From: Minchan Kim <minchan@kernel.org>
To: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Dan Magenheimer <dan.magenheimer@oracle.com>,
Nitin Gupta <ngupta@vflare.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 3/4] zsmalloc use zs_handle instead of void *
Date: Mon, 14 May 2012 11:26:20 +0900 [thread overview]
Message-ID: <4FB06D4C.1050209@kernel.org> (raw)
In-Reply-To: <4FAD8984.2050201@linux.vnet.ibm.com>
On 05/12/2012 06:49 AM, Seth Jennings wrote:
> On 05/11/2012 02:29 PM, Konrad Rzeszutek Wilk wrote:
>
>>> At least, zram is also primary user and it also has such mess
>>> although it's not severe than zcache. zram->table[index].handle
>>> sometime has real (void*) handle, sometime (struct page*).
>>
>> Yikes. Yeah that needs to be fixed.
>>
>
>
> How about this (untested)? Changes to zram_bvec_write() are a little
> hard to make out in this format. There are a couple of checkpatch fixes
> (two split line strings) and an unused variable store_offset removal mixed
> in too. If this patch is good, I'll break them up for official submission
> after I test.
>
> diff --git a/drivers/staging/zram/zram_drv.h b/drivers/staging/zram/zram_drv.h
> index fbe8ac9..10dcd99 100644
> --- a/drivers/staging/zram/zram_drv.h
> +++ b/drivers/staging/zram/zram_drv.h
> @@ -81,7 +81,10 @@ enum zram_pageflags {
>
> /* Allocated for each disk page */
> struct table {
> - void *handle;
> + union {
> + void *handle; /* compressible */
> + struct page *page; /* incompressible */
You read my mind. That's exactly same idea with my patch which queued up to my tree.
But there is still problem.
zram has like this code
void *handle = zram->table[index].handle;
if (!handle) {
}
zram->table[index].handle = NULL;
It assume handle's size is greater than or equal to sizeof(struct page*)) for union working.
But we can't make sure handle's size.
If Nitin confirm this, too, the problem would be easy to fix.
--
Kind regards,
Minchan Kim
next prev parent reply other threads:[~2012-05-14 2:25 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-03 6:40 [PATCH 1/4] zsmalloc: rename zspage_order with zspage_pages Minchan Kim
2012-05-03 6:40 ` [PATCH 2/4] zsmalloc: add/fix function comment Minchan Kim
2012-05-03 13:19 ` Nitin Gupta
2012-05-03 6:40 ` [PATCH 3/4] zsmalloc use zs_handle instead of void * Minchan Kim
2012-05-03 13:32 ` Nitin Gupta
2012-05-03 15:23 ` Seth Jennings
2012-05-04 2:24 ` Minchan Kim
2012-05-07 15:01 ` Seth Jennings
2012-05-09 20:19 ` Greg Kroah-Hartman
2012-05-10 2:03 ` Minchan Kim
2012-05-10 14:02 ` Konrad Rzeszutek Wilk
2012-05-10 14:12 ` Greg Kroah-Hartman
2012-05-10 14:47 ` Nitin Gupta
2012-05-10 15:00 ` Minchan Kim
2012-05-10 15:11 ` Seth Jennings
2012-05-10 15:19 ` Minchan Kim
2012-05-10 15:19 ` Greg Kroah-Hartman
2012-05-10 16:29 ` Nitin Gupta
2012-05-10 16:44 ` Greg Kroah-Hartman
2012-05-10 17:24 ` Nitin Gupta
2012-05-10 17:33 ` Konrad Rzeszutek Wilk
2012-05-10 23:24 ` Minchan Kim
2012-05-10 23:50 ` Dan Magenheimer
2012-05-11 0:14 ` Minchan Kim
2012-05-11 16:31 ` Dan Magenheimer
2012-05-11 19:29 ` Konrad Rzeszutek Wilk
2012-05-11 21:49 ` Seth Jennings
2012-05-14 2:26 ` Minchan Kim [this message]
2012-05-11 19:28 ` Konrad Rzeszutek Wilk
2012-05-14 2:18 ` Minchan Kim
2012-05-15 1:57 ` Nitin Gupta
2012-05-15 2:21 ` Minchan Kim
2012-05-15 15:04 ` Konrad Rzeszutek Wilk
2012-05-16 1:36 ` Minchan Kim
2012-05-16 11:06 ` Konrad Rzeszutek Wilk
2012-05-03 6:40 ` [PATCH 4/4] zsmalloc: zsmalloc: align cache line size Minchan Kim
2012-05-03 13:58 ` Nitin Gupta
2012-05-04 2:27 ` Minchan Kim
2012-05-07 7:41 ` Pekka Enberg
2012-05-07 12:40 ` Nitin Gupta
2012-05-08 1:34 ` Minchan Kim
2012-05-08 14:00 ` Dan Magenheimer
2012-05-09 0:58 ` Minchan Kim
2012-05-09 3:08 ` Dan Magenheimer
2012-05-09 4:07 ` Minchan Kim
2012-05-11 0:03 ` Dan Magenheimer
2012-05-11 0:25 ` Minchan Kim
2012-05-11 19:06 ` Konrad Rzeszutek Wilk
2012-05-14 1:55 ` Minchan Kim
2012-05-15 15:18 ` Konrad Rzeszutek Wilk
2012-05-16 1:44 ` Minchan Kim
2012-05-03 13:18 ` [PATCH 1/4] zsmalloc: rename zspage_order with zspage_pages Nitin Gupta
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