linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH v3 0/8] mm/memory_hotplug: allow to specify a default online_type
@ 2020-03-19 13:12 David Hildenbrand
  2020-03-19 13:12 ` [PATCH v3 1/8] drivers/base/memory: rename MMOP_ONLINE_KEEP to MMOP_ONLINE David Hildenbrand
                   ` (8 more replies)
  0 siblings, 9 replies; 19+ messages in thread
From: David Hildenbrand @ 2020-03-19 13:12 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-mm, linuxppc-dev, linux-hyperv, David Hildenbrand,
	Vitaly Kuznetsov, Yumei Huang, Igor Mammedov, Baoquan He,
	Eduardo Habkost, Milan Zamazal, Andrew Morton,
	Benjamin Herrenschmidt, Greg Kroah-Hartman, Haiyang Zhang,
	K. Y. Srinivasan, Michael Ellerman, Michal Hocko, Michal Hocko,
	Oscar Salvador, Paul Mackerras, Rafael J. Wysocki,
	Stephen Hemminger, Wei Liu, Wei Yang

Distributions nowadays use udev rules ([1] [2]) to specify if and
how to online hotplugged memory. The rules seem to get more complex with
many special cases. Due to the various special cases,
CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE cannot be used. All memory hotplug
is handled via udev rules.

Everytime we hotplug memory, the udev rule will come to the same
conclusion. Especially Hyper-V (but also soon virtio-mem) add a lot of
memory in separate memory blocks and wait for memory to get onlined by user
space before continuing to add more memory blocks (to not add memory faster
than it is getting onlined). This of course slows down the whole memory
hotplug process.

To make the job of distributions easier and to avoid udev rules that get
more and more complicated, let's extend the mechanism provided by
- /sys/devices/system/memory/auto_online_blocks
- "memhp_default_state=" on the kernel cmdline
to be able to specify also "online_movable" as well as "online_kernel"

v2 -> v3:
- "hv_balloon: don't check for memhp_auto_online manually"
-- init_completion() before register_memory_notifier()
- Minor typo fix

v1 -> v2:
- Tweaked some patch descriptions
- Added
-- "powernv/memtrace: always online added memory blocks"
-- "hv_balloon: don't check for memhp_auto_online manually"
-- "mm/memory_hotplug: unexport memhp_auto_online"
- "mm/memory_hotplug: convert memhp_auto_online to store an online_type"
-- No longer touches hv/memtrace code


=== Example /usr/libexec/config-memhotplug ===

#!/bin/bash

VIRT=`systemd-detect-virt --vm`
ARCH=`uname -p`

sense_virtio_mem() {
  if [ -d "/sys/bus/virtio/drivers/virtio_mem/" ]; then
    DEVICES=`find /sys/bus/virtio/drivers/virtio_mem/ -maxdepth 1 -type l | wc -l`
    if [ $DEVICES != "0" ]; then
        return 0
    fi
  fi
  return 1
}

if [ ! -e "/sys/devices/system/memory/auto_online_blocks" ]; then
  echo "Memory hotplug configuration support missing in the kernel"
  exit 1
fi

if grep "memhp_default_state=" /proc/cmdline > /dev/null; then
  echo "Memory hotplug configuration overridden in kernel cmdline (memhp_default_state=)"
  exit 1
fi

if [ $VIRT == "microsoft" ]; then
  echo "Detected Hyper-V on $ARCH"
  # Hyper-V wants all memory in ZONE_NORMAL
  ONLINE_TYPE="online_kernel"
elif sense_virtio_mem; then
  echo "Detected virtio-mem on $ARCH"
  # virtio-mem wants all memory in ZONE_NORMAL
  ONLINE_TYPE="online_kernel"
elif [ $ARCH == "s390x" ] || [ $ARCH == "s390" ]; then
  echo "Detected $ARCH"
  # standby memory should not be onlined automatically
  ONLINE_TYPE="offline"
elif [ $ARCH == "ppc64" ] || [ $ARCH == "ppc64le" ]; then
  echo "Detected" $ARCH
  # PPC64 onlines all hotplugged memory right from the kernel
  ONLINE_TYPE="offline"
elif [ $VIRT == "none" ]; then
  echo "Detected bare-metal on $ARCH"
  # Bare metal users expect hotplugged memory to be unpluggable. We assume
  # that ZONE imbalances on such enterpise servers cannot happen and is
  # properly documented
  ONLINE_TYPE="online_movable"
else
  # TODO: Hypervisors that want to unplug DIMMs and can guarantee that ZONE
  # imbalances won't happen
  echo "Detected $VIRT on $ARCH"
  # Usually, ballooning is used in virtual environments, so memory should go to
  # ZONE_NORMAL. However, sometimes "movable_node" is relevant.
  ONLINE_TYPE="online"
fi

echo "Selected online_type:" $ONLINE_TYPE

# Configure what to do with memory that will be hotplugged in the future
echo $ONLINE_TYPE 2>/dev/null > /sys/devices/system/memory/auto_online_blocks
if [ $? != "0" ]; then
  echo "Memory hotplug cannot be configured (e.g., old kernel or missing permissions)"
  # A backup udev rule should handle old kernels if necessary
  exit 1
fi

# Process all already pluggedd blocks (e.g., DIMMs, but also Hyper-V or virtio-mem)
if [ $ONLINE_TYPE != "offline" ]; then
  for MEMORY in /sys/devices/system/memory/memory*; do
    STATE=`cat $MEMORY/state`
    if [ $STATE == "offline" ]; then
        echo $ONLINE_TYPE > $MEMORY/state
    fi
  done
fi


=== Example /usr/lib/systemd/system/config-memhotplug.service ===

[Unit]
Description=Configure memory hotplug behavior
DefaultDependencies=no
Conflicts=shutdown.target
Before=sysinit.target shutdown.target
After=systemd-modules-load.service
ConditionPathExists=|/sys/devices/system/memory/auto_online_blocks

[Service]
ExecStart=/usr/libexec/config-memhotplug
Type=oneshot
TimeoutSec=0
RemainAfterExit=yes

[Install]
WantedBy=sysinit.target


=== Example modification to the 40-redhat.rules [2] ===

diff --git a/40-redhat.rules b/40-redhat.rules-new
index 2c690e5..168fd03 100644
--- a/40-redhat.rules
+++ b/40-redhat.rules-new
@@ -6,6 +6,9 @@ SUBSYSTEM=="cpu", ACTION=="add", TEST=="online", ATTR{online}=="0", ATTR{online}
 # Memory hotadd request
 SUBSYSTEM!="memory", GOTO="memory_hotplug_end"
 ACTION!="add", GOTO="memory_hotplug_end"
+# memory hotplug behavior configured
+PROGRAM=="grep online /sys/devices/system/memory/auto_online_blocks", GOTO="memory_hotplug_end"
+
 PROGRAM="/bin/uname -p", RESULT=="s390*", GOTO="memory_hotplug_end"

 ENV{.state}="online"

===


[1] https://github.com/lnykryn/systemd-rhel/pull/281
[2] https://github.com/lnykryn/systemd-rhel/blob/staging/rules/40-redhat.rules

Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Yumei Huang <yuhuang@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Milan Zamazal <mzamazal@redhat.com>

David Hildenbrand (8):
  drivers/base/memory: rename MMOP_ONLINE_KEEP to MMOP_ONLINE
  drivers/base/memory: map MMOP_OFFLINE to 0
  drivers/base/memory: store mapping between MMOP_* and string in an
    array
  powernv/memtrace: always online added memory blocks
  hv_balloon: don't check for memhp_auto_online manually
  mm/memory_hotplug: unexport memhp_auto_online
  mm/memory_hotplug: convert memhp_auto_online to store an online_type
  mm/memory_hotplug: allow to specify a default online_type

 arch/powerpc/platforms/powernv/memtrace.c | 14 ++---
 drivers/base/memory.c                     | 71 ++++++++++++-----------
 drivers/hv/hv_balloon.c                   | 25 ++++----
 include/linux/memory_hotplug.h            | 13 ++++-
 mm/memory_hotplug.c                       | 16 ++---
 5 files changed, 69 insertions(+), 70 deletions(-)

-- 
2.24.1


^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [PATCH v3 1/8] drivers/base/memory: rename MMOP_ONLINE_KEEP to MMOP_ONLINE
  2020-03-19 13:12 [PATCH v3 0/8] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
@ 2020-03-19 13:12 ` David Hildenbrand
  2020-03-19 16:28   ` Pankaj Gupta
  2020-03-19 13:12 ` [PATCH v3 2/8] drivers/base/memory: map MMOP_OFFLINE to 0 David Hildenbrand
                   ` (7 subsequent siblings)
  8 siblings, 1 reply; 19+ messages in thread
From: David Hildenbrand @ 2020-03-19 13:12 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-mm, linuxppc-dev, linux-hyperv, David Hildenbrand,
	Wei Yang, Greg Kroah-Hartman, Andrew Morton, Michal Hocko,
	Oscar Salvador, Rafael J. Wysocki, Baoquan He

The name is misleading and it's not really clear what is "kept". Let's just
name it like the online_type name we expose to user space ("online").

