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. > > thanks, > > greg k-h
