Re: [PATCH v3 3/7] mm/memory_hotplug: prepare passing flags to add_memory() and friends

[Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>]

> We soon want to pass flags, e.g., to mark added System RAM resources.
> mergeable. Prepare for that.
>
> This patch is based on a similar patch by Oscar Salvador:
>
> https://lkml.kernel.org/r/20190625075227.15193-3-osalvador@xxxxxxx
>
> Acked-by: Wei Liu <wei.liu@xxxxxxxxxx>
> Reviewed-by: Juergen Gross <jgross@xxxxxxxx> # Xen related part
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxx>
> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> Cc: Jason Gunthorpe <jgg@xxxxxxxx>
> Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>
> Cc: Baoquan He <bhe@xxxxxxxxxx>
> Cc: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> Cc: Paul Mackerras <paulus@xxxxxxxxx>
> Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
> Cc: Len Brown <lenb@xxxxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx>
> Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
> Cc: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>
> Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
> Cc: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
> Cc: Wei Liu <wei.liu@xxxxxxxxxx>
> Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
> Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> Cc: David Hildenbrand <david@xxxxxxxxxx>
> Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
> Cc: Jason Wang <jasowang@xxxxxxxxxx>
> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> Cc: Juergen Gross <jgross@xxxxxxxx>
> Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> Cc: "Oliver O'Halloran" <oohall@xxxxxxxxx>
> Cc: Pingfan Liu <kernelfans@xxxxxxxxx>
> Cc: Nathan Lynch <nathanl@xxxxxxxxxxxxx>
> Cc: Libor Pechacek <lpechacek@xxxxxxx>
> Cc: Anton Blanchard <anton@xxxxxxxxxx>
> Cc: Leonardo Bras <leobras.c@xxxxxxxxx>
> Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
> Cc: linux-acpi@xxxxxxxxxxxxxxx
> Cc: linux-nvdimm@xxxxxxxxxxxx
> Cc: linux-hyperv@xxxxxxxxxxxxxxx
> Cc: linux-s390@xxxxxxxxxxxxxxx
> Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
> Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx
> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
> ---
>  arch/powerpc/platforms/powernv/memtrace.c       |  2 +-
>  arch/powerpc/platforms/pseries/hotplug-memory.c |  2 +-
>  drivers/acpi/acpi_memhotplug.c                  |  3 ++-
>  drivers/base/memory.c                           |  3 ++-
>  drivers/dax/kmem.c                              |  2 +-
>  drivers/hv/hv_balloon.c                         |  2 +-
>  drivers/s390/char/sclp_cmd.c                    |  2 +-
>  drivers/virtio/virtio_mem.c                     |  2 +-
>  drivers/xen/balloon.c                           |  2 +-
>  include/linux/memory_hotplug.h                  | 16 ++++++++++++----
>  mm/memory_hotplug.c                             | 14 +++++++-------
>  11 files changed, 30 insertions(+), 20 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/memtrace.c 
> b/arch/powerpc/platforms/powernv/memtrace.c
> index 13b369d2cc454..6828108486f83 100644
> --- a/arch/powerpc/platforms/powernv/memtrace.c
> +++ b/arch/powerpc/platforms/powernv/memtrace.c
> @@ -224,7 +224,7 @@ static int memtrace_online(void)
>                         ent->mem = 0;
>                 }
>
> -               if (add_memory(ent->nid, ent->start, ent->size)) {
> +               if (add_memory(ent->nid, ent->start, ent->size, MHP_NONE)) {
>                         pr_err("Failed to add trace memory to node %d\n",
>                                 ent->nid);
>                         ret += 1;
> diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c 
> b/arch/powerpc/platforms/pseries/hotplug-memory.c
> index 0ea976d1cac47..e1c9fa0d730f5 100644
> --- a/arch/powerpc/platforms/pseries/hotplug-memory.c
> +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
> @@ -615,7 +615,7 @@ static int dlpar_add_lmb(struct drmem_lmb *lmb)
>         nid = memory_add_physaddr_to_nid(lmb->base_addr);
>
>         /* Add the memory */
