Re: [PATCH] mm/zsmalloc: fix comment in zsmalloc

From: Sergey Senozhatsky
Date: Wed Feb 08 2017 - 23:03:00 EST

On (02/09/17 11:23), Yisheng Xie wrote:
> The class index and fullness group are not encoded in
> (first)page->mapping any more, after commit 3783689a1aa8 ("zsmalloc:
> introduce zspage structure"). Instead, they are store in struct zspage.
> Cc: Minchan Kim <minchan@xxxxxxxxxx>
> Cc: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
> Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
> Cc: Hanjun Guo <guohanjun@xxxxxxxxxx>
> Signed-off-by: Yisheng Xie <xieyisheng1@xxxxxxxxxx>

no objections from my side.

Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>

a side note - may be we don't need this comment at all.
the code looks like this:

* A zspage's class index and fullness group
* are stored in struct zspage.
#define CLASS_BITS 8
#define MAGIC_VAL_BITS 8

struct zspage {
struct {
unsigned int fullness:FULLNESS_BITS;
unsigned int class:CLASS_BITS;
unsigned int isolated:ISOLATED_BITS;
unsigned int magic:MAGIC_VAL_BITS;
unsigned int inuse;
unsigned int freeobj;
struct page *first_page;
struct list_head list; /* fullness list */
rwlock_t lock;

so, basically, the comment just "repeats" the next 5 lines.
but, like I said, that's just a side note.