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05 April 2024, 19:05:47 UTC
Revision 9282012fc0aa248b77a69f5eb802b67c5a16bb13 authored by Jaewon Kim on 25 July 2022, 09:52:12 UTC, committed by Andrew Morton on 29 July 2022, 18:33:37 UTC 
page_alloc: fix invalid watermark check on a negative value
 
There was a report that a task is waiting at the
throttle_direct_reclaim. The pgscan_direct_throttle in vmstat was
increasing.

This is a bug where zone_watermark_fast returns true even when the free
is very low. The commit f27ce0e14088 ("page_alloc: consider highatomic
reserve in watermark fast") changed the watermark fast to consider
highatomic reserve. But it did not handle a negative value case which
can be happened when reserved_highatomic pageblock is bigger than the
actual free.

If watermark is considered as ok for the negative value, allocating
contexts for order-0 will consume all free pages without direct reclaim,
and finally free page may become depleted except highatomic free.

Then allocating contexts may fall into throttle_direct_reclaim. This
symptom may easily happen in a system where wmark min is low and other
reclaimers like kswapd does not make free pages quickly.

Handle the negative case by using MIN.

Link: https://lkml.kernel.org/r/20220725095212.25388-1-jaewon31.kim@samsung.com
Fixes: f27ce0e14088 ("page_alloc: consider highatomic reserve in watermark fast")
Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com>
Reported-by: GyeongHwan Hong <gh21.hong@samsung.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Yong-Taek Lee <ytk.lee@samsung.com>
Cc: <stable@vger.kerenl.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
1 parent 1f7ea54
Raw File
Tip revision: 9282012fc0aa248b77a69f5eb802b67c5a16bb13 authored by Jaewon Kim on 25 July 2022, 09:52:12 UTC
page_alloc: fix invalid watermark check on a negative value
Tip revision: 9282012
install.sh 
#!/bin/sh
# SPDX-License-Identifier: GPL-2.0-only
#
# Copyright (C) 1995 by Linus Torvalds
#
# Adapted from code in arch/i386/boot/Makefile by H. Peter Anvin
# Common code factored out by Masahiro Yamada

set -e

# Make sure the files actually exist
for file in "${KBUILD_IMAGE}" System.map
do
	if [ ! -f "${file}" ]; then
		echo >&2
		echo >&2 " *** Missing file: ${file}"
		echo >&2 ' *** You need to run "make" before "make install".'
		echo >&2
		exit 1
	fi
done

# User/arch may have a custom install script
for file in "${HOME}/bin/${INSTALLKERNEL}"		\
	    "/sbin/${INSTALLKERNEL}"			\
	    "${srctree}/arch/${SRCARCH}/install.sh"	\
	    "${srctree}/arch/${SRCARCH}/boot/install.sh"
do
	if [ ! -x "${file}" ]; then
		continue
	fi

	# installkernel(8) says the parameters are like follows:
	#
	#   installkernel version zImage System.map [directory]
	exec "${file}" "${KERNELRELEASE}" "${KBUILD_IMAGE}" System.map "${INSTALL_PATH}"
done

echo "No install script found" >&2
exit 1
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