Messages in this thread | | | Date | Thu, 14 Jul 2022 07:49:03 +0800 | From | Chao Peng <> | Subject | Re: [PATCH v7 04/14] mm/shmem: Support memfile_notifier |
| |
On Wed, Jul 13, 2022 at 12:01:13PM +0200, Gupta, Pankaj wrote: > > > > > +#ifdef CONFIG_MIGRATION > > > > +static int shmem_migrate_page(struct address_space *mapping, > > > > + struct page *newpage, struct page *page, > > > > + enum migrate_mode mode) > > > > +{ > > > > + struct inode *inode = mapping->host; > > > > + struct shmem_inode_info *info = SHMEM_I(inode); > > > > + > > > > + if (info->memfile_node.flags & MEMFILE_F_UNMOVABLE) > > > > + return -EOPNOTSUPP; > > > > + return migrate_page(mapping, newpage, page, mode); > > > > > > Wondering how well page migrate would work for private pages > > > on shmem memfd based backend? > > > > From high level: > > - KVM unset MEMFILE_F_UNMOVABLE bit to indicate it capable of > > migrating a page. > > - Introduce new 'migrate' callback(s) to memfile_notifier_ops for KVM > > to register. > > - The callback is hooked to migrate_page() here. > > - Once page migration requested, shmem calls into the 'migrate' > > callback(s) to perform additional steps for encrypted memory (For > > TDX we will call TDH.MEM.PAGE.RELOCATE). > > Yes, that would require additional (protocol specific) handling for private > pages. Was trying to find where "MEMFILE_F_UNMOVABLE" flag is set currently?
It's set with memfile_register_notifier() in patch 13.
> > Thanks, > Pankaj
| |