From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
linux-hyperv@vger.kernel.org,
David Hildenbrand <david@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>,
Oscar Salvador <osalvador@suse.de>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Baoquan He <bhe@redhat.com>, Wei Yang <richard.weiyang@gmail.com>
Subject: [PATCH v1 5/5] mm/memory_hotplug: allow to specify a default online_type
Date: Wed, 11 Mar 2020 13:30:26 +0100 [thread overview]
Message-ID: <20200311123026.16071-6-david@redhat.com> (raw)
In-Reply-To: <20200311123026.16071-1-david@redhat.com>
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 userspace to come up with the same answer.
E.g., HyperV always waits for a memory block to get onlined before
continuing, otherwise it might end up adding memory faster than
hotplugging it, which can result in strange OOM situations.
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/systemn/memory/auto_online_blocks
just like we are able to specify for a single memory block via
/sys/devices/systemn/memory/memoryX/state
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 c6e090b34c4b..ef55115320fb 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -117,6 +117,8 @@ extern int arch_add_memory(int nid, u64 start, u64 size,
struct mhp_restrictions *restrictions);
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 01443c70aa27..4a96273eafa7 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -75,10 +75,10 @@ EXPORT_SYMBOL_GPL(memhp_default_online_type);
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
next prev parent reply other threads:[~2020-03-11 12:31 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-11 12:30 [PATCH v1 0/5] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
2020-03-11 12:30 ` [PATCH v1 1/5] drivers/base/memory: rename MMOP_ONLINE_KEEP to MMOP_ONLINE David Hildenbrand
2020-03-11 14:17 ` Wei Yang
2020-03-16 15:12 ` Michal Hocko
2020-03-16 15:17 ` David Hildenbrand
2020-03-11 12:30 ` [PATCH v1 2/5] drivers/base/memory: map MMOP_OFFLINE to 0 David Hildenbrand
2020-03-11 14:18 ` Wei Yang
2020-03-16 15:19 ` Michal Hocko
2020-03-11 12:30 ` [PATCH v1 3/5] drivers/base/memory: store mapping between MMOP_* and string in an array David Hildenbrand
2020-03-11 14:20 ` Wei Yang
2020-03-11 14:27 ` Wei Yang
2020-03-16 15:20 ` Michal Hocko
2020-03-11 12:30 ` [PATCH v1 4/5] mm/memory_hotplug: convert memhp_auto_online to store an online_type David Hildenbrand
2020-03-11 14:25 ` Wei Yang
2020-03-16 15:24 ` Michal Hocko
2020-03-16 15:34 ` David Hildenbrand
2020-03-16 15:46 ` Michal Hocko
2020-03-11 12:30 ` David Hildenbrand [this message]
2020-03-11 14:26 ` [PATCH v1 5/5] mm/memory_hotplug: allow to specify a default online_type Wei Yang
2020-03-11 15:20 ` David Hildenbrand
2020-03-11 16:55 ` Vitaly Kuznetsov
2020-03-11 17:05 ` David Hildenbrand
2020-03-16 15:31 ` Michal Hocko
2020-03-16 15:48 ` David Hildenbrand
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