> -       rc = __add_memory(nid, lmb->base_addr, block_sz);
> +       rc = __add_memory(nid, lmb->base_addr, block_sz, MHP_NONE);
>         if (rc) {
>                 invalidate_lmb_associativity_index(lmb);
>                 return rc;
> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
> index e294f44a78504..2067c3bc55763 100644
> --- a/drivers/acpi/acpi_memhotplug.c
> +++ b/drivers/acpi/acpi_memhotplug.c
> @@ -207,7 +207,8 @@ static int acpi_memory_enable_device(struct 
> acpi_memory_device *mem_device)
>                 if (node < 0)
>                         node = memory_add_physaddr_to_nid(info->start_addr);
>
> -               result = __add_memory(node, info->start_addr, info->length);
> +               result = __add_memory(node, info->start_addr, info->length,
> +                                     MHP_NONE);
>
>                 /*
>                  * If the memory block has been used by the kernel, 
> add_memory()
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index 4db3c660de831..b4c297dd04755 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -432,7 +432,8 @@ static ssize_t probe_store(struct device *dev, struct 
> device_attribute *attr,
>
>         nid = memory_add_physaddr_to_nid(phys_addr);
>         ret = __add_memory(nid, phys_addr,
> -                          MIN_MEMORY_BLOCK_SIZE * sections_per_block);
> +                          MIN_MEMORY_BLOCK_SIZE * sections_per_block,
> +                          MHP_NONE);
>
>         if (ret)
>                 goto out;
> diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
> index 7dcb2902e9b1b..896cb9444e727 100644
> --- a/drivers/dax/kmem.c
> +++ b/drivers/dax/kmem.c
> @@ -95,7 +95,7 @@ int dev_dax_kmem_probe(struct dev_dax *dev_dax)
>                  * this as RAM automatically.
>                  */
>                 rc = add_memory_driver_managed(numa_node, range.start,
> -                               range_len(&range), kmem_name);
> +                               range_len(&range), kmem_name, MHP_NONE);
>
>                 res->flags |= IORESOURCE_BUSY;
>                 if (rc) {
> diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
> index 32e3bc0aa665a..3c0d52e244520 100644
> --- a/drivers/hv/hv_balloon.c
> +++ b/drivers/hv/hv_balloon.c
> @@ -726,7 +726,7 @@ static void hv_mem_hot_add(unsigned long start, unsigned 
> long size,
>
>                 nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn));
>                 ret = add_memory(nid, PFN_PHYS((start_pfn)),
> -                               (HA_CHUNK << PAGE_SHIFT));
> +                               (HA_CHUNK << PAGE_SHIFT), MHP_NONE);
>
>                 if (ret) {
>                         pr_err("hot_add memory failed error is %d\n", ret);
> diff --git a/drivers/s390/char/sclp_cmd.c b/drivers/s390/char/sclp_cmd.c
> index a864b21af602a..f6e97f0830f64 100644
> --- a/drivers/s390/char/sclp_cmd.c
> +++ b/drivers/s390/char/sclp_cmd.c
> @@ -406,7 +406,7 @@ static void __init add_memory_merged(u16 rn)
>         if (!size)
>                 goto skip_add;
>         for (addr = start; addr < start + size; addr += block_size)
> -               add_memory(0, addr, block_size);
> +               add_memory(0, addr, block_size, MHP_NONE);
>  skip_add:
>         first_rn = rn;
>         num = 1;
> diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
> index 834b7c13ef3dc..ed99e43354010 100644
> --- a/drivers/virtio/virtio_mem.c
> +++ b/drivers/virtio/virtio_mem.c
> @@ -424,7 +424,7 @@ static int virtio_mem_mb_add(struct virtio_mem *vm, 
> unsigned long mb_id)
>
>         dev_dbg(&vm->vdev->dev, "adding memory block: %lu\n", mb_id);
>         return add_memory_driver_managed(nid, addr, memory_block_size_bytes(),
> -                                        vm->resource_name);
> +                                        vm->resource_name, MHP_NONE);
>  }
>
>  /*
> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
> index 51427c752b37b..9f40a294d398d 100644
> --- a/drivers/xen/balloon.c
> +++ b/drivers/xen/balloon.c
> @@ -331,7 +331,7 @@ static enum bp_state reserve_additional_memory(void)
>         mutex_unlock(&balloon_mutex);
>         /* add_memory_resource() requires the device_hotplug lock */
>         lock_device_hotplug();
> -       rc = add_memory_resource(nid, resource);
> +       rc = add_memory_resource(nid, resource, MHP_NONE);
>         unlock_device_hotplug();
>         mutex_lock(&balloon_mutex);
>
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index 51a877fec8da8..e53d1058f3443 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -57,6 +57,12 @@ enum {
>         MMOP_ONLINE_MOVABLE,
>  };
>
> +/* Flags for add_memory() and friends to specify memory hotplug details. */
> +typedef int __bitwise mhp_t;
> +
> +/* No special request */
> +#define MHP_NONE               ((__force mhp_t)0)
> +
>  /*
>   * Extended parameters for memory hotplug:
>   * altmap: alternative allocator for memmap array (optional)
> @@ -345,11 +351,13 @@ extern void set_zone_contiguous(struct zone *zone);
>  extern void clear_zone_contiguous(struct zone *zone);
>
>  extern void __ref free_area_init_core_hotplug(int nid);
> -extern int __add_memory(int nid, u64 start, u64 size);
> -extern int add_memory(int nid, u64 start, u64 size);
> -extern int add_memory_resource(int nid, struct resource *resource);
> +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);
>  extern int add_memory_driver_managed(int nid, u64 start, u64 size,
> -                                    const char *resource_name);
> +                                    const char *resource_name,
> +                                    mhp_t mhp_flags);
>  extern void move_pfn_range_to_zone(struct zone *zone, unsigned long 
> start_pfn,
>                                    unsigned long nr_pages,
>                                    struct vmem_altmap *altmap, int 
> migratetype);
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 8e1cd18b5cf14..8f0bd7c9a63a5 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1039,7 +1039,7 @@ static int online_memory_block(struct memory_block 
> *mem, void *arg)
>   *
>   * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
>   */
> -int __ref add_memory_resource(int nid, struct resource *res)
> +int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
>  {
>         struct mhp_params params = { .pgprot = PAGE_KERNEL };
>         u64 start, size;
> @@ -1118,7 +1118,7 @@ int __ref add_memory_resource(int nid, struct resource 
> *res)
>  }
>
>  /* requires device_hotplug_lock, see add_memory_resource() */
> -int __ref __add_memory(int nid, u64 start, u64 size)
> +int __ref __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
>  {
>         struct resource *res;
>         int ret;
> @@ -1127,18 +1127,18 @@ int __ref __add_memory(int nid, u64 start, u64 size)
>         if (IS_ERR(res))
>                 return PTR_ERR(res);
>
> -       ret = add_memory_resource(nid, res);
> +       ret = add_memory_resource(nid, res, mhp_flags);
>         if (ret < 0)
>                 release_memory_resource(res);
>         return ret;
>  }
>
> -int add_memory(int nid, u64 start, u64 size)
> +int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
>  {
>         int rc;
>
>         lock_device_hotplug();
> -       rc = __add_memory(nid, start, size);
> +       rc = __add_memory(nid, start, size, mhp_flags);
>         unlock_device_hotplug();
>
>         return rc;
> @@ -1167,7 +1167,7 @@ EXPORT_SYMBOL_GPL(add_memory);
>   * "System RAM ($DRIVER)".
>   */
>  int add_memory_driver_managed(int nid, u64 start, u64 size,
> -                             const char *resource_name)
> +                             const char *resource_name, mhp_t mhp_flags)
>  {
>         struct resource *res;
>         int rc;
> @@ -1185,7 +1185,7 @@ int add_memory_driver_managed(int nid, u64 start, u64 
> size,
>                 goto out_unlock;
>         }
>
> -       rc = add_memory_resource(nid, res);
> +       rc = add_memory_resource(nid, res, mhp_flags);
>         if (rc < 0)
>                 release_memory_resource(res);
>
> --

Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>

> 2.26.2
>