On 2023/6/19 14:20, Greg KH wrote: > On Wed, Jun 14, 2023 at 02:45:58PM +0800, mawupeng wrote: >> >> >> On 2023/6/14 14:35, Greg KH wrote: >>> On Wed, Jun 14, 2023 at 02:19:00PM +0800, Wupeng Ma wrote: >>>> From: David Hildenbrand <david@xxxxxxxxxx> >>>> >>>> virtio-mem soon wants to use offline_and_remove_memory() memory that >>>> exceeds a single Linux memory block (memory_block_size_bytes()). Let's >>>> remove that restriction. >>>> >>>> Let's remember the old state and try to restore that if anything goes >>>> wrong. While re-onlining can, in general, fail, it's highly unlikely to >>>> happen (usually only when a notifier fails to allocate memory, and these >>>> are rather rare). >>>> >>>> This will be used by virtio-mem to offline+remove memory ranges that are >>>> bigger than a single memory block - for example, with a device block >>>> size of 1 GiB (e.g., gigantic pages in the hypervisor) and a Linux memory >>>> block size of 128MB. >>>> >>>> While we could compress the state into 2 bit, using 8 bit is much >>>> easier. >>>> >>>> This handling is similar, but different to acpi_scan_try_to_offline(): >>>> >>>> a) We don't try to offline twice. I am not sure if this CONFIG_MEMCG >>>> optimization is still relevant - it should only apply to ZONE_NORMAL >>>> (where we have no guarantees). If relevant, we can always add it. >>>> >>>> b) acpi_scan_try_to_offline() simply onlines all memory in case >>>> something goes wrong. It doesn't restore previous online type. Let's do >>>> that, so we won't overwrite what e.g., user space configured. >>>> >>>> Reviewed-by: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx> >>>> Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx> >>>> Cc: Jason Wang <jasowang@xxxxxxxxxx> >>>> Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx> >>>> Cc: Michal Hocko <mhocko@xxxxxxxxxx> >>>> Cc: Oscar Salvador <osalvador@xxxxxxx> >>>> Cc: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx> >>>> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> >>>> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> >>>> Link: https://lore.kernel.org/r/20201112133815.13332-28-david@xxxxxxxxxx >>>> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> >>>> Acked-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> >>>> --- >>>> mm/memory_hotplug.c | 105 +++++++++++++++++++++++++++++++++++++------- >>>> 1 file changed, 89 insertions(+), 16 deletions(-) >>> >>> As you forwarded this patch on, you too need to sign-off on it. >> >> Thanks for reminding me. >> >> Signed-off-by: Ma Wupeng <mawupeng1@xxxxxxxxxx> >> >>> >>> Also, what is the git id of the commit in Linus's tree? >> >> Sorry, here is the commit in Linus's tree. >> >> commit 8dc4bb58a146655eb057247d7c9d19e73928715b upstream. > > Please resend the change with both of these things fixed up, so I don't > have to manually do it :) I have resend the patch but use the parent message id for in-reply-to. Sorry. > > thanks, > > greg k-h
