Re: [PATCH 0/1] Possible bug in zram on ppc64le on vfat

From: Petr Vorel <pvorel@suse.cz>
To: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>,
	ltp@lists.linux.it, linux-block@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	Nitin Gupta <ngupta@vflare.org>, Jens Axboe <axboe@kernel.dk>,
	OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>,
	Martin Doucha <mdoucha@suse.cz>,
	Yang Xu <xuyang2018.jy@fujitsu.com>
Subject: Re: [PATCH 0/1] Possible bug in zram on ppc64le on vfat
Date: Wed, 9 Nov 2022 23:08:04 +0100	[thread overview]
Message-ID: <Y2wkxBEnbP9jM0h3@pevik> (raw)
In-Reply-To: <Y2mrRxHhVi/QEiUf@google.com>

Hi Sergey, Minchan, all,

> On (22/11/07 23:42), Petr Vorel wrote:
> [..]
> > 15859712        0        0 26214400   196608      242        0
> > zram01 7 TINFO: /sys/block/zram1/mm_stat
> > 15859712        0        0 26214400   196608      242        0
> > zram01 7 TINFO: /sys/block/zram1/mm_stat
> > 15859712        0        0 26214400   196608      242        0
> > zram01 7 TINFO: /sys/block/zram1/mm_stat
> > 15859712        0        0 26214400   196608      242        0
> > zram01 7 TINFO: /sys/block/zram1/mm_stat
> > 15859712        0        0 26214400   196608      242        0
> > zram01 7 TINFO: /sys/block/zram1/mm_stat
> > 15859712        0        0 26214400   196608      242        0
> > zram01 7 TINFO: /sys/block/zram1/mm_stat
> > 15859712        0        0 26214400   196608      242        0
> > zram01 7 TBROK: "loop_read_mem_used_total /sys/block/zram1/mm_stat" timed out

> Looking at mm_stat_show(), mem_used can be 0 when mm_stat_show() is
> called on un-initialized device

> ---
> ...
>         u64 orig_size, mem_used = 0;
>         long max_used;
>         ssize_t ret;

>         memset(&pool_stats, 0x00, sizeof(struct zs_pool_stats));

>         down_read(&zram->init_lock);
>         if (init_done(zram)) {
>                 mem_used = zs_get_total_pages(zram->mem_pool);
>                 zs_pool_stats(zram->mem_pool, &pool_stats);
>         }
> ...
> ---

> Can you check if init_done() returns true in your tests?

I'm sorry, it took me some time to find machine where I'd be compile kernel.
Yes, init_done() returns non-zero (1), code goes into if clause and sets
mem_used. I'll check also for mem_used value.

Kind regards,
Petr