This looks fine except for a few nitpicks below:
> }
>
> + dev_pagemap_enable_ops();
> pgmap->type = MEMORY_DEVICE_FS_DAX;
> pgmap->page_free = generic_dax_pagefree;
> pgmap->data = owner;
> @@ -215,6 +216,7 @@ void fs_dax_release(struct dax_device *dax_dev, void *owner)
> pgmap->type = MEMORY_DEVICE_HOST;
> pgmap->page_free = NULL;
> pgmap->data = NULL;
> + dev_pagemap_disable_ops();
should these be get/put instead of enable/disable given that they
implement a refcount?
> +#ifdef CONFIG_DEV_PAGEMAP_OPS
> +void __put_devmap_managed_page(struct page *page);
> +DECLARE_STATIC_KEY_FALSE(devmap_managed_key);
> +static inline bool put_devmap_managed_page(struct page *page)
> {
> + if (!static_branch_unlikely(&devmap_managed_key))
> + return false;
> + if (!is_zone_device_page(page))
> + return false;
> + switch (page->pgmap->type) {
> + case MEMORY_DEVICE_PRIVATE:
> + case MEMORY_DEVICE_PUBLIC:
> + case MEMORY_DEVICE_FS_DAX:
> + __put_devmap_managed_page(page);
> + return true;
> + default:
> + break;
> + }
> + return false;
Should the switch be moved into the out of line version to keep
the inline instructions at a minimum?
> + * pages go idle.
> + */
> +void dev_pagemap_enable_ops(void)
> +{
> + if (atomic_inc_return(&devmap_enable) == 1)
> + static_branch_enable(&devmap_managed_key);
> +}
> +EXPORT_SYMBOL(dev_pagemap_enable_ops);
_GPL?
> +EXPORT_SYMBOL(dev_pagemap_disable_ops);
Same.
