On 06.07.23 10:50, 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.
Can you elaborate why ppc64 needs that and x86-64 + aarch64 don't?
IOW, why can't ppc64 simply allocate the vmemmap from the start of the
memblock (-> base_pfn) and use the stored number of vmemmap pages to
calculate the end_pfn?
To rephrase: if the vmemmap is not at the beginning and doesn't cover
full apgeblocks, memory onlining/offlining would be broken.
[...]
+/**
+ * struct vmem_altmap - pre-allocated storage for vmemmap_populate
+ * @base_pfn: base of the entire dev_pagemap mapping
+ * @reserve: pages mapped, but reserved for driver use (relative to @base)
+ * @free: free pages set aside in the mapping for memmap storage
+ * @align: pages reserved to meet allocation alignments
+ * @alloc: track pages consumed, private to vmemmap_populate()
+ */
+struct vmem_altmap {
+ unsigned long base_pfn;
+ const unsigned long end_pfn;
+ const unsigned long reserve;
+ unsigned long free;
+ unsigned long align;
+ unsigned long alloc;
+};
Instead of embedding that, what about conditionally allocating it and
store a pointer to it in the "struct memory_block"?
In the general case as of today, we don't have an altmap.
+
struct memory_block {
unsigned long start_section_nr;
unsigned long state; /* serialized by the dev->lock */
@@ -77,11 +94,7 @@ struct memory_block {
*/
struct zone *zone;
struct device dev;
- /*
- * Number of vmemmap pages. These pages
- * lay at the beginning of the memory block.
- */
- unsigned long nr_vmemmap_pages;
+ struct vmem_altmap altmap;
struct memory_group *group; /* group (if any) for this block */
struct list_head group_next; /* next block inside memory group */
#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_MEMORY_HOTPLUG)
@@ -147,7 +160,7 @@ static inline int hotplug_memory_notifier(notifier_fn_t fn, int pri)
extern int register_memory_notifier(struct notifier_block *nb);
extern void unregister_memory_notifier(struct notifier_block *nb);
int create_memory_block_devices(unsigned long start, unsigned long size,
[...]
static int check_cpu_on_node(int nid)
@@ -2036,9 +2042,8 @@ EXPORT_SYMBOL(try_offline_node);
static int __ref try_remove_memory(u64 start, u64 size)
{
- struct vmem_altmap mhp_altmap = {};
+ int ret;
struct vmem_altmap *altmap = NULL;
- unsigned long nr_vmemmap_pages;
int rc = 0, nid = NUMA_NO_NODE;
BUG_ON(check_hotplug_memory_range(start, size));
@@ -2060,24 +2065,16 @@ static int __ref try_remove_memory(u64 start, u64 size)
* We only support removing memory added with MHP_MEMMAP_ON_MEMORY in
* the same granularity it was added - a single memory block.
*/
+
^ unrealted change?
--
Cheers,
David / dhildenb
