Thread (32 messages) 32 messages, 4 authors, 2023-08-08

Re: [PATCH v7 6/7] mm/memory_hotplug: Embed vmem_altmap details in memory block

From: "Verma, Vishal L" <vishal.l.verma@intel.com>
Date: 2023-08-01 23:10:26
Also in: linux-mm

On Tue, 2023-08-01 at 10:11 +0530, Aneesh Kumar K.V wrote:
With memmap on memory, some architecture needs more details w.r.t altmap
such as base_pfn, end_pfn, etc to unmap vmemmap memory. Instead of
computing them again when we remove a memory block, embed vmem_altmap
details in struct memory_block if we are using memmap on memory block
feature.

Acked-by: David Hildenbrand <redacted>
Signed-off-by: Aneesh Kumar K.V <redacted>
---
 drivers/base/memory.c  | 27 +++++++++++++--------
 include/linux/memory.h |  8 ++----
 mm/memory_hotplug.c    | 55 ++++++++++++++++++++++++++----------------
 3 files changed, 53 insertions(+), 37 deletions(-)
<snip>
quoted hunk ↗ jump to hunk
@@ -2136,10 +2148,10 @@ EXPORT_SYMBOL(try_offline_node);
 
 static int __ref try_remove_memory(u64 start, u64 size)
 {
-       struct vmem_altmap mhp_altmap = {};
-       struct vmem_altmap *altmap = NULL;
-       unsigned long nr_vmemmap_pages;
+       int ret;
Minor nit - there is already an 'int rc' below - just use that, or
rename it to 'ret' if that's better for consistency.
quoted hunk ↗ jump to hunk
+       struct memory_block *mem;
        int rc = 0, nid = NUMA_NO_NODE;
+       struct vmem_altmap *altmap = NULL;
 
        BUG_ON(check_hotplug_memory_range(start, size));
 
@@ -2161,25 +2173,20 @@ static int __ref try_remove_memory(u64 start, u64 size)
         * the same granularity it was added - a single memory block.
         */
        if (mhp_memmap_on_memory()) {
-               nr_vmemmap_pages = walk_memory_blocks(start, size, NULL,
-                                                     get_nr_vmemmap_pages_cb);
-               if (nr_vmemmap_pages) {
+               ret = walk_memory_blocks(start, size, &mem, test_has_altmap_cb);
+               if (ret) {
                        if (size != memory_block_size_bytes()) {
                                pr_warn("Refuse to remove %#llx - %#llx,"
                                        "wrong granularity\n",
                                        start, start + size);
                                return -EINVAL;
                        }
-
+                       altmap = mem->altmap;
                        /*
-                        * Let remove_pmd_table->free_hugepage_table do the
-                        * right thing if we used vmem_altmap when hot-adding
-                        * the range.
+                        * Mark altmap NULL so that we can add a debug
+                        * check on memblock free.
                         */
-                       mhp_altmap.base_pfn = PHYS_PFN(start);
-                       mhp_altmap.free = nr_vmemmap_pages;
-                       mhp_altmap.alloc = nr_vmemmap_pages;
-                       altmap = &mhp_altmap;
+                       mem->altmap = NULL;
                }
        }
 
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