The patch titled
Subject: mm/memory_hotplug: allow to specify a default online_type
has been added to the -mm tree. Its filename is
mm-memory_hotplug-allow-to-specify-a-default-online_type.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memory_hotplug-allow-to-specify-a-default-online_type.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memory_hotplug-allow-to-specify-a-default-online_type.patch
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------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: mm/memory_hotplug: allow to specify a default online_type
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=3D" 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
Link: http://lkml.kernel.org/r/20200311123026.16071-6-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Wei Yang <richard.weiyang@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Cc: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Wei Liu <wei.liu@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/base/memory.c | 11 +++++------
include/linux/memory_hotplug.h | 2 ++
mm/memory_hotplug.c | 8 ++++----
3 files changed, 11 insertions(+), 10 deletions(-)
--- a/drivers/base/memory.c~mm-memory_hotplug-allow-to-specify-a-default-online_type
+++ a/drivers/base/memory.c
@@ -35,7 +35,7 @@ static const char *const online_type_to_
[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_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;
}
--- a/include/linux/memory_hotplug.h~mm-memory_hotplug-allow-to-specify-a-default-online_type
+++ a/include/linux/memory_hotplug.h
@@ -117,6 +117,8 @@ extern int arch_add_memory(int nid, u64
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 */
--- a/mm/memory_hotplug.c~mm-memory_hotplug-allow-to-specify-a-default-online_type
+++ a/mm/memory_hotplug.c
@@ -75,10 +75,10 @@ EXPORT_SYMBOL_GPL(memhp_default_online_t
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;
}
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
drivers-base-memoryc-cache-memory-blocks-in-xarray-to-accelerate-lookup-fix.patch
virtio-balloon-switch-back-to-oom-handler-for-virtio_balloon_f_deflate_on_oom.patch
drivers-base-memoryc-indicate-all-memory-blocks-as-removable.patch
drivers-base-memoryc-drop-section_count.patch
drivers-base-memoryc-drop-pages_correctly_probed.patch
mm-page_extc-drop-pfn_present-check-when-onlining.patch
mm-memory_hotplug-simplify-calculation-of-number-of-pages-in-__remove_pages.patch
mm-memory_hotplug-cleanup-__add_pages.patch
drivers-base-memory-rename-mmop_online_keep-to-mmop_online.patch
drivers-base-memory-map-mmop_offline-to-0.patch
drivers-base-memory-store-mapping-between-mmop_-and-string-in-an-array.patch
mm-memory_hotplug-convert-memhp_auto_online-to-store-an-online_type.patch
mm-memory_hotplug-allow-to-specify-a-default-online_type.patch