Add some documentation to the types.

Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 drivers/base/memory.c          | 9 +++++----
 include/linux/memory_hotplug.h | 6 +++++-
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 6448c9ece2cb..8c5ce42c0fc3 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -216,7 +216,7 @@ static int memory_subsys_online(struct device *dev)
 	 * attribute and need to set the online_type.
 	 */
 	if (mem->online_type < 0)
-		mem->online_type = MMOP_ONLINE_KEEP;
+		mem->online_type = MMOP_ONLINE;
 
 	ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
 
@@ -251,7 +251,7 @@ static ssize_t state_store(struct device *dev, struct device_attribute *attr,
 	else if (sysfs_streq(buf, "online_movable"))
 		online_type = MMOP_ONLINE_MOVABLE;
 	else if (sysfs_streq(buf, "online"))
-		online_type = MMOP_ONLINE_KEEP;
+		online_type = MMOP_ONLINE;
 	else if (sysfs_streq(buf, "offline"))
 		online_type = MMOP_OFFLINE;
 	else {
@@ -262,7 +262,7 @@ static ssize_t state_store(struct device *dev, struct device_attribute *attr,
 	switch (online_type) {
 	case MMOP_ONLINE_KERNEL:
 	case MMOP_ONLINE_MOVABLE:
-	case MMOP_ONLINE_KEEP:
+	case MMOP_ONLINE:
 		/* mem->online_type is protected by device_hotplug_lock */
 		mem->online_type = online_type;
 		ret = device_online(&mem->dev);
@@ -342,7 +342,8 @@ static ssize_t valid_zones_show(struct device *dev,
 	}
 
 	nid = mem->nid;
-	default_zone = zone_for_pfn_range(MMOP_ONLINE_KEEP, nid, start_pfn, nr_pages);
+	default_zone = zone_for_pfn_range(MMOP_ONLINE, nid, start_pfn,
+					  nr_pages);
 	strcat(buf, default_zone->name);
 
 	print_allowed_zone(buf, nid, start_pfn, nr_pages, MMOP_ONLINE_KERNEL,
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 3195d11876ea..3aaf00db224c 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -47,9 +47,13 @@ enum {
 
 /* Types for control the zone type of onlined and offlined memory */
 enum {
+	/* Offline the memory. */
 	MMOP_OFFLINE = -1,
-	MMOP_ONLINE_KEEP,
+	/* Online the memory. Zone depends, see default_zone_for_pfn(). */
+	MMOP_ONLINE,
+	/* Online the memory to ZONE_NORMAL. */
 	MMOP_ONLINE_KERNEL,
+	/* Online the memory to ZONE_MOVABLE. */
 	MMOP_ONLINE_MOVABLE,
 };
 
-- 
2.24.1


^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [PATCH v3 2/8] drivers/base/memory: map MMOP_OFFLINE to 0
  2020-03-19 13:12 [PATCH v3 0/8] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
  2020-03-19 13:12 ` [PATCH v3 1/8] drivers/base/memory: rename MMOP_ONLINE_KEEP to MMOP_ONLINE David Hildenbrand
@ 2020-03-19 13:12 ` David Hildenbrand
  2020-03-19 16:29   ` Pankaj Gupta
  2020-03-19 13:12 ` [PATCH v3 3/8] drivers/base/memory: store mapping between MMOP_* and string in an array David Hildenbrand
                   ` (6 subsequent siblings)
  8 siblings, 1 reply; 19+ messages in thread
From: David Hildenbrand @ 2020-03-19 13:12 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-mm, linuxppc-dev, linux-hyperv, David Hildenbrand,
	Wei Yang, Michal Hocko, Greg Kroah-Hartman, Andrew Morton,
	Michal Hocko, Oscar Salvador, Rafael J. Wysocki, Baoquan He

Historically, we used the value -1. Just treat 0 as the special
case now. Clarify a comment (which was wrong, when we come via
device_online() the first time, the online_type would have been 0 /
MEM_ONLINE). The default is now always MMOP_OFFLINE. This removes the
last user of the manual "-1", which didn't use the enum value.

This is a preparation to use the online_type as an array index.

Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 drivers/base/memory.c          | 11 ++++-------
 include/linux/memory_hotplug.h |  2 +-
 2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 8c5ce42c0fc3..e7e77cafef80 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -211,17 +211,14 @@ static int memory_subsys_online(struct device *dev)
 		return 0;
 
 	/*
-	 * If we are called from state_store(), online_type will be
-	 * set >= 0 Otherwise we were called from the device online
-	 * attribute and need to set the online_type.
+	 * When called via device_online() without configuring the online_type,
+	 * we want to default to MMOP_ONLINE.
 	 */
-	if (mem->online_type < 0)
+	if (mem->online_type == MMOP_OFFLINE)
 		mem->online_type = MMOP_ONLINE;
 
 	ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
-
-	/* clear online_type */
-	mem->online_type = -1;
+	mem->online_type = MMOP_OFFLINE;
 
 	return ret;
 }
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 3aaf00db224c..76f3c617a8ab 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -48,7 +48,7 @@ enum {
 /* Types for control the zone type of onlined and offlined memory */
 enum {
 	/* Offline the memory. */
-	MMOP_OFFLINE = -1,
+	MMOP_OFFLINE = 0,
 	/* Online the memory. Zone depends, see default_zone_for_pfn(). */
 	MMOP_ONLINE,
 	/* Online the memory to ZONE_NORMAL. */
-- 
2.24.1


^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [PATCH v3 3/8] drivers/base/memory: store mapping between MMOP_* and string in an array
  2020-03-19 13:12 [PATCH v3 0/8] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
  2020-03-19 13:12 ` [PATCH v3 1/8] drivers/base/memory: rename MMOP_ONLINE_KEEP to MMOP_ONLINE David Hildenbrand
  2020-03-19 13:12 ` [PATCH v3 2/8] drivers/base/memory: map MMOP_OFFLINE to 0 David Hildenbrand
@ 2020-03-19 13:12 ` David Hildenbrand
  2020-03-19 16:33   ` Pankaj Gupta
  2020-03-20  7:36   ` Baoquan He
  2020-03-19 13:12 ` [PATCH v3 4/8] powernv/memtrace: always online added memory blocks David Hildenbrand
                   ` (5 subsequent siblings)
  8 siblings, 2 replies; 19+ messages in thread
From: David Hildenbrand @ 2020-03-19 13:12 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-mm, linuxppc-dev, linux-hyperv, David Hildenbrand,
	Wei Yang, Michal Hocko, Greg Kroah-Hartman, Andrew Morton,
	Michal Hocko, Oscar Salvador, Rafael J. Wysocki, Baoquan He

Let's use a simple array which we can reuse soon. While at it, move the
string->mmop conversion out of the device hotplug lock.

Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 drivers/base/memory.c | 38 +++++++++++++++++++++++---------------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index e7e77cafef80..8a7f29c0bf97 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -28,6 +28,24 @@
 
 #define MEMORY_CLASS_NAME	"memory"
 
+static const char *const online_type_to_str[] = {
+	[MMOP_OFFLINE] = "offline",
+	[MMOP_ONLINE] = "online",
+	[MMOP_ONLINE_KERNEL] = "online_kernel",
+	[MMOP_ONLINE_MOVABLE] = "online_movable",
+};
+
+static int memhp_online_type_from_str(const char *str)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(online_type_to_str); i++) {
+		if (sysfs_streq(str, online_type_to_str[i]))
+			return i;
+	}
+	return -EINVAL;
+}
+
 #define to_memory_block(dev) container_of(dev, struct memory_block, dev)
 
 static int sections_per_block;
@@ -236,26 +254,17 @@ static int memory_subsys_offline(struct device *dev)
 static ssize_t state_store(struct device *dev, struct device_attribute *attr,
 			   const char *buf, size_t count)
 {
+	const int online_type = memhp_online_type_from_str(buf);
 	struct memory_block *mem = to_memory_block(dev);
-	int ret, online_type;
+	int ret;
+
+	if (online_type < 0)
+		return -EINVAL;
 
 	ret = lock_device_hotplug_sysfs();
 	if (ret)
 		return ret;
 
