linux-kernel - Re: [PATCH v2] zram: remove double compression logic

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Message-ID: <YnAe52Eg60tjeBNK@google.com>
Date:   Mon, 2 May 2022 11:11:51 -0700
From:   Minchan Kim <minchan@...nel.org>
To:     Aleksey Romanov <AVRomanov@...rdevices.ru>
Cc:     Sergey Senozhatsky <senozhatsky@...omium.org>,
        "ngupta@...are.org" <ngupta@...are.org>,
        "linux-block@...r.kernel.org" <linux-block@...r.kernel.org>,
        "axboe@...omium.org" <axboe@...omium.org>,
        kernel <kernel@...rdevices.ru>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "mnitenko@...il.com" <mnitenko@...il.com>,
        Dmitry Rokosov <DDRokosov@...rdevices.ru>
Subject: Re: [PATCH v2] zram: remove double compression logic

Hi Aleksey,

On Thu, Apr 28, 2022 at 08:01:12PM +0000, Aleksey Romanov wrote:
> Thanks for the reply!
> 
> On Wed, Apr 27, 2022 at 08:30:16PM +0900, Sergey Senozhatsky wrote:
> > On (22/04/27 13:03), Alexey Romanov wrote:
> > > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> > > index cb253d80d72b..4be6caf43b1d 100644
> > > --- a/drivers/block/zram/zram_drv.c
> > > +++ b/drivers/block/zram/zram_drv.c
> > > @@ -1153,9 +1153,8 @@ static ssize_t debug_stat_show(struct device *dev,
> > >  
> > >  	down_read(&zram->init_lock);
> > >  	ret = scnprintf(buf, PAGE_SIZE,
> > > -			"version: %d\n%8llu %8llu\n",
> > > +			"version: %d\n%8llu\n",
> > >  			version,
> > > -			(u64)atomic64_read(&zram->stats.writestall),
> > >  			(u64)atomic64_read(&zram->stats.miss_free));
> > >  	up_read(&zram->init_lock);
> > 
> > I think this also has to bump `version` to 2, since format of the
> > file has changed.
> 
> Yes, I'll do that in the next patch.
> 
> Minchan, do you have any suggestions on this patch? 
> I want to fix Sergey suggestion and sumbit next patch.

You need to remove zs_free in the path "Compression failed"

Since we don't have double compression, we don't need QUEUE_FLAG_STABLE_WRITES
so you could remove QUEUE_FLAG_STABLE_WRITES, too.

Thanks.