Skip to main content

Browse the archive

https://github.com/torvalds/linux
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
Makefile.modinst 
# SPDX-License-Identifier: GPL-2.0
# ==========================================================================
# Installing modules
# ==========================================================================

PHONY := __modinst
__modinst:

include include/config/auto.conf
include $(srctree)/scripts/Kbuild.include

modules := $(sort $(shell cat $(MODORDER)))

ifeq ($(KBUILD_EXTMOD),)
dst := $(MODLIB)/kernel
else
INSTALL_MOD_DIR ?= extra
dst := $(MODLIB)/$(INSTALL_MOD_DIR)
endif

suffix-y				:=
suffix-$(CONFIG_MODULE_COMPRESS_GZIP)	:= .gz
suffix-$(CONFIG_MODULE_COMPRESS_XZ)	:= .xz
suffix-$(CONFIG_MODULE_COMPRESS_ZSTD)	:= .zst

modules := $(patsubst $(extmod_prefix)%, $(dst)/%$(suffix-y), $(modules))

__modinst: $(modules)
	@:

quiet_cmd_none =
      cmd_none = :

#
# Installation
#
quiet_cmd_install = INSTALL $@
      cmd_install = mkdir -p $(dir $@); cp $< $@

# Strip
#
# INSTALL_MOD_STRIP, if defined, will cause modules to be stripped after they
# are installed. If INSTALL_MOD_STRIP is '1', then the default option
# --strip-debug will be used. Otherwise, INSTALL_MOD_STRIP value will be used
# as the options to the strip command.
ifdef INSTALL_MOD_STRIP

ifeq ($(INSTALL_MOD_STRIP),1)
strip-option := --strip-debug
else
strip-option := $(INSTALL_MOD_STRIP)
endif

quiet_cmd_strip = STRIP   $@
      cmd_strip = $(STRIP) $(strip-option) $@

else

quiet_cmd_strip =
      cmd_strip = :

endif

#
# Signing
# Don't stop modules_install even if we can't sign external modules.
#
ifeq ($(CONFIG_MODULE_SIG_ALL),y)
sig-key := $(if $(wildcard $(CONFIG_MODULE_SIG_KEY)),,$(srctree)/)$(CONFIG_MODULE_SIG_KEY)
quiet_cmd_sign = SIGN    $@
      cmd_sign = scripts/sign-file $(CONFIG_MODULE_SIG_HASH) $(sig-key) certs/signing_key.x509 $@ \
                 $(if $(KBUILD_EXTMOD),|| true)
else
quiet_cmd_sign :=
      cmd_sign := :
endif

ifeq ($(modules_sign_only),)

$(dst)/%.ko: $(extmod_prefix)%.ko FORCE
	$(call cmd,install)
	$(call cmd,strip)
	$(call cmd,sign)

else

$(dst)/%.ko: FORCE
	$(call cmd,sign)

endif

#
# Compression
#
quiet_cmd_gzip = GZIP    $@
      cmd_gzip = $(KGZIP) -n -f $<
quiet_cmd_xz = XZ      $@
      cmd_xz = $(XZ) --lzma2=dict=2MiB -f $<
quiet_cmd_zstd = ZSTD    $@
      cmd_zstd = $(ZSTD) -T0 --rm -f -q $<

$(dst)/%.ko.gz: $(dst)/%.ko FORCE
	$(call cmd,gzip)

$(dst)/%.ko.xz: $(dst)/%.ko FORCE
	$(call cmd,xz)

$(dst)/%.ko.zst: $(dst)/%.ko FORCE
	$(call cmd,zstd)

PHONY += FORCE
FORCE:

.PHONY: $(PHONY)
back to top