Re: [PATCHv4 0/6] mm/zpool: add common api for zswap to use zbud/zsmalloc

From: Bob Liu
Date: Tue Jun 03 2014 - 21:39:06 EST




On 06/03/2014 06:19 AM, Dan Streetman wrote:
> In order to allow zswap users to choose between zbud and zsmalloc for
> the compressed storage pool, this patch set adds a new api "zpool" that
> provides an interface to both zbud and zsmalloc. Only minor changes
> to zbud's interface were needed. This does not include implementing
> shrinking in zsmalloc, which will be sent separately.
>
> I believe Seth originally was using zsmalloc for swap, but there were
> concerns about how significant the impact of shrinking zsmalloc would
> be when zswap had to start reclaiming pages. That still may be an
> issue, but this at least allows users to choose themselves whether
> they want a lower-density or higher-density compressed storage medium.
> At least for situations where zswap reclaim is never or rarely reached,
> it probably makes sense to use the higher density of zsmalloc.
>

Nice job!
I also made a attempt last year, but didn't finish.

> Note this patch set does not change zram to use zpool, although that
> change should be possible as well.
>

This version looks good to me!

Reviewed-by: Bob Liu <bob.liu@xxxxxxxxxx>

> ---
>
> Changes since v3 : https://lkml.org/lkml/2014/5/24/130
> -In zpool_shrink() use # pages instead of # bytes
> -Add reclaimed param to zpool_shrink() to indicate to caller
> # pages actually reclaimed
> -move module usage counting to zpool, from zbud/zsmalloc
> -update zbud_zpool_shrink() to call zbud_reclaim_page() in a
> loop until requested # pages have been reclaimed (or error)
>
> Changes since v2 : https://lkml.org/lkml/2014/5/7/927
> -Change zpool to use driver registration instead of hardcoding
> implementations
> -Add module use counting in zbud/zsmalloc
>
> Changes since v1 https://lkml.org/lkml/2014/4/19/97
> -remove zsmalloc shrinking
> -change zbud size param type from unsigned int to size_t
> -remove zpool fallback creation
> -zswap manually falls back to zbud if specified type fails
>
>
> Dan Streetman (6):
> mm/zbud: zbud_alloc() minor param change
> mm/zbud: change zbud_alloc size type to size_t
> mm/zpool: implement common zpool api to zbud/zsmalloc
> mm/zpool: zbud/zsmalloc implement zpool
> mm/zpool: update zswap to use zpool
> mm/zpool: prevent zbud/zsmalloc from unloading when used
>
> include/linux/zbud.h | 2 +-
> include/linux/zpool.h | 224 ++++++++++++++++++++++++++++++++++++++++++++++++++
> mm/Kconfig | 43 ++++++----
> mm/Makefile | 1 +
> mm/zbud.c | 123 +++++++++++++++++++++++----
> mm/zpool.c | 206 ++++++++++++++++++++++++++++++++++++++++++++++
> mm/zsmalloc.c | 83 +++++++++++++++++++
> mm/zswap.c | 76 ++++++++++-------
> 8 files changed, 694 insertions(+), 64 deletions(-)
> create mode 100644 include/linux/zpool.h
> create mode 100644 mm/zpool.c
>

--
Regards,
-Bob
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