Re: [PATCH 4/5] mm: zswap: add basic meminfo and vmstat coverage

From: Andrew Morton <akpm@linux-foundation.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>, Roman Gushchin <guro@fb.com>,
	Shakeel Butt <shakeelb@google.com>,
	Seth Jennings <sjenning@redhat.com>,
	Dan Streetman <ddstreet@ieee.org>,
	linux-mm@kvack.org, cgroups@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH 4/5] mm: zswap: add basic meminfo and vmstat coverage
Date: Wed, 27 Apr 2022 11:36:54 -0700	[thread overview]
Message-ID: <20220427113654.ef8f543d7ba279952deff6f7@linux-foundation.org> (raw)
In-Reply-To: <20220427160016.144237-5-hannes@cmpxchg.org>

On Wed, 27 Apr 2022 12:00:15 -0400 Johannes Weiner <hannes@cmpxchg.org> wrote:

> Currently it requires poking at debugfs to figure out the size and
> population of the zswap cache on a host. There are no counters for
> reads and writes against the cache. As a result, it's difficult to
> understand zswap behavior on production systems.
> 
> Print zswap memory consumption and how many pages are zswapped out in
> /proc/meminfo. Count zswapouts and zswapins in /proc/vmstat.

/proc/meminfo is rather prime real estate.  Is this important enough to
be placed in there, or should it instead be in the more lowly
/proc/vmstat?

/proc/meminfo is documented in Documentation/filesystems/proc.rst ;)

That file appears to need a bit of updating for other things.