-	if (sysfs_streq(buf, "online_kernel"))
-		online_type = MMOP_ONLINE_KERNEL;
-	else if (sysfs_streq(buf, "online_movable"))
-		online_type = MMOP_ONLINE_MOVABLE;
-	else if (sysfs_streq(buf, "online"))
-		online_type = MMOP_ONLINE;
-	else if (sysfs_streq(buf, "offline"))
-		online_type = MMOP_OFFLINE;
-	else {
-		ret = -EINVAL;
-		goto err;
-	}
-
 	switch (online_type) {
 	case MMOP_ONLINE_KERNEL:
 	case MMOP_ONLINE_MOVABLE:
@@ -271,7 +280,6 @@ static ssize_t state_store(struct device *dev, struct device_attribute *attr,
 		ret = -EINVAL; /* should never happen */
 	}
 
-err:
 	unlock_device_hotplug();
 
 	if (ret < 0)
-- 
2.24.1


^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [PATCH v3 4/8] powernv/memtrace: always online added memory blocks
  2020-03-19 13:12 [PATCH v3 0/8] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
                   ` (2 preceding siblings ...)
  2020-03-19 13:12 ` [PATCH v3 3/8] drivers/base/memory: store mapping between MMOP_* and string in an array David Hildenbrand
@ 2020-03-19 13:12 ` David Hildenbrand
  2020-03-19 13:12 ` [PATCH v3 5/8] hv_balloon: don't check for memhp_auto_online manually David Hildenbrand
                   ` (4 subsequent siblings)
  8 siblings, 0 replies; 19+ messages in thread
From: David Hildenbrand @ 2020-03-19 13:12 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-mm, linuxppc-dev, linux-hyperv, David Hildenbrand,
	Wei Yang, Michal Hocko, Michael Ellerman, Benjamin Herrenschmidt,
	Paul Mackerras, Andrew Morton, Greg Kroah-Hartman, Michal Hocko,
	Oscar Salvador, Rafael J. Wysocki, Baoquan He

Let's always try to online the re-added memory blocks. In case add_memory()
already onlined the added memory blocks, the first device_online() call
will fail and stop processing the remaining memory blocks.

This avoids manually having to check memhp_auto_online.

Note: PPC always onlines all hotplugged memory directly from the kernel
as well - something that is handled by user space on other
architectures.

Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 arch/powerpc/platforms/powernv/memtrace.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
index d6d64f8718e6..13b369d2cc45 100644
--- a/arch/powerpc/platforms/powernv/memtrace.c
+++ b/arch/powerpc/platforms/powernv/memtrace.c
@@ -231,16 +231,10 @@ static int memtrace_online(void)
 			continue;
 		}
 
-		/*
-		 * If kernel isn't compiled with the auto online option
-		 * we need to online the memory ourselves.
-		 */
-		if (!memhp_auto_online) {
-			lock_device_hotplug();
-			walk_memory_blocks(ent->start, ent->size, NULL,
-					   online_mem_block);
-			unlock_device_hotplug();
-		}
+		lock_device_hotplug();
+		walk_memory_blocks(ent->start, ent->size, NULL,
+				   online_mem_block);
+		unlock_device_hotplug();
 
 		/*
 		 * Memory was added successfully so clean up references to it
-- 
2.24.1


^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [PATCH v3 5/8] hv_balloon: don't check for memhp_auto_online manually
  2020-03-19 13:12 [PATCH v3 0/8] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
                   ` (3 preceding siblings ...)
  2020-03-19 13:12 ` [PATCH v3 4/8] powernv/memtrace: always online added memory blocks David Hildenbrand
@ 2020-03-19 13:12 ` David Hildenbrand
  2020-03-19 13:12 ` [PATCH v3 6/8] mm/memory_hotplug: unexport memhp_auto_online David Hildenbrand
                   ` (3 subsequent siblings)
  8 siblings, 0 replies; 19+ messages in thread
From: David Hildenbrand @ 2020-03-19 13:12 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-mm, linuxppc-dev, linux-hyperv, David Hildenbrand,
	Vitaly Kuznetsov, K. Y. Srinivasan, Haiyang Zhang,
	Stephen Hemminger, Wei Liu, Andrew Morton, Michal Hocko,
	Oscar Salvador, Rafael J. Wysocki, Baoquan He, Wei Yang

We get the MEM_ONLINE notifier call if memory is added right from the
kernel via add_memory() or later from user space.

Let's get rid of the "ha_waiting" flag - the wait event has an inbuilt
mechanism (->done) for that. Initialize the wait event only once and
reinitialize before adding memory. Unconditionally call complete() and
wait_for_completion_timeout().

If there are no waiters, complete() will only increment ->done - which
will be reset by reinit_completion(). If complete() has already been
called, wait_for_completion_timeout() will not wait.

There is still the chance for a small race between concurrent
reinit_completion() and complete(). If complete() wins, we would not
wait - which is tolerable (and the race exists in current code as well).

Note: We only wait for "some" memory to get onlined, which seems to be
      good enough for now.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: linux-hyperv@vger.kernel.org
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 drivers/hv/hv_balloon.c | 25 ++++++++++---------------
 1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index a02ce43d778d..32e3bc0aa665 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -533,7 +533,6 @@ struct hv_dynmem_device {
 	 * State to synchronize hot-add.
 	 */
 	struct completion  ol_waitevent;
-	bool ha_waiting;
 	/*
 	 * This thread handles hot-add
 	 * requests from the host as well as notifying
@@ -634,10 +633,7 @@ static int hv_memory_notifier(struct notifier_block *nb, unsigned long val,
 	switch (val) {
 	case MEM_ONLINE:
 	case MEM_CANCEL_ONLINE:
-		if (dm_device.ha_waiting) {
-			dm_device.ha_waiting = false;
-			complete(&dm_device.ol_waitevent);
-		}
+		complete(&dm_device.ol_waitevent);
 		break;
 
 	case MEM_OFFLINE:
@@ -726,8 +722,7 @@ static void hv_mem_hot_add(unsigned long start, unsigned long size,
 		has->covered_end_pfn +=  processed_pfn;
 		spin_unlock_irqrestore(&dm_device.ha_lock, flags);
 
-		init_completion(&dm_device.ol_waitevent);
-		dm_device.ha_waiting = !memhp_auto_online;
+		reinit_completion(&dm_device.ol_waitevent);
 
 		nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn));
 		ret = add_memory(nid, PFN_PHYS((start_pfn)),
@@ -753,15 +748,14 @@ static void hv_mem_hot_add(unsigned long start, unsigned long size,
 		}
 
 		/*
-		 * Wait for the memory block to be onlined when memory onlining
-		 * is done outside of kernel (memhp_auto_online). Since the hot
-		 * add has succeeded, it is ok to proceed even if the pages in
-		 * the hot added region have not been "onlined" within the
-		 * allowed time.
+		 * Wait for memory to get onlined. If the kernel onlined the
+		 * memory when adding it, this will return directly. Otherwise,
+		 * it will wait for user space to online the memory. This helps
+		 * to avoid adding memory faster than it is getting onlined. As
+		 * adding succeeded, it is ok to proceed even if the memory was
+		 * not onlined in time.
 		 */
-		if (dm_device.ha_waiting)
-			wait_for_completion_timeout(&dm_device.ol_waitevent,
-						    5*HZ);
+		wait_for_completion_timeout(&dm_device.ol_waitevent, 5 * HZ);
 		post_status(&dm_device);
 	}
 }
@@ -1706,6 +1700,7 @@ static int balloon_probe(struct hv_device *dev,
 
 #ifdef CONFIG_MEMORY_HOTPLUG
 	set_online_page_callback(&hv_online_page);
+	init_completion(&dm_device.ol_waitevent);
 	register_memory_notifier(&hv_memory_nb);
 #endif
 
-- 
2.24.1


^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [PATCH v3 6/8] mm/memory_hotplug: unexport memhp_auto_online
  2020-03-19 13:12 [PATCH v3 0/8] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
                   ` (4 preceding siblings ...)
  2020-03-19 13:12 ` [PATCH v3 5/8] hv_balloon: don't check for memhp_auto_online manually David Hildenbrand
@ 2020-03-19 13:12 ` David Hildenbrand
  2020-03-19 16:52   ` Pankaj Gupta
  2020-03-19 13:12 ` [PATCH v3 7/8] mm/memory_hotplug: convert memhp_auto_online to store an online_type David Hildenbrand
                   ` (2 subsequent siblings)
  8 siblings, 1 reply; 19+ messages in thread
From: David Hildenbrand @ 2020-03-19 13:12 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-mm, linuxppc-dev, linux-hyperv, David Hildenbrand,
	Wei Yang, Michal Hocko, Andrew Morton, Michal Hocko,
	Oscar Salvador, Rafael J. Wysocki, Baoquan He

All in-tree users except the mm-core are gone. Let's drop the export.

Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 mm/memory_hotplug.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index da6aab272c9b..e21a7d53ade5 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -71,7 +71,6 @@ bool memhp_auto_online;
 #else
 bool memhp_auto_online = true;
 #endif
-EXPORT_SYMBOL_GPL(memhp_auto_online);
 
 static int __init setup_memhp_default_state(char *str)
 {
-- 
2.24.1


^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [PATCH v3 7/8] mm/memory_hotplug: convert memhp_auto_online to store an online_type
  2020-03-19 13:12 [PATCH v3 0/8] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
                   ` (5 preceding siblings ...)
  2020-03-19 13:12 ` [PATCH v3 6/8] mm/memory_hotplug: unexport memhp_auto_online David Hildenbrand
@ 2020-03-19 13:12 ` David Hildenbrand
  2020-03-19 17:19   ` Pankaj Gupta
  2020-03-19 13:12 ` [PATCH v3 8/8] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
  2020-03-20 10:01 ` [PATCH v3 0/8] " Baoquan He
  8 siblings, 1 reply; 19+ messages in thread
From: David Hildenbrand @ 2020-03-19 13:12 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-mm, linuxppc-dev, linux-hyperv, David Hildenbrand,
	Wei Yang, Michal Hocko, Greg Kroah-Hartman, Andrew Morton,
	Michal Hocko, Oscar Salvador, Rafael J. Wysocki, Baoquan He

... and rename it to memhp_default_online_type. This is a preparation
for more detailed default online behavior.

Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 drivers/base/memory.c          | 10 ++++------
 include/linux/memory_hotplug.h |  3 ++-
 mm/memory_hotplug.c            | 11 ++++++-----
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 8a7f29c0bf97..8d3e16dab69f 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -386,10 +386,8 @@ static DEVICE_ATTR_RO(block_size_bytes);
 static ssize_t auto_online_blocks_show(struct device *dev,
 				       struct device_attribute *attr, char *buf)
 {
-	if (memhp_auto_online)
-		return sprintf(buf, "online\n");
-	else
-		return sprintf(buf, "offline\n");
+	return sprintf(buf, "%s\n",
+		       online_type_to_str[memhp_default_online_type]);
 }
 
 static ssize_t auto_online_blocks_store(struct device *dev,
@@ -397,9 +395,9 @@ static ssize_t auto_online_blocks_store(struct device *dev,
 					const char *buf, size_t count)
 {
 	if (sysfs_streq(buf, "online"))
-		memhp_auto_online = true;
+		memhp_default_online_type = MMOP_ONLINE;
 	else if (sysfs_streq(buf, "offline"))
-		memhp_auto_online = false;
+		memhp_default_online_type = MMOP_OFFLINE;
 	else
 		return -EINVAL;
 
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 76f3c617a8ab..6d6f85bb66e9 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -118,7 +118,8 @@ extern int arch_add_memory(int nid, u64 start, u64 size,
 			   struct mhp_params *params);
 extern u64 max_mem_size;
 
-extern bool memhp_auto_online;
+/* Default online_type (MMOP_*) when new memory blocks are added. */
+extern int memhp_default_online_type;
 /* If movable_node boot option specified */
 extern bool movable_node_enabled;
 static inline bool movable_node_is_enabled(void)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e21a7d53ade5..4efcf8cb9ac5 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -67,17 +67,17 @@ void put_online_mems(void)
 bool movable_node_enabled = false;
 
 #ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
-bool memhp_auto_online;
+int memhp_default_online_type = MMOP_OFFLINE;
 #else
-bool memhp_auto_online = true;
+int memhp_default_online_type = MMOP_ONLINE;
 #endif
 
 static int __init setup_memhp_default_state(char *str)
 {
 	if (!strcmp(str, "online"))
-		memhp_auto_online = true;
+		memhp_default_online_type = MMOP_ONLINE;
 	else if (!strcmp(str, "offline"))
-		memhp_auto_online = false;
+		memhp_default_online_type = MMOP_OFFLINE;
 
 	return 1;
 }
@@ -993,6 +993,7 @@ static int check_hotplug_memory_range(u64 start, u64 size)
 
 static int online_memory_block(struct memory_block *mem, void *arg)
 {
+	mem->online_type = memhp_default_online_type;
 	return device_online(&mem->dev);
 }
 
@@ -1065,7 +1066,7 @@ int __ref add_memory_resource(int nid, struct resource *res)
 	mem_hotplug_done();
 
 	/* online pages if requested */
-	if (memhp_auto_online)
+	if (memhp_default_online_type != MMOP_OFFLINE)
 		walk_memory_blocks(start, size, NULL, online_memory_block);
 
 	return ret;
-- 
2.24.1


^ permalink raw reply related	[flat|nested] 19+ messages in thread

* [PATCH v3 8/8] mm/memory_hotplug: allow to specify a default online_type
  2020-03-19 13:12 [PATCH v3 0/8] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
                   ` (6 preceding siblings ...)
  2020-03-19 13:12 ` [PATCH v3 7/8] mm/memory_hotplug: convert memhp_auto_online to store an online_type David Hildenbrand
@ 2020-03-19 13:12 ` David Hildenbrand
  2020-03-19 17:26   ` Pankaj Gupta
  2020-03-20 10:01 ` [PATCH v3 0/8] " Baoquan He
  8 siblings, 1 reply; 19+ messages in thread
From: David Hildenbrand @ 2020-03-19 13:12 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-mm, linuxppc-dev, linux-hyperv, David Hildenbrand,
	Wei Yang, Michal Hocko, Greg Kroah-Hartman, Andrew Morton,
	Michal Hocko, Oscar Salvador, Rafael J. Wysocki, Baoquan He

For now, distributions implement advanced udev rules to essentially
- Don't online any hotplugged memory (s390x)
- Online all memory to ZONE_NORMAL (e.g., most virt environments like
  hyperv)
- Online all memory to ZONE_MOVABLE in case the zone imbalance is taken
  care of (e.g., bare metal, special virt environments)

In summary: All memory is usually onlined the same way, however, the
kernel always has to ask user space to come up with the same answer.
E.g., Hyper-V always waits for a memory block to get onlined before
continuing, otherwise it might end up adding memory faster than
onlining it, which can result in strange OOM situations. This waiting
slows down adding of a bigger amount of memory.

Let's allow to specify a default online_type, not just "online" and
"offline". This allows distributions to configure the default online_type
when booting up and be done with it.

We can now specify "offline", "online", "online_movable" and
"online_kernel" via
- "memhp_default_state=" on the kernel cmdline
- /sys/devices/system/memory/auto_online_blocks
just like we are able to specify for a single memory block via
/sys/devices/system/memory/memoryX/state

Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 drivers/base/memory.c          | 11 +++++------
 include/linux/memory_hotplug.h |  2 ++
 mm/memory_hotplug.c            |  8 ++++----
 3 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 8d3e16dab69f..2b09b68b9f78 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -35,7 +35,7 @@ static const char *const online_type_to_str[] = {
 	[MMOP_ONLINE_MOVABLE] = "online_movable",
 };
 
-static int memhp_online_type_from_str(const char *str)
+int memhp_online_type_from_str(const char *str)
 {
 	int i;
 
@@ -394,13 +394,12 @@ static ssize_t auto_online_blocks_store(struct device *dev,
 					struct device_attribute *attr,
 					const char *buf, size_t count)
 {
-	if (sysfs_streq(buf, "online"))
-		memhp_default_online_type = MMOP_ONLINE;
-	else if (sysfs_streq(buf, "offline"))
-		memhp_default_online_type = MMOP_OFFLINE;
-	else
+	const int online_type = memhp_online_type_from_str(buf);
+
+	if (online_type < 0)
 		return -EINVAL;
 
+	memhp_default_online_type = online_type;
 	return count;
 }
 
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 6d6f85bb66e9..93d9ada74ddd 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -118,6 +118,8 @@ extern int arch_add_memory(int nid, u64 start, u64 size,
 			   struct mhp_params *params);
 extern u64 max_mem_size;
 
