[212/227] Docs/vm/damon/design: update DAMON-Idle Page Tracking interference handling

Commit Message

Andrew Morton March 22, 2022, 9:49 p.m. UTC

From: SeongJae Park <[e-mail]>
Subject: Docs/vm/damon/design: update DAMON-Idle Page Tracking interference handling

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.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: SeongJae Park <[e-mail]>
Cc: Jonathan Corbet <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 Documentation/vm/damon/design.rst |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

Patch

--- a/Documentation/vm/damon/design.rst~docs-vm-damon-design-update-damon-idle-page-tracking-interference-handling
+++ a/Documentation/vm/damon/design.rst
@@ -84,9 +84,10 @@  table having a mapping to the address.
 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