Messages in this thread | | | Date | Wed, 13 Jul 2022 12:01:13 +0200 | Subject | Re: [PATCH v7 04/14] mm/shmem: Support memfile_notifier | From | "Gupta, Pankaj" <> |
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>>> +#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?
Thanks, Pankaj
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