[PATCH v7 7/7] mm/memory_hotplug: Enable runtime update of memmap_on_memory parameter
From: Aneesh Kumar K.V <hidden>
Date: 2023-08-01 04:47:46
Subsystem:
memory hot(un)plug, memory management, the rest · Maintainers:
David Hildenbrand, Oscar Salvador, Andrew Morton, Linus Torvalds
Allow updating memmap_on_memory mode after the kernel boot. Memory hotplug done after the mode update will use the new mmemap_on_memory value. Acked-by: David Hildenbrand <redacted> Signed-off-by: Aneesh Kumar K.V <redacted> --- mm/memory_hotplug.c | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 1ce8ad04a980..d282664f558e 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c@@ -89,7 +89,10 @@ static int set_memmap_mode(const char *val, const struct kernel_param *kp) else mode = MEMMAP_ON_MEMORY_DISABLE; } + /* Avoid changing memmap mode during hotplug. */ + get_online_mems(); *((int *)kp->arg) = mode; + put_online_mems(); if (mode == MEMMAP_ON_MEMORY_FORCE) { unsigned long memmap_pages = memory_block_memmap_on_memory_pages();
@@ -110,7 +113,7 @@ static const struct kernel_param_ops memmap_mode_ops = { .set = set_memmap_mode, .get = get_memmap_mode, }; -module_param_cb(memmap_on_memory, &memmap_mode_ops, &memmap_mode, 0444); +module_param_cb(memmap_on_memory, &memmap_mode_ops, &memmap_mode, 0644); MODULE_PARM_DESC(memmap_on_memory, "Enable memmap on memory for memory hotplug\n" "With value \"force\" it could result in memory wastage due " "to memmap size limitations (Y/N/force)");
@@ -2172,22 +2175,20 @@ 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. */ - if (mhp_memmap_on_memory()) { - 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; - /* - * Mark altmap NULL so that we can add a debug - * check on memblock free. - */ - mem->altmap = NULL; + 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; + /* + * Mark altmap NULL so that we can add a debug + * check on memblock free. + */ + mem->altmap = NULL; } /* remove memmap entry */
--
2.41.0