Re: [PATCHv2 06/10] zram: remove max_num_devices limitation

[Sergey Senozhatsky]

On (04/23/15 11:36), Minchan Kim wrote:
> Date: Thu, 23 Apr 2015 11:36:36 +0900
> From: Minchan Kim <minchan@xxxxxxxxxx>
> To: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>, Nitin Gupta
>  <ngupta@xxxxxxxxxx>, linux-kernel@xxxxxxxxxxxxxxx, Sergey Senozhatsky
>  <sergey.senozhatsky.work@xxxxxxxxx>
> Subject: Re: [PATCHv2 06/10] zram: remove max_num_devices limitation
> User-Agent: Mutt/1.5.23 (2014-03-12)
> 
> On Thu, Apr 16, 2015 at 08:55:52PM +0900, Sergey Senozhatsky wrote:
> > Limiting the number of zram devices to 32 (default max_num_devices value)
> > is confusing, let's drop it.  A user with 2TB or 4TB of RAM, for example,
> > can request as many devices as he can handle.
> > 
> > Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
> Acked-by: Minchan Kim <minchan@xxxxxxxxxx>
> 
> I don't know you intentionally add new empty lines to make it clear
> below but it's not related to this patch but I'm okay although you
> did it to make to look better. Othewise, please fix when you respin.
> 

no reason. was a bit in a hurry trying to redo the set for 4.1 merge window
and not to miss anything. will clean up.

	-ss

> > ---
> >  Documentation/blockdev/zram.txt | 8 +++++++-
> >  drivers/block/zram/zram_drv.c   | 8 +-------
> >  drivers/block/zram/zram_drv.h   | 6 ------
> >  3 files changed, 8 insertions(+), 14 deletions(-)
> > 
> > diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt
> > index bef4998..2ccc741 100644
> > --- a/Documentation/blockdev/zram.txt
> > +++ b/Documentation/blockdev/zram.txt
> > @@ -19,7 +19,9 @@ Following shows a typical sequence of steps for using zram.
> >  1) Load Module:
> >  	modprobe zram num_devices=4
> >  	This creates 4 devices: /dev/zram{0,1,2,3}
> > -	(num_devices parameter is optional. Default: 1)
> > +
> > +num_devices parameter is optional and tells zram how many devices should be
> > +pre-created. Default: 1.
> >  
> >  2) Set max number of compression streams
> >  	Compression backend may use up to max_comp_streams compression streams,
> > @@ -128,6 +130,7 @@ mem_limit         RW    the maximum amount of memory ZRAM can use to store
> >  num_migrated      RO    the number of objects migrated migrated by compaction
> >  compact           WO    trigger memory compaction
> >  
> > +
> 
> ?
> 
> >  WARNING
> >  =======
> >  per-stat sysfs attributes are considered to be deprecated.
> > @@ -149,6 +152,7 @@ File /sys/block/zram<id>/stat
> >  Represents block layer statistics. Read Documentation/block/stat.txt for
> >  details.
> >  
> > +
> 
> ?
> 
> >  File /sys/block/zram<id>/io_stat
> >  
> >  The stat file represents device's I/O statistics not accounted by block
> > @@ -160,6 +164,7 @@ whitespace:
> >  	invalid_io
> >  	notify_free
> >  
> > +
> 
> ?
> 
> >  File /sys/block/zram<id>/mm_stat
> >  
> >  The stat file represents device's mm statistics. It consists of a single
> > @@ -172,6 +177,7 @@ line of text and contains the following stats separated by whitespace:
> >  	zero_pages
> >  	num_migrated
> >  
> > +
> 
> ?
> 
> >  8) Deactivate:
> >  	swapoff /dev/zram0
> >  	umount /dev/zram1
> > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> > index e526fe1..c2d9b76 100644
> > --- a/drivers/block/zram/zram_drv.c
> > +++ b/drivers/block/zram/zram_drv.c
> > @@ -1288,12 +1288,6 @@ static int __init zram_init(void)
> >  {
> >  	int ret, dev_id;
> >  
> > -	if (num_devices > max_num_devices) {
> > -		pr_warn("Invalid value for num_devices: %u\n",
> > -				num_devices);
> > -		return -EINVAL;
> > -	}
> > -
> >  	zram_major = register_blkdev(0, "zram");
> >  	if (zram_major <= 0) {
> >  		pr_warn("Unable to get major number\n");
> > @@ -1323,7 +1317,7 @@ module_init(zram_init);
> >  module_exit(zram_exit);
> >  
> >  module_param(num_devices, uint, 0);
> > -MODULE_PARM_DESC(num_devices, "Number of zram devices");
> > +MODULE_PARM_DESC(num_devices, "Number of pre-created zram devices");
> >  
> >  MODULE_LICENSE("Dual BSD/GPL");
> >  MODULE_AUTHOR("Nitin Gupta <ngupta@xxxxxxxxxx>");
> > diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
> > index 570c598..042994e 100644
> > --- a/drivers/block/zram/zram_drv.h
> > +++ b/drivers/block/zram/zram_drv.h
> > @@ -20,12 +20,6 @@
> >  
> >  #include "zcomp.h"
> >  
> > -/*
> > - * Some arbitrary value. This is just to catch
> > - * invalid value for num_devices module parameter.
> > - */
> > -static const unsigned max_num_devices = 32;
> > -
> >  /*-- Configurable parameters */
> >  
> >  /*
> > -- 
> > 2.4.0.rc2
> > 
> 
> -- 
> Kind regards,
> Minchan Kim
> 
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