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Date: Tue, 25 Jul 2017 13:42:47 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Johannes Weiner <hannes@cmpxchg.org>, Minchan Kim <minchan@kernel.org>,
        Rik van Riel <riel@redhat.com>, Shaohua Li <shli@kernel.org>,
        Hugh Dickins <hughd@google.com>, Fengguang Wu <fengguang.wu@intel.com>,
        Tim Chen <tim.c.chen@intel.com>, Dave Hansen <dave.hansen@intel.com>
Subject: Re: [PATCH -mm -v3 1/6] mm, swap: Add swap cache statistics sysfs
 interface
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On Tue, 25 Jul 2017 09:51:46 +0800 "Huang, Ying" <ying.huang@intel.com> wrote:

> The swap cache stats could be gotten only via sysrq, which isn't
> convenient in some situation.  So the sysfs interface of swap cache
> stats is added for that.  The added sysfs directories/files are as
> follow,
> 
> /sys/kernel/mm/swap
> /sys/kernel/mm/swap/cache_find_total
> /sys/kernel/mm/swap/cache_find_success
> /sys/kernel/mm/swap/cache_add
> /sys/kernel/mm/swap/cache_del
> /sys/kernel/mm/swap/cache_pages

We should document this somewhere.  Documentation/ABI/ is the formal
place for sysfs files, but nobody will think to look there for VM
things, so perhaps place a pointer to the Documentation/ABI/ files
within Documentation/vm somewhere, only there isn't an appropriate
Documentation/vm file ;)

Or just put all these things in debugfs.  These are pretty specialized
things and appear to be developer-only files of short-term interest?