On Tue, May 07, 2019 at 08:38:00PM +0200, David Hildenbrand wrote:
>Only memory to be added to the buddy and to be onlined/offlined by
>user space using memory block devices needs (and should have!) memory
>block devices.
>
>Factor out creation of memory block devices Create all devices after
>arch_add_memory() succeeded. We can later drop the want_memblock parameter,
>because it is now effectively stale.
>
>Only after memory block devices have been added, memory can be onlined
>by user space. This implies, that memory is not visible to user space at
>all before arch_add_memory() succeeded.
>
>Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
>Cc: David Hildenbrand <david@xxxxxxxxxx>
>Cc: "mike.travis@xxxxxxx" <mike.travis@xxxxxxx>
>Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>Cc: Ingo Molnar <mingo@xxxxxxxxxx>
>Cc: Andrew Banman <andrew.banman@xxxxxxx>
>Cc: Oscar Salvador <osalvador@xxxxxxx>
>Cc: Michal Hocko <mhocko@xxxxxxxx>
>Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
>Cc: Qian Cai <cai@xxxxxx>
>Cc: Wei Yang <richard.weiyang@xxxxxxxxx>
>Cc: Arun KS <arunks@xxxxxxxxxxxxxx>
>Cc: Mathieu Malaterre <malat@xxxxxxxxxx>
>Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
>---
> drivers/base/memory.c | 70 ++++++++++++++++++++++++++----------------
> include/linux/memory.h | 2 +-
> mm/memory_hotplug.c | 15 ++++-----
> 3 files changed, 53 insertions(+), 34 deletions(-)
>
>diff --git a/drivers/base/memory.c b/drivers/base/memory.c
>index 6e0cb4fda179..862c202a18ca 100644
>--- a/drivers/base/memory.c
>+++ b/drivers/base/memory.c
>@@ -701,44 +701,62 @@ static int add_memory_block(int base_section_nr)
> return 0;
> }
>
>+static void unregister_memory(struct memory_block *memory)
>+{
>+ BUG_ON(memory->dev.bus != &memory_subsys);
>+
>+ /* drop the ref. we got via find_memory_block() */
>+ put_device(&memory->dev);
>+ device_unregister(&memory->dev);
>+}
>+
> /*
>- * need an interface for the VM to add new memory regions,
>- * but without onlining it.
>+ * Create memory block devices for the given memory area. Start and size
>+ * have to be aligned to memory block granularity. Memory block devices
>+ * will be initialized as offline.
> */
>-int hotplug_memory_register(int nid, struct mem_section *section)
>+int hotplug_memory_register(unsigned long start, unsigned long size)
> {
>- int ret = 0;
>+ unsigned long block_nr_pages = memory_block_size_bytes() >> PAGE_SHIFT;
>+ unsigned long start_pfn = PFN_DOWN(start);
>+ unsigned long end_pfn = start_pfn + (size >> PAGE_SHIFT);
>+ unsigned long pfn;
> struct memory_block *mem;
>+ int ret = 0;
>
>- mutex_lock(&mem_sysfs_mutex);
>+ BUG_ON(!IS_ALIGNED(start, memory_block_size_bytes()));
>+ BUG_ON(!IS_ALIGNED(size, memory_block_size_bytes()));
After this change, the call flow looks like this:
add_memory_resource
check_hotplug_memory_range
hotplug_memory_register
Since in check_hotplug_memory_range() has checked the boundary, do we need to
check here again?
--
Wei Yang
Help you, Help me
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