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From:   SeongJae Park <sj@kernel.org>
To:     akpm@linux-foundation.org
Cc:     corbet@lwn.net, linux-mm@kvack.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, SeongJae Park <sj@kernel.org>
Subject: [PATCH 2/3] Docs/vm/damon/design: Update DAMON-Idle Page Tracking interference handling
Date:   Tue, 22 Feb 2022 17:00:59 +0000
Message-Id: <20220222170100.17068-3-sj@kernel.org>
In-Reply-To: <20220222170100.17068-1-sj@kernel.org>
References: <20220222170100.17068-1-sj@kernel.org>
Precedence: bulk

In DAMON's early development stage before it be merged in the mainline,
it was first designed to work exclusively with Idle page tracking to
avoid any interference between each other.  Later, but still before
be merged in the mainline, because Idle page tracking is fully under the
control of sysadmins, we made the resolving of conflict as the
responsibility of sysadmins.  The document is not updated for the
change, though.  This commit updates the document for that.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/vm/damon/design.rst | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/Documentation/vm/damon/design.rst b/Documentation/vm/damon/design.rst
index c406983aeb31..bba89632e924 100644
--- a/Documentation/vm/damon/design.rst
+++ b/Documentation/vm/damon/design.rst
@@ -84,9 +84,10 @@ table having a mapping to the address.  In this way, the implementations find
 and clear the bit(s) for next sampling target address and checks whether the
 bit(s) set again after one sampling period.  This could disturb other kernel
 subsystems using the Accessed bits, namely Idle page tracking and the reclaim
-logic.  To avoid such disturbances, DAMON makes it mutually exclusive with Idle
-page tracking and uses ``PG_idle`` and ``PG_young`` page flags to solve the
-conflict with the reclaim logic, as Idle page tracking does.
+logic.  DAMON does nothing to avoid disturbing Idle page tracking, so handling
+the interference is the responsibility of sysadmins.  However, it solves the
+conflict with the reclaim logic using ``PG_idle`` and ``PG_young`` page flags,
+as Idle page tracking does.
 
 
 Address Space Independent Core Mechanisms
-- 
2.17.1