Vishal Verma <vishal.l.ve...@intel.com> writes: > The MHP_MEMMAP_ON_MEMORY flag for hotplugged memory is currently > restricted to 'memblock_size' chunks of memory being added. Adding a > larger span of memory precludes memmap_on_memory semantics. > > For users of hotplug such as kmem, large amounts of memory might get > added from the CXL subsystem. In some cases, this amount may exceed the > available 'main memory' to store the memmap for the memory being added. > In this case, it is useful to have a way to place the memmap on the > memory being added, even if it means splitting the addition into > memblock-sized chunks. > > Change add_memory_resource() to loop over memblock-sized chunks of > memory if caller requested memmap_on_memory, and if other conditions for > it are met,. Teach try_remove_memory() to also expect that a memory > range being removed might have been split up into memblock sized chunks, > and to loop through those as needed. >
This conflicts with https://lore.kernel.org/linux-mm/20230718024409.95742-1-aneesh.ku...@linux.ibm.com/ IIUC Andrew was planning add that series to -mm. Also that patchset makes some of related changes in this patch not required. Can you rebase this series on top of that ? > > Cc: Andrew Morton <a...@linux-foundation.org> > Cc: David Hildenbrand <da...@redhat.com> > Cc: Oscar Salvador <osalva...@suse.de> > Cc: Dan Williams <dan.j.willi...@intel.com> > Cc: Dave Jiang <dave.ji...@intel.com> > Cc: Dave Hansen <dave.han...@linux.intel.com> > Cc: Huang Ying <ying.hu...@intel.com> > Suggested-by: David Hildenbrand <da...@redhat.com> > Signed-off-by: Vishal Verma <vishal.l.ve...@intel.com> > --- > mm/memory_hotplug.c | 154 > +++++++++++++++++++++++++++++++--------------------- > 1 file changed, 91 insertions(+), 63 deletions(-) > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index e9bcacbcbae2..20456f0d28e6 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -1286,6 +1286,35 @@ bool mhp_supports_memmap_on_memory(unsigned long size) > } > EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory); > > +static int add_memory_create_devices(int nid, struct memory_group *group, > + u64 start, u64 size, mhp_t mhp_flags) > +{ > + struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) }; > + struct vmem_altmap mhp_altmap = {}; > + int ret; > + > + if ((mhp_flags & MHP_MEMMAP_ON_MEMORY)) { > + mhp_altmap.free = PHYS_PFN(size); > + mhp_altmap.base_pfn = PHYS_PFN(start); > + params.altmap = &mhp_altmap; > + } > + > + /* call arch's memory hotadd */ > + ret = arch_add_memory(nid, start, size, ¶ms); > + if (ret < 0) > + return ret; > + > + /* create memory block devices after memory was added */ > + ret = create_memory_block_devices(start, size, mhp_altmap.alloc, > + group); > + if (ret) { > + arch_remove_memory(start, size, NULL); > + return ret; > + } > + > + return 0; > +} > + > /* > * NOTE: The caller must call lock_device_hotplug() to serialize hotplug > * and online/offline operations (triggered e.g. by sysfs). > @@ -1294,11 +1323,10 @@ EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory); > */ > int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) > { > - struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) }; > + unsigned long memblock_size = memory_block_size_bytes(); > enum memblock_flags memblock_flags = MEMBLOCK_NONE; > - struct vmem_altmap mhp_altmap = {}; > struct memory_group *group = NULL; > - u64 start, size; > + u64 start, size, cur_start; > bool new_node = false; > int ret; > > @@ -1339,27 +1367,20 @@ int __ref add_memory_resource(int nid, struct > resource *res, mhp_t mhp_flags) > /* > * Self hosted memmap array > */ > - if (mhp_flags & MHP_MEMMAP_ON_MEMORY) { > - if (!mhp_supports_memmap_on_memory(size)) { > - ret = -EINVAL; > + if ((mhp_flags & MHP_MEMMAP_ON_MEMORY) && > + mhp_supports_memmap_on_memory(memblock_size)) { > + for (cur_start = start; cur_start < start + size; > + cur_start += memblock_size) { > + ret = add_memory_create_devices(nid, group, cur_start, > + memblock_size, > + mhp_flags); > + if (ret) > + goto error; > + } > + } else { > + ret = add_memory_create_devices(nid, group, start, size, > mhp_flags); > + if (ret) > goto error; > - } > - mhp_altmap.free = PHYS_PFN(size); > - mhp_altmap.base_pfn = PHYS_PFN(start); > - params.altmap = &mhp_altmap; > - } > - > - /* call arch's memory hotadd */ > - ret = arch_add_memory(nid, start, size, ¶ms); > - if (ret < 0) > - goto error; > - > - /* create memory block devices after memory was added */ > - ret = create_memory_block_devices(start, size, mhp_altmap.alloc, > - group); > - if (ret) { > - arch_remove_memory(start, size, NULL); > - goto error; > } > > if (new_node) { > @@ -2035,12 +2056,38 @@ void try_offline_node(int nid) > } > EXPORT_SYMBOL(try_offline_node); > > -static int __ref try_remove_memory(u64 start, u64 size) > +static void __ref __try_remove_memory(int nid, u64 start, u64 size, > + struct vmem_altmap *altmap) > { > - struct vmem_altmap mhp_altmap = {}; > - struct vmem_altmap *altmap = NULL; > - unsigned long nr_vmemmap_pages; > - int rc = 0, nid = NUMA_NO_NODE; > + /* remove memmap entry */ > + firmware_map_remove(start, start + size, "System RAM"); > + > + /* > + * Memory block device removal under the device_hotplug_lock is > + * a barrier against racing online attempts. > + */ > + remove_memory_block_devices(start, size); > + > + mem_hotplug_begin(); > + > + arch_remove_memory(start, size, altmap); > + > + if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) { > + memblock_phys_free(start, size); > + memblock_remove(start, size); > + } > + > + release_mem_region_adjustable(start, size); > + > + if (nid != NUMA_NO_NODE) > + try_offline_node(nid); > + > + mem_hotplug_done(); > +} > + > +static int try_remove_memory(u64 start, u64 size) > +{ > + int rc, nid = NUMA_NO_NODE; > > BUG_ON(check_hotplug_memory_range(start, size)); > > @@ -2058,20 +2105,21 @@ static int __ref try_remove_memory(u64 start, u64 > size) > return rc; > > /* > - * We only support removing memory added with MHP_MEMMAP_ON_MEMORY in > - * the same granularity it was added - a single memory block. > + * For memmap_on_memory, the altmaps could have been added on > + * a per-memblock basis. Loop through the entire range if so, > + * and remove each memblock and its altmap > */ > if (mhp_memmap_on_memory()) { > - nr_vmemmap_pages = walk_memory_blocks(start, size, NULL, > - get_nr_vmemmap_pages_cb); > - if (nr_vmemmap_pages) { > - if (size != memory_block_size_bytes()) { > - pr_warn("Refuse to remove %#llx - %#llx," > - "wrong granularity\n", > - start, start + size); > - return -EINVAL; > - } > + unsigned long memblock_size = memory_block_size_bytes(); > + struct vmem_altmap mhp_altmap = {}; > + struct vmem_altmap *altmap; > + u64 cur_start; > > + for (cur_start = start; cur_start < start + size; > + cur_start += memblock_size) { > + unsigned long nr_vmemmap_pages = > + walk_memory_blocks(start, memblock_size, NULL, > + get_nr_vmemmap_pages_cb); > /* > * Let remove_pmd_table->free_hugepage_table do the > * right thing if we used vmem_altmap when hot-adding > @@ -2079,33 +2127,13 @@ static int __ref try_remove_memory(u64 start, u64 > size) > */ > mhp_altmap.alloc = nr_vmemmap_pages; > altmap = &mhp_altmap; > + __try_remove_memory(nid, cur_start, memblock_size, > + altmap); > } > + } else { > + __try_remove_memory(nid, start, size, NULL); > } > > - /* remove memmap entry */ > - firmware_map_remove(start, start + size, "System RAM"); > - > - /* > - * Memory block device removal under the device_hotplug_lock is > - * a barrier against racing online attempts. > - */ > - remove_memory_block_devices(start, size); > - > - mem_hotplug_begin(); > - > - arch_remove_memory(start, size, altmap); > - > - if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) { > - memblock_phys_free(start, size); > - memblock_remove(start, size); > - } > - > - release_mem_region_adjustable(start, size); > - > - if (nid != NUMA_NO_NODE) > - try_offline_node(nid); > - > - mem_hotplug_done(); > return 0; > } > > > -- > 2.41.0
