Existing callers of add_memory_driver_managed cannot select the preferred online type (ZONE_NORMAL vs ZONE_MOVABLE), requiring it to hot-add memory as offline blocks, and then follow up by onlining each memory block individually.
Most drivers prefer the system default, but the CXL driver wants to plumb a preferred policy through the dax kmem driver. Refactor APIs to add a new interface which allows the dax kmem and cxl_core modules to select a preferred policy. Only expose this interface to those modules to avoid confusion among existing API users and to limit usage in out-of-tree modules. Refactor add_memory_driver_managed, extract __add_memory_driver_managed - Add proper kernel-doc for add_memory_driver_managed while refactoring - New helper accepts an explicit online_type. - New help validates online_type is between OFFLINE and ONLINE_MOVABLE Refactor: add_memory_resource, extract __add_memory_resource - new helper accepts an explicit online_type Original APIs now explicitly pass the system-default to new helpers. No functional change for existing users. Cc: David Hildenbrand <[email protected]> Cc: Oscar Salvador <[email protected]> Cc: Andrew Morton <[email protected]> Signed-off-by: Gregory Price <[email protected]> --- include/linux/memory_hotplug.h | 3 ++ mm/memory_hotplug.c | 60 +++++++++++++++++++++++++++++----- 2 files changed, 55 insertions(+), 8 deletions(-) diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index a8bcb36f93b8..1f19f08552ea 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -320,6 +320,9 @@ extern int __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags); extern int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags); extern int add_memory_resource(int nid, struct resource *resource, mhp_t mhp_flags); +int __add_memory_driver_managed(int nid, u64 start, u64 size, + const char *resource_name, mhp_t mhp_flags, + enum mmop online_type); extern int add_memory_driver_managed(int nid, u64 start, u64 size, const char *resource_name, mhp_t mhp_flags); diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index af9a6cb5a2f9..9081aad5078f 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1492,10 +1492,10 @@ static int create_altmaps_and_memory_blocks(int nid, struct memory_group *group, * * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ -int add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) +static int __add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags, + enum mmop online_type) { struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) }; - enum mmop online_type = mhp_get_default_online_type(); enum memblock_flags memblock_flags = MEMBLOCK_NONE; struct memory_group *group = NULL; u64 start, size; @@ -1583,7 +1583,7 @@ int add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) merge_system_ram_resource(res); /* online pages if requested */ - if (mhp_get_default_online_type() != MMOP_OFFLINE) + if (online_type != MMOP_OFFLINE) walk_memory_blocks(start, size, &online_type, online_memory_block); @@ -1601,7 +1601,13 @@ int add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) return ret; } -/* requires device_hotplug_lock, see add_memory_resource() */ +int add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) +{ + return __add_memory_resource(nid, res, mhp_flags, + mhp_get_default_online_type()); +} + +/* requires device_hotplug_lock, see __add_memory_resource() */ int __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags) { struct resource *res; @@ -1629,7 +1635,15 @@ int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags) } EXPORT_SYMBOL_GPL(add_memory); -/* +/** + * __add_memory_driver_managed - add driver-managed memory with explicit online_type + * @nid: NUMA node ID where the memory will be added + * @start: Start physical address of the memory range + * @size: Size of the memory range in bytes + * @resource_name: Resource name in format "System RAM ($DRIVER)" + * @mhp_flags: Memory hotplug flags + * @online_type: Auto-Online behavior (offline, online, kernel, movable) + * * Add special, driver-managed memory to the system as system RAM. Such * memory is not exposed via the raw firmware-provided memmap as system * RAM, instead, it is detected and added by a driver - during cold boot, @@ -1649,9 +1663,12 @@ EXPORT_SYMBOL_GPL(add_memory); * * The resource_name (visible via /proc/iomem) has to have the format * "System RAM ($DRIVER)". + * + * Return: 0 on success, negative error code on failure. */ -int add_memory_driver_managed(int nid, u64 start, u64 size, - const char *resource_name, mhp_t mhp_flags) +int __add_memory_driver_managed(int nid, u64 start, u64 size, + const char *resource_name, mhp_t mhp_flags, + enum mmop online_type) { struct resource *res; int rc; @@ -1661,6 +1678,9 @@ int add_memory_driver_managed(int nid, u64 start, u64 size, resource_name[strlen(resource_name) - 1] != ')') return -EINVAL; + if (online_type < MMOP_OFFLINE || online_type > MMOP_ONLINE_MOVABLE) + return -EINVAL; + lock_device_hotplug(); res = register_memory_resource(start, size, resource_name); @@ -1669,7 +1689,7 @@ int add_memory_driver_managed(int nid, u64 start, u64 size, goto out_unlock; } - rc = add_memory_resource(nid, res, mhp_flags); + rc = __add_memory_resource(nid, res, mhp_flags, online_type); if (rc < 0) release_memory_resource(res); @@ -1677,6 +1697,30 @@ int add_memory_driver_managed(int nid, u64 start, u64 size, unlock_device_hotplug(); return rc; } +EXPORT_SYMBOL_FOR_MODULES(__add_memory_driver_managed, "kmem,cxl_core"); + +/** + * add_memory_driver_managed - add driver-managed memory + * @nid: NUMA node ID where the memory will be added + * @start: Start physical address of the memory range + * @size: Size of the memory range in bytes + * @resource_name: Resource name in format "System RAM ($DRIVER)" + * @mhp_flags: Memory hotplug flags + * + * Add driver-managed memory with the system default online type set by + * build config or kernel boot parameter. + * + * See __add_memory_driver_managed for more details. + * + * Return: 0 on success, negative error code on failure. + */ +int add_memory_driver_managed(int nid, u64 start, u64 size, + const char *resource_name, mhp_t mhp_flags) +{ + return __add_memory_driver_managed(nid, start, size, resource_name, + mhp_flags, + mhp_get_default_online_type()); +} EXPORT_SYMBOL_GPL(add_memory_driver_managed); /* -- 2.53.0