+extern int memhp_online_type_from_str(const char *str);
+
 /* Default online_type (MMOP_*) when new memory blocks are added. */
 extern int memhp_default_online_type;
 /* If movable_node boot option specified */
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 4efcf8cb9ac5..89197163d138 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -74,10 +74,10 @@ int memhp_default_online_type = MMOP_ONLINE;
 
 static int __init setup_memhp_default_state(char *str)
 {
-	if (!strcmp(str, "online"))
-		memhp_default_online_type = MMOP_ONLINE;
-	else if (!strcmp(str, "offline"))
-		memhp_default_online_type = MMOP_OFFLINE;
+	const int online_type = memhp_online_type_from_str(str);
+
+	if (online_type >= 0)
+		memhp_default_online_type = online_type;
 
 	return 1;
 }
-- 
2.24.1


^ permalink raw reply related	[flat|nested] 19+ messages in thread

* Re: [PATCH v3 1/8] drivers/base/memory: rename MMOP_ONLINE_KEEP to MMOP_ONLINE
  2020-03-19 13:12 ` [PATCH v3 1/8] drivers/base/memory: rename MMOP_ONLINE_KEEP to MMOP_ONLINE David Hildenbrand
@ 2020-03-19 16:28   ` Pankaj Gupta
  0 siblings, 0 replies; 19+ messages in thread
From: Pankaj Gupta @ 2020-03-19 16:28 UTC (permalink / raw)
  To: David Hildenbrand
  Cc: linux-kernel, linux-mm, linuxppc-dev, linux-hyperv, Wei Yang,
	Greg Kroah-Hartman, Andrew Morton, Michal Hocko, Oscar Salvador,
	Rafael J. Wysocki, Baoquan He

> The name is misleading and it's not really clear what is "kept". Let's just
> name it like the online_type name we expose to user space ("online").
>
> Add some documentation to the types.
>
> Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Baoquan He <bhe@redhat.com>
> Cc: Wei Yang <richard.weiyang@gmail.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  drivers/base/memory.c          | 9 +++++----
>  include/linux/memory_hotplug.h | 6 +++++-
>  2 files changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index 6448c9ece2cb..8c5ce42c0fc3 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -216,7 +216,7 @@ static int memory_subsys_online(struct device *dev)
>          * attribute and need to set the online_type.
>          */
>         if (mem->online_type < 0)
> -               mem->online_type = MMOP_ONLINE_KEEP;
> +               mem->online_type = MMOP_ONLINE;
>
>         ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
>
> @@ -251,7 +251,7 @@ static ssize_t state_store(struct device *dev, struct device_attribute *attr,
>         else if (sysfs_streq(buf, "online_movable"))
>                 online_type = MMOP_ONLINE_MOVABLE;
>         else if (sysfs_streq(buf, "online"))
> -               online_type = MMOP_ONLINE_KEEP;
> +               online_type = MMOP_ONLINE;
>         else if (sysfs_streq(buf, "offline"))
>                 online_type = MMOP_OFFLINE;
>         else {
> @@ -262,7 +262,7 @@ static ssize_t state_store(struct device *dev, struct device_attribute *attr,
>         switch (online_type) {
>         case MMOP_ONLINE_KERNEL:
>         case MMOP_ONLINE_MOVABLE:
> -       case MMOP_ONLINE_KEEP:
> +       case MMOP_ONLINE:
>                 /* mem->online_type is protected by device_hotplug_lock */
>                 mem->online_type = online_type;
>                 ret = device_online(&mem->dev);
> @@ -342,7 +342,8 @@ static ssize_t valid_zones_show(struct device *dev,
>         }
>
>         nid = mem->nid;
> -       default_zone = zone_for_pfn_range(MMOP_ONLINE_KEEP, nid, start_pfn, nr_pages);
> +       default_zone = zone_for_pfn_range(MMOP_ONLINE, nid, start_pfn,
> +                                         nr_pages);
>         strcat(buf, default_zone->name);
>
>         print_allowed_zone(buf, nid, start_pfn, nr_pages, MMOP_ONLINE_KERNEL,
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index 3195d11876ea..3aaf00db224c 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -47,9 +47,13 @@ enum {
>
>  /* Types for control the zone type of onlined and offlined memory */
>  enum {
> +       /* Offline the memory. */
>         MMOP_OFFLINE = -1,
> -       MMOP_ONLINE_KEEP,
> +       /* Online the memory. Zone depends, see default_zone_for_pfn(). */
> +       MMOP_ONLINE,
> +       /* Online the memory to ZONE_NORMAL. */
>         MMOP_ONLINE_KERNEL,
> +       /* Online the memory to ZONE_MOVABLE. */
>         MMOP_ONLINE_MOVABLE,
>  };
>
> --
Looks good to me.

Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>

> 2.24.1
>
>

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH v3 2/8] drivers/base/memory: map MMOP_OFFLINE to 0
  2020-03-19 13:12 ` [PATCH v3 2/8] drivers/base/memory: map MMOP_OFFLINE to 0 David Hildenbrand
@ 2020-03-19 16:29   ` Pankaj Gupta
  0 siblings, 0 replies; 19+ messages in thread
From: Pankaj Gupta @ 2020-03-19 16:29 UTC (permalink / raw)
  To: David Hildenbrand
  Cc: linux-kernel, linux-mm, linuxppc-dev, linux-hyperv, Wei Yang,
	Michal Hocko, Greg Kroah-Hartman, Andrew Morton, Michal Hocko,
	Oscar Salvador, Rafael J. Wysocki, Baoquan He

> Historically, we used the value -1. Just treat 0 as the special
> case now. Clarify a comment (which was wrong, when we come via
> device_online() the first time, the online_type would have been 0 /
> MEM_ONLINE). The default is now always MMOP_OFFLINE. This removes the
> last user of the manual "-1", which didn't use the enum value.
>
> This is a preparation to use the online_type as an array index.
>
> Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
> Acked-by: Michal Hocko <mhocko@suse.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Baoquan He <bhe@redhat.com>
> Cc: Wei Yang <richard.weiyang@gmail.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  drivers/base/memory.c          | 11 ++++-------
>  include/linux/memory_hotplug.h |  2 +-
>  2 files changed, 5 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index 8c5ce42c0fc3..e7e77cafef80 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -211,17 +211,14 @@ static int memory_subsys_online(struct device *dev)
>                 return 0;
>
>         /*
> -        * If we are called from state_store(), online_type will be
> -        * set >= 0 Otherwise we were called from the device online
> -        * attribute and need to set the online_type.
> +        * When called via device_online() without configuring the online_type,
> +        * we want to default to MMOP_ONLINE.
>          */
> -       if (mem->online_type < 0)
> +       if (mem->online_type == MMOP_OFFLINE)
>                 mem->online_type = MMOP_ONLINE;
>
>         ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
> -
> -       /* clear online_type */
> -       mem->online_type = -1;
> +       mem->online_type = MMOP_OFFLINE;
>
>         return ret;
>  }
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index 3aaf00db224c..76f3c617a8ab 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -48,7 +48,7 @@ enum {
>  /* Types for control the zone type of onlined and offlined memory */
>  enum {
>         /* Offline the memory. */
> -       MMOP_OFFLINE = -1,
> +       MMOP_OFFLINE = 0,
>         /* Online the memory. Zone depends, see default_zone_for_pfn(). */
>         MMOP_ONLINE,
>         /* Online the memory to ZONE_NORMAL. */
> --
> 2.24.1

Looks good to me.
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
>
>

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH v3 3/8] drivers/base/memory: store mapping between MMOP_* and string in an array
  2020-03-19 13:12 ` [PATCH v3 3/8] drivers/base/memory: store mapping between MMOP_* and string in an array David Hildenbrand
@ 2020-03-19 16:33   ` Pankaj Gupta
  2020-03-20  7:36   ` Baoquan He
  1 sibling, 0 replies; 19+ messages in thread
From: Pankaj Gupta @ 2020-03-19 16:33 UTC (permalink / raw)
  To: David Hildenbrand
  Cc: linux-kernel, linux-mm, linuxppc-dev, linux-hyperv, Wei Yang,
	Michal Hocko, Greg Kroah-Hartman, Andrew Morton, Michal Hocko,
	Oscar Salvador, Rafael J. Wysocki, Baoquan He

