On Tue, 22 Dec 2015, Andrew Morton wrote: > On Tue, 22 Dec 2015 17:32:30 +0100 Vitaly Kuznetsov <[email protected]> > wrote: > > > Currently, all newly added memory blocks remain in 'offline' state unless > > someone onlines them, some linux distributions carry special udev rules > > like: > > > > SUBSYSTEM=="memory", ACTION=="add", ATTR{state}=="offline", > > ATTR{state}="online" > > > > to make this happen automatically. This is not a great solution for virtual > > machines where memory hotplug is being used to address high memory pressure > > situations as such onlining is slow and a userspace process doing this > > (udev) has a chance of being killed by the OOM killer as it will probably > > require to allocate some memory. > > > > Introduce default policy for the newly added memory blocks in > > /sys/devices/system/memory/hotplug_autoonline file with two possible > > values: "offline" which preserves the current behavior and "online" which > > causes all newly added memory blocks to go online as soon as they're added. > > The default is "online" when MEMORY_HOTPLUG_AUTOONLINE kernel config option > > is selected. > > I think the default should be "offline" so vendors can ship kernels > which have CONFIG_MEMORY_HOTPLUG_AUTOONLINE=y while being > back-compatible with previous kernels. >
But isn't the premise of the changelog that this is currently being handled by the distribution? Perhaps I don't understand why this patch can't end up just introducing a sysfs tunable that is always present and can be set by initscripts of that distribution. I'd also suggest that hotplug_autoonline be renamed to auto_online_block. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
