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authorDavid Hildenbrand <david@redhat.com>2020-04-06 20:07:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-04-07 10:43:41 -0700
commit5f47adf762b78cae97de58d9ff01d2d44db09467 (patch)
treeee062258590575e716d7418e3a000611b4910efe /mm/memory_hotplug.c
parent862919e568356cc36288a11b42cd88ec3a7100e9 (diff)
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 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 Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Baoquan He <bhe@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Eduardo Habkost <ehabkost@redhat.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Igor Mammedov <imammedo@redhat.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Wei Liu <wei.liu@kernel.org> Cc: Yumei Huang <yuhuang@redhat.com> Link: http://lkml.kernel.org/r/20200317104942.11178-9-david@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory_hotplug.c')
-rw-r--r--mm/memory_hotplug.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 9436f7e6257a..2fb78c5ebaf3 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;
}