> Let's use a simple array which we can reuse soon. While at it, move the
> string->mmop conversion out of the device hotplug lock.
>
> Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
> Acked-by: Michal Hocko <mhocko@suse.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Baoquan He <bhe@redhat.com>
> Cc: Wei Yang <richard.weiyang@gmail.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  drivers/base/memory.c | 38 +++++++++++++++++++++++---------------
>  1 file changed, 23 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index e7e77cafef80..8a7f29c0bf97 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -28,6 +28,24 @@
>
>  #define MEMORY_CLASS_NAME      "memory"
>
> +static const char *const online_type_to_str[] = {
> +       [MMOP_OFFLINE] = "offline",
> +       [MMOP_ONLINE] = "online",
> +       [MMOP_ONLINE_KERNEL] = "online_kernel",
> +       [MMOP_ONLINE_MOVABLE] = "online_movable",
> +};
> +
> +static int memhp_online_type_from_str(const char *str)
> +{
> +       int i;
> +
> +       for (i = 0; i < ARRAY_SIZE(online_type_to_str); i++) {
> +               if (sysfs_streq(str, online_type_to_str[i]))
> +                       return i;
> +       }
> +       return -EINVAL;
> +}
> +
>  #define to_memory_block(dev) container_of(dev, struct memory_block, dev)
>
>  static int sections_per_block;
> @@ -236,26 +254,17 @@ static int memory_subsys_offline(struct device *dev)
>  static ssize_t state_store(struct device *dev, struct device_attribute *attr,
>                            const char *buf, size_t count)
>  {
> +       const int online_type = memhp_online_type_from_str(buf);
>         struct memory_block *mem = to_memory_block(dev);
> -       int ret, online_type;
> +       int ret;
> +
> +       if (online_type < 0)
> +               return -EINVAL;
>
>         ret = lock_device_hotplug_sysfs();
>         if (ret)
>                 return ret;
>
> -       if (sysfs_streq(buf, "online_kernel"))
> -               online_type = MMOP_ONLINE_KERNEL;
> -       else if (sysfs_streq(buf, "online_movable"))
> -               online_type = MMOP_ONLINE_MOVABLE;
> -       else if (sysfs_streq(buf, "online"))
> -               online_type = MMOP_ONLINE;
> -       else if (sysfs_streq(buf, "offline"))
> -               online_type = MMOP_OFFLINE;
> -       else {
> -               ret = -EINVAL;
> -               goto err;
> -       }
> -
>         switch (online_type) {
>         case MMOP_ONLINE_KERNEL:
>         case MMOP_ONLINE_MOVABLE:
> @@ -271,7 +280,6 @@ static ssize_t state_store(struct device *dev, struct device_attribute *attr,
>                 ret = -EINVAL; /* should never happen */
>         }
>
> -err:
>         unlock_device_hotplug();
>
>         if (ret < 0)
> --

Nice cleanup patch.
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>

> 2.24.1
>
>

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH v3 6/8] mm/memory_hotplug: unexport memhp_auto_online
  2020-03-19 13:12 ` [PATCH v3 6/8] mm/memory_hotplug: unexport memhp_auto_online David Hildenbrand
@ 2020-03-19 16:52   ` Pankaj Gupta
  0 siblings, 0 replies; 19+ messages in thread
From: Pankaj Gupta @ 2020-03-19 16:52 UTC (permalink / raw)
  To: David Hildenbrand
  Cc: linux-kernel, linux-mm, linuxppc-dev, linux-hyperv, Wei Yang,
	Michal Hocko, Andrew Morton, Michal Hocko, Oscar Salvador,
	Rafael J. Wysocki, Baoquan He

> All in-tree users except the mm-core are gone. Let's drop the export.
>
> Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
> Acked-by: Michal Hocko <mhocko@suse.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Baoquan He <bhe@redhat.com>
> Cc: Wei Yang <richard.weiyang@gmail.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  mm/memory_hotplug.c | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index da6aab272c9b..e21a7d53ade5 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -71,7 +71,6 @@ bool memhp_auto_online;
>  #else
>  bool memhp_auto_online = true;
>  #endif
> -EXPORT_SYMBOL_GPL(memhp_auto_online);
>
>  static int __init setup_memhp_default_state(char *str)
>  {
> --
> 2.24.1

Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
>
>

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH v3 7/8] mm/memory_hotplug: convert memhp_auto_online to store an online_type
  2020-03-19 13:12 ` [PATCH v3 7/8] mm/memory_hotplug: convert memhp_auto_online to store an online_type David Hildenbrand
@ 2020-03-19 17:19   ` Pankaj Gupta
  0 siblings, 0 replies; 19+ messages in thread
From: Pankaj Gupta @ 2020-03-19 17:19 UTC (permalink / raw)
  To: David Hildenbrand
  Cc: linux-kernel, linux-mm, linuxppc-dev, linux-hyperv, Wei Yang,
	Michal Hocko, Greg Kroah-Hartman, Andrew Morton, Michal Hocko,
	Oscar Salvador, Rafael J. Wysocki, Baoquan He

> ... and rename it to memhp_default_online_type. This is a preparation
> for more detailed default online behavior.
>
> Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
> Acked-by: Michal Hocko <mhocko@suse.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Baoquan He <bhe@redhat.com>
> Cc: Wei Yang <richard.weiyang@gmail.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  drivers/base/memory.c          | 10 ++++------
>  include/linux/memory_hotplug.h |  3 ++-
>  mm/memory_hotplug.c            | 11 ++++++-----
>  3 files changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index 8a7f29c0bf97..8d3e16dab69f 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -386,10 +386,8 @@ static DEVICE_ATTR_RO(block_size_bytes);
>  static ssize_t auto_online_blocks_show(struct device *dev,
>                                        struct device_attribute *attr, char *buf)
>  {
> -       if (memhp_auto_online)
> -               return sprintf(buf, "online\n");
> -       else
> -               return sprintf(buf, "offline\n");
> +       return sprintf(buf, "%s\n",
> +                      online_type_to_str[memhp_default_online_type]);
>  }
>
>  static ssize_t auto_online_blocks_store(struct device *dev,
> @@ -397,9 +395,9 @@ static ssize_t auto_online_blocks_store(struct device *dev,
>                                         const char *buf, size_t count)
>  {
>         if (sysfs_streq(buf, "online"))
> -               memhp_auto_online = true;
> +               memhp_default_online_type = MMOP_ONLINE;
>         else if (sysfs_streq(buf, "offline"))
> -               memhp_auto_online = false;
> +               memhp_default_online_type = MMOP_OFFLINE;
>         else
>                 return -EINVAL;
>
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index 76f3c617a8ab..6d6f85bb66e9 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -118,7 +118,8 @@ extern int arch_add_memory(int nid, u64 start, u64 size,
>                            struct mhp_params *params);
>  extern u64 max_mem_size;
>
> -extern bool memhp_auto_online;
> +/* Default online_type (MMOP_*) when new memory blocks are added. */
> +extern int memhp_default_online_type;
>  /* If movable_node boot option specified */
>  extern bool movable_node_enabled;
>  static inline bool movable_node_is_enabled(void)
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index e21a7d53ade5..4efcf8cb9ac5 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -67,17 +67,17 @@ void put_online_mems(void)
>  bool movable_node_enabled = false;
>
>  #ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
> -bool memhp_auto_online;
> +int memhp_default_online_type = MMOP_OFFLINE;
>  #else
> -bool memhp_auto_online = true;
> +int memhp_default_online_type = MMOP_ONLINE;
>  #endif
>
>  static int __init setup_memhp_default_state(char *str)
>  {
>         if (!strcmp(str, "online"))
> -               memhp_auto_online = true;
> +               memhp_default_online_type = MMOP_ONLINE;
>         else if (!strcmp(str, "offline"))
> -               memhp_auto_online = false;
> +               memhp_default_online_type = MMOP_OFFLINE;
>
>         return 1;
>  }
> @@ -993,6 +993,7 @@ static int check_hotplug_memory_range(u64 start, u64 size)
>
>  static int online_memory_block(struct memory_block *mem, void *arg)
>  {
> +       mem->online_type = memhp_default_online_type;
>         return device_online(&mem->dev);
>  }
>
> @@ -1065,7 +1066,7 @@ int __ref add_memory_resource(int nid, struct resource *res)
>         mem_hotplug_done();
>
>         /* online pages if requested */
> -       if (memhp_auto_online)
> +       if (memhp_default_online_type != MMOP_OFFLINE)
>                 walk_memory_blocks(start, size, NULL, online_memory_block);
>
>         return ret;
> --

Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>

> 2.24.1
>
>

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH v3 8/8] mm/memory_hotplug: allow to specify a default online_type
  2020-03-19 13:12 ` [PATCH v3 8/8] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
@ 2020-03-19 17:26   ` Pankaj Gupta
  0 siblings, 0 replies; 19+ messages in thread
From: Pankaj Gupta @ 2020-03-19 17:26 UTC (permalink / raw)
  To: David Hildenbrand
  Cc: linux-kernel, linux-mm, linuxppc-dev, linux-hyperv, Wei Yang,
	Michal Hocko, Greg Kroah-Hartman, Andrew Morton, Michal Hocko,
	Oscar Salvador, Rafael J. Wysocki, Baoquan He

> For now, distributions implement advanced udev rules to essentially
> - Don't online any hotplugged memory (s390x)
> - Online all memory to ZONE_NORMAL (e.g., most virt environments like
>   hyperv)
> - Online all memory to ZONE_MOVABLE in case the zone imbalance is taken
>   care of (e.g., bare metal, special virt environments)
>
> In summary: All memory is usually onlined the same way, however, the
> kernel always has to ask user space to come up with the same answer.
> E.g., Hyper-V always waits for a memory block to get onlined before
> continuing, otherwise it might end up adding memory faster than
> onlining it, which can result in strange OOM situations. This waiting
> slows down adding of a bigger amount of memory.
>
> Let's allow to specify a default online_type, not just "online" and
> "offline". This allows distributions to configure the default online_type
> when booting up and be done with it.
>
> We can now specify "offline", "online", "online_movable" and
> "online_kernel" via
> - "memhp_default_state=" on the kernel cmdline
> - /sys/devices/system/memory/auto_online_blocks
> just like we are able to specify for a single memory block via
> /sys/devices/system/memory/memoryX/state
>
> Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
> Acked-by: Michal Hocko <mhocko@suse.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Baoquan He <bhe@redhat.com>
> Cc: Wei Yang <richard.weiyang@gmail.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  drivers/base/memory.c          | 11 +++++------
>  include/linux/memory_hotplug.h |  2 ++
>  mm/memory_hotplug.c            |  8 ++++----
>  3 files changed, 11 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index 8d3e16dab69f..2b09b68b9f78 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -35,7 +35,7 @@ static const char *const online_type_to_str[] = {
>         [MMOP_ONLINE_MOVABLE] = "online_movable",
>  };
>
> -static int memhp_online_type_from_str(const char *str)
> +int memhp_online_type_from_str(const char *str)
>  {
>         int i;
>
> @@ -394,13 +394,12 @@ static ssize_t auto_online_blocks_store(struct device *dev,
>                                         struct device_attribute *attr,
>                                         const char *buf, size_t count)
>  {
> -       if (sysfs_streq(buf, "online"))
> -               memhp_default_online_type = MMOP_ONLINE;
> -       else if (sysfs_streq(buf, "offline"))
> -               memhp_default_online_type = MMOP_OFFLINE;
> -       else
> +       const int online_type = memhp_online_type_from_str(buf);
> +
> +       if (online_type < 0)
>                 return -EINVAL;
>
> +       memhp_default_online_type = online_type;
>         return count;
>  }
>
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index 6d6f85bb66e9..93d9ada74ddd 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -118,6 +118,8 @@ extern int arch_add_memory(int nid, u64 start, u64 size,
>                            struct mhp_params *params);
>  extern u64 max_mem_size;
>
> +extern int memhp_online_type_from_str(const char *str);
> +
>  /* Default online_type (MMOP_*) when new memory blocks are added. */
>  extern int memhp_default_online_type;
>  /* If movable_node boot option specified */
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 4efcf8cb9ac5..89197163d138 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -74,10 +74,10 @@ int memhp_default_online_type = MMOP_ONLINE;
>
>  static int __init setup_memhp_default_state(char *str)
>  {
> -       if (!strcmp(str, "online"))
> -               memhp_default_online_type = MMOP_ONLINE;
> -       else if (!strcmp(str, "offline"))
> -               memhp_default_online_type = MMOP_OFFLINE;
> +       const int online_type = memhp_online_type_from_str(str);
> +
> +       if (online_type >= 0)
> +               memhp_default_online_type = online_type;
>
>         return 1;
>  }
> --
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>

> 2.24.1
>
>

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH v3 3/8] drivers/base/memory: store mapping between MMOP_* and string in an array
  2020-03-19 13:12 ` [PATCH v3 3/8] drivers/base/memory: store mapping between MMOP_* and string in an array David Hildenbrand
  2020-03-19 16:33   ` Pankaj Gupta
@ 2020-03-20  7:36   ` Baoquan He
  2020-03-20  9:50     ` David Hildenbrand
  1 sibling, 1 reply; 19+ messages in thread
From: Baoquan He @ 2020-03-20  7:36 UTC (permalink / raw)
  To: David Hildenbrand
  Cc: linux-kernel, linux-mm, linuxppc-dev, linux-hyperv, Wei Yang,
	Michal Hocko, Greg Kroah-Hartman, Andrew Morton, Michal Hocko,
	Oscar Salvador, Rafael J. Wysocki

On 03/19/20 at 02:12pm, David Hildenbrand wrote:
> Let's use a simple array which we can reuse soon. While at it, move the
> string->mmop conversion out of the device hotplug lock.
> 
> Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
> Acked-by: Michal Hocko <mhocko@suse.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Baoquan He <bhe@redhat.com>
> Cc: Wei Yang <richard.weiyang@gmail.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  drivers/base/memory.c | 38 +++++++++++++++++++++++---------------
>  1 file changed, 23 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index e7e77cafef80..8a7f29c0bf97 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -28,6 +28,24 @@
>  
>  #define MEMORY_CLASS_NAME	"memory"
>  
> +static const char *const online_type_to_str[] = {
> +	[MMOP_OFFLINE] = "offline",
> +	[MMOP_ONLINE] = "online",
> +	[MMOP_ONLINE_KERNEL] = "online_kernel",
> +	[MMOP_ONLINE_MOVABLE] = "online_movable",
> +};
> +
> +static int memhp_online_type_from_str(const char *str)
> +{
> +	int i;

I would change it as: 

	for (int i = 0; i < ARRAY_SIZE(online_type_to_str); i++) {

> +
> +	for (i = 0; i < ARRAY_SIZE(online_type_to_str); i++) {
> +		if (sysfs_streq(str, online_type_to_str[i]))
> +			return i;
> +	}
> +	return -EINVAL;
> +}
> +
>  #define to_memory_block(dev) container_of(dev, struct memory_block, dev)
>  
>  static int sections_per_block;
> @@ -236,26 +254,17 @@ static int memory_subsys_offline(struct device *dev)
>  static ssize_t state_store(struct device *dev, struct device_attribute *attr,
>  			   const char *buf, size_t count)
>  {
> +	const int online_type = memhp_online_type_from_str(buf);
>  	struct memory_block *mem = to_memory_block(dev);
> -	int ret, online_type;
> +	int ret;
> +
> +	if (online_type < 0)
> +		return -EINVAL;
>  
>  	ret = lock_device_hotplug_sysfs();
>  	if (ret)
>  		return ret;
>  
> -	if (sysfs_streq(buf, "online_kernel"))
> -		online_type = MMOP_ONLINE_KERNEL;
> -	else if (sysfs_streq(buf, "online_movable"))
> -		online_type = MMOP_ONLINE_MOVABLE;
> -	else if (sysfs_streq(buf, "online"))
> -		online_type = MMOP_ONLINE;
> -	else if (sysfs_streq(buf, "offline"))
> -		online_type = MMOP_OFFLINE;
> -	else {
> -		ret = -EINVAL;
> -		goto err;
> -	}
> -
>  	switch (online_type) {
>  	case MMOP_ONLINE_KERNEL:
>  	case MMOP_ONLINE_MOVABLE:
> @@ -271,7 +280,6 @@ static ssize_t state_store(struct device *dev, struct device_attribute *attr,
>  		ret = -EINVAL; /* should never happen */
>  	}
>  
> -err:
>  	unlock_device_hotplug();
>  
>  	if (ret < 0)
> -- 
> 2.24.1
> 


^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH v3 3/8] drivers/base/memory: store mapping between MMOP_* and string in an array
  2020-03-20  7:36   ` Baoquan He
@ 2020-03-20  9:50     ` David Hildenbrand
  2020-03-20  9:59       ` Baoquan He
  0 siblings, 1 reply; 19+ messages in thread
From: David Hildenbrand @ 2020-03-20  9:50 UTC (permalink / raw)
  To: Baoquan He
  Cc: linux-kernel, linux-mm, linuxppc-dev, linux-hyperv, Wei Yang,
	Michal Hocko, Greg Kroah-Hartman, Andrew Morton, Michal Hocko,
	Oscar Salvador, Rafael J. Wysocki

On 20.03.20 08:36, Baoquan He wrote:
> On 03/19/20 at 02:12pm, David Hildenbrand wrote:
>> Let's use a simple array which we can reuse soon. While at it, move the
>> string->mmop conversion out of the device hotplug lock.
>>
>> Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
>> Acked-by: Michal Hocko <mhocko@suse.com>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: Michal Hocko <mhocko@kernel.org>
>> Cc: Oscar Salvador <osalvador@suse.de>
>> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
>> Cc: Baoquan He <bhe@redhat.com>
>> Cc: Wei Yang <richard.weiyang@gmail.com>
>> Signed-off-by: David Hildenbrand <david@redhat.com>
>> ---
>>  drivers/base/memory.c | 38 +++++++++++++++++++++++---------------
>>  1 file changed, 23 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
>> index e7e77cafef80..8a7f29c0bf97 100644
>> --- a/drivers/base/memory.c
>> +++ b/drivers/base/memory.c
>> @@ -28,6 +28,24 @@
>>  
>>  #define MEMORY_CLASS_NAME	"memory"
>>  
>> +static const char *const online_type_to_str[] = {
>> +	[MMOP_OFFLINE] = "offline",
>> +	[MMOP_ONLINE] = "online",
>> +	[MMOP_ONLINE_KERNEL] = "online_kernel",
>> +	[MMOP_ONLINE_MOVABLE] = "online_movable",
>> +};
>> +
>> +static int memhp_online_type_from_str(const char *str)
>> +{
>> +	int i;
> 
> I would change it as: 
> 
> 	for (int i = 0; i < ARRAY_SIZE(online_type_to_str); i++) {
> 

That's not allowed by the C90 standard (and -std=gnu89).

$ gcc main.c -std=gnu89
main.c: In function 'main':
main.c:3:2: error: 'for' loop initial declarations are only allowed in
C99 or C11 mode
    3 |  for (int i = 0; i < 8; i++) {
      |  ^~~

One of the reasons why
	git grep "for (int "

will result in very little hits (IOW, only 5 in driver code only).

-- 
Thanks,

David / dhildenb


^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH v3 3/8] drivers/base/memory: store mapping between MMOP_* and string in an array
  2020-03-20  9:50     ` David Hildenbrand
@ 2020-03-20  9:59       ` Baoquan He
  0 siblings, 0 replies; 19+ messages in thread
From: Baoquan He @ 2020-03-20  9:59 UTC (permalink / raw)
  To: David Hildenbrand
  Cc: linux-kernel, linux-mm, linuxppc-dev, linux-hyperv, Wei Yang,
	Michal Hocko, Greg Kroah-Hartman, Andrew Morton, Michal Hocko,
	Oscar Salvador, Rafael J. Wysocki

On 03/20/20 at 10:50am, David Hildenbrand wrote:
> On 20.03.20 08:36, Baoquan He wrote:
> > On 03/19/20 at 02:12pm, David Hildenbrand wrote:
> >> Let's use a simple array which we can reuse soon. While at it, move the
> >> string->mmop conversion out of the device hotplug lock.
> >>
> >> Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
> >> Acked-by: Michal Hocko <mhocko@suse.com>
> >> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> >> Cc: Andrew Morton <akpm@linux-foundation.org>
> >> Cc: Michal Hocko <mhocko@kernel.org>
> >> Cc: Oscar Salvador <osalvador@suse.de>
> >> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> >> Cc: Baoquan He <bhe@redhat.com>
> >> Cc: Wei Yang <richard.weiyang@gmail.com>
> >> Signed-off-by: David Hildenbrand <david@redhat.com>
> >> ---
> >>  drivers/base/memory.c | 38 +++++++++++++++++++++++---------------
> >>  1 file changed, 23 insertions(+), 15 deletions(-)
> >>
> >> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> >> index e7e77cafef80..8a7f29c0bf97 100644
> >> --- a/drivers/base/memory.c
> >> +++ b/drivers/base/memory.c
> >> @@ -28,6 +28,24 @@
> >>  
> >>  #define MEMORY_CLASS_NAME	"memory"
> >>  
> >> +static const char *const online_type_to_str[] = {
> >> +	[MMOP_OFFLINE] = "offline",
> >> +	[MMOP_ONLINE] = "online",
> >> +	[MMOP_ONLINE_KERNEL] = "online_kernel",
> >> +	[MMOP_ONLINE_MOVABLE] = "online_movable",
> >> +};
> >> +
> >> +static int memhp_online_type_from_str(const char *str)
> >> +{
> >> +	int i;
> > 
> > I would change it as: 
> > 
> > 	for (int i = 0; i < ARRAY_SIZE(online_type_to_str); i++) {
> > 
> 
> That's not allowed by the C90 standard (and -std=gnu89).
> 
> $ gcc main.c -std=gnu89
> main.c: In function 'main':
> main.c:3:2: error: 'for' loop initial declarations are only allowed in
> C99 or C11 mode
>     3 |  for (int i = 0; i < 8; i++) {
>       |  ^~~

Good to know, thanks.

> 
> One of the reasons why
> 	git grep "for (int "
> 
> will result in very little hits (IOW, only 5 in driver code only).
> 
> -- 
> Thanks,
> 
> David / dhildenb


^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [PATCH v3 0/8] mm/memory_hotplug: allow to specify a default online_type
  2020-03-19 13:12 [PATCH v3 0/8] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
                   ` (7 preceding siblings ...)
  2020-03-19 13:12 ` [PATCH v3 8/8] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
@ 2020-03-20 10:01 ` Baoquan He
  8 siblings, 0 replies; 19+ messages in thread
From: Baoquan He @ 2020-03-20 10:01 UTC (permalink / raw)
  To: David Hildenbrand
  Cc: linux-kernel, linux-mm, linuxppc-dev, linux-hyperv,
	Vitaly Kuznetsov, Yumei Huang, Igor Mammedov, Eduardo Habkost,
	Milan Zamazal, Andrew Morton, Benjamin Herrenschmidt,
	Greg Kroah-Hartman, Haiyang Zhang, K. Y. Srinivasan,
	Michael Ellerman, Michal Hocko, Michal Hocko, Oscar Salvador,
	Paul Mackerras, Rafael J. Wysocki, Stephen Hemminger, Wei Liu,
	Wei Yang

On 03/19/20 at 02:12pm, David Hildenbrand wrote:
> Distributions nowadays use udev rules ([1] [2]) to specify if and
> how to online hotplugged memory. The rules seem to get more complex with
> many special cases. Due to the various special cases,
> CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE cannot be used. All memory hotplug
> is handled via udev rules.
> 
> Everytime we hotplug memory, the udev rule will come to the same
> conclusion. Especially Hyper-V (but also soon virtio-mem) add a lot of
> memory in separate memory blocks and wait for memory to get onlined by user
> space before continuing to add more memory blocks (to not add memory faster
> than it is getting onlined). This of course slows down the whole memory
> hotplug process.
> 
> To make the job of distributions easier and to avoid udev rules that get
> more and more complicated, let's extend the mechanism provided by
> - /sys/devices/system/memory/auto_online_blocks
> - "memhp_default_state=" on the kernel cmdline
> to be able to specify also "online_movable" as well as "online_kernel"
> 
> v2 -> v3:
> - "hv_balloon: don't check for memhp_auto_online manually"
> -- init_completion() before register_memory_notifier()
> - Minor typo fix
> 
> v1 -> v2:
> - Tweaked some patch descriptions
> - Added
> -- "powernv/memtrace: always online added memory blocks"
> -- "hv_balloon: don't check for memhp_auto_online manually"
> -- "mm/memory_hotplug: unexport memhp_auto_online"
> - "mm/memory_hotplug: convert memhp_auto_online to store an online_type"
> -- No longer touches hv/memtrace code

Ack the series.

Reviewed-by: Baoquan He <bhe@redhat.com>


^ permalink raw reply	[flat|nested] 19+ messages in thread

end of thread, other threads:[~2020-03-20 10:01 UTC | newest]

Thread overview: 19+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-03-19 13:12 [PATCH v3 0/8] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
2020-03-19 13:12 ` [PATCH v3 1/8] drivers/base/memory: rename MMOP_ONLINE_KEEP to MMOP_ONLINE David Hildenbrand
2020-03-19 16:28   ` Pankaj Gupta
2020-03-19 13:12 ` [PATCH v3 2/8] drivers/base/memory: map MMOP_OFFLINE to 0 David Hildenbrand
2020-03-19 16:29   ` Pankaj Gupta
2020-03-19 13:12 ` [PATCH v3 3/8] drivers/base/memory: store mapping between MMOP_* and string in an array David Hildenbrand
2020-03-19 16:33   ` Pankaj Gupta
2020-03-20  7:36   ` Baoquan He
2020-03-20  9:50     ` David Hildenbrand
2020-03-20  9:59       ` Baoquan He
2020-03-19 13:12 ` [PATCH v3 4/8] powernv/memtrace: always online added memory blocks David Hildenbrand
2020-03-19 13:12 ` [PATCH v3 5/8] hv_balloon: don't check for memhp_auto_online manually David Hildenbrand
2020-03-19 13:12 ` [PATCH v3 6/8] mm/memory_hotplug: unexport memhp_auto_online David Hildenbrand
2020-03-19 16:52   ` Pankaj Gupta
2020-03-19 13:12 ` [PATCH v3 7/8] mm/memory_hotplug: convert memhp_auto_online to store an online_type David Hildenbrand
2020-03-19 17:19   ` Pankaj Gupta
2020-03-19 13:12 ` [PATCH v3 8/8] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
2020-03-19 17:26   ` Pankaj Gupta
2020-03-20 10:01 ` [PATCH v3 0/8] " Baoquan He

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).