuse to zspage
> 
> Signed-off-by: Hui Zhu <zhuhui@xxxxxxxxxx>
> Cc: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
> Cc: Dan Streetman <ddstreet@xxxxxxxx>
> Cc: Minchan Kim <minchan@xxxxxxxxxx>
> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> ---
> 
>  mm/zsmalloc.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> diff -puN mm/zsmalloc.c~zsmalloc-add-comments-for-inuse-to-zspage mm/zsmalloc.c
> --- a/mm/zsmalloc.c~zsmalloc-add-comments-for-inuse-to-zspage
> +++ a/mm/zsmalloc.c
> @@ -38,6 +38,7 @@
>   *	page->lru: links together first pages of various zspages.
>   *		Basically forming list of zspages in a fullness group.
>   *	page->mapping: class index and fullness group of the zspage
> + *	page->inuse: the pages number that is used in this zspage

Probably arrived last night to my another mailbox, so haven't
seen this one.


The comment is wrong. page ->inuse represents the number of objects
in use in this zspage; not "the pages number".

usage example:

zspage_full() : page->inuse == page->objects
obj_malloc() : first_page->inuse++
obj_free() : first_page->inuse--

	-ss
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