Commit 118642d7 authored Feb 13, 2024 by Johannes Weiner Committed by Andrew Morton Feb 20, 2024

mm: memcontrol: clarify swapaccount=0 deprecation warning

The swapaccount deprecation warning is throwing false positives.  Since we
deprecated the knob and defaulted to enabling, the only reports we've been
getting are from folks that set swapaccount=1.  While this is a nice
affirmation that always-enabling was the right choice, we certainly don't
want to warn when users request the supported mode.

Only warn when disabling is requested, and clarify the warning.

[colin.i.king@gmail.com: spelling: "commdandline" -> "commandline"]
  Link: https://lkml.kernel.org/r/20240215090544.1649201-1-colin.i.king@gmail.com
Link: https://lkml.kernel.org/r/20240213081634.3652326-1-hannes@cmpxchg.org


Fixes: b25806dc ("mm: memcontrol: deprecate swapaccounting=0 mode")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reported-by: "Jonas Schäfer" <jonas@wielicki.name>
Reported-by: Narcis Garcia <debianlists@actiu.net>
Suggested-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

parent 4f155af0

mm/memcontrol.c

+7 −3

Original line number	Diff line number	Diff line
		@@ -7971,7 +7971,11 @@ bool mem_cgroup_swap_full(struct folio *folio)

		static int __init setup_swap_account(char *s)
		{
		pr_warn_once("The swapaccount= commandline option is deprecated. "
		bool res;

		if (!kstrtobool(s, &res) && !res)
		pr_warn_once("The swapaccount=0 commandline option is deprecated "
		"in favor of configuring swap control via cgroupfs. "
		"Please report your usecase to linux-mm@kvack.org if you "
		"depend on this functionality.\n");
		return 1;