From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/mm/memory_hotplug.c | 111 ++++++++++++++++++++++++++++++++++++++++++++++---------
1 files changed, 92 insertions(+), 19 deletions(-)
diff --git a/kernel/mm/memory_hotplug.c b/kernel/mm/memory_hotplug.c
index 9176bae..386d85f 100644
--- a/kernel/mm/memory_hotplug.c
+++ b/kernel/mm/memory_hotplug.c
@@ -1334,7 +1334,7 @@
if (PageHuge(page)) {
pfn = page_to_pfn(head) + compound_nr(head) - 1;
- isolate_huge_page(head, &source);
+ isolate_hugetlb(head, &source);
continue;
} else if (PageTransHuge(page))
pfn = page_to_pfn(head) + thp_nr_pages(page) - 1;
@@ -1865,39 +1865,112 @@
}
EXPORT_SYMBOL_GPL(remove_memory_subsection);
+static int try_offline_memory_block(struct memory_block *mem, void *arg)
+{
+ uint8_t online_type = MMOP_ONLINE_KERNEL;
+ uint8_t **online_types = arg;
+ struct page *page;
+ int rc;
+
+ /*
+ * Sense the online_type via the zone of the memory block. Offlining
+ * with multiple zones within one memory block will be rejected
+ * by offlining code ... so we don't care about that.
+ */
+ page = pfn_to_online_page(section_nr_to_pfn(mem->start_section_nr));
+ if (page && zone_idx(page_zone(page)) == ZONE_