+ mm-page_ownerc-remove-redudant-drain_all_pages.patch added to mm-unstable branch

+ mm-page_ownerc-remove-redudant-drain_all_pages.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm/page_owner.c: remove redudant drain_all_pages
has been added to the -mm mm-unstable branch.  Its filename is
     mm-page_ownerc-remove-redudant-drain_all_pages.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_ownerc-remove-redudant-drain_all_pages.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Zhenhua Huang <quic_zhenhuah@quicinc.com>
Subject: mm/page_owner.c: remove redudant drain_all_pages
Date: Wed, 7 Sep 2022 16:01:13 +0800

Page owner info of pages in pcp list has already been reset:

	free_unref_page
		-> free_unref_page_prepare
			-> free_pcp_prepare
				-> free_pages_prepare which does page owner
				   reset
		-> free_unref_page_commit which add pages into pcp list

It can also be confirmed from dump that page owner info of pcp pages are
correct.  Hence there is no more need to drain when reading.

Link: https://lkml.kernel.org/r/1662537673-9392-1-git-send-email-quic_zhenhuah@quicinc.com
Signed-off-by: Zhenhua Huang <quic_zhenhuah@quicinc.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_owner.c |    2 --
 1 file changed, 2 deletions(-)

--- a/mm/page_owner.c~mm-page_ownerc-remove-redudant-drain_all_pages
+++ a/mm/page_owner.c
@@ -524,8 +524,6 @@ read_page_owner(struct file *file, char
 	while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
 		pfn++;
 
-	drain_all_pages(NULL);
-
 	/* Find an allocated page */
 	for (; pfn < max_pfn; pfn++) {
 		/*
_

Patches currently in -mm which might be from quic_zhenhuah@quicinc.com are

mm-page_ownerc-remove-redudant-drain_all_pages.patch