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@redhat.com
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@linux.alibaba.com Cc: "Michael S. Tsirkin" mst@redhat.com Cc: Jason Wang jasowang@redhat.com Cc: Pankaj Gupta pankaj.gupta.linux@gmail.com Cc: Michal Hocko mhocko@kernel.org Cc: Oscar Salvador osalvador@suse.de Cc: Wei Yang richard.weiyang@linux.alibaba.com Cc: Andrew Morton akpm@linux-foundation.org Signed-off-by: David Hildenbrand david@redhat.com Link: https://lore.kernel.org/r/20201112133815.13332-28-david@redhat.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Acked-by: Andrew Morton akpm@linux-foundation.org
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@huawei.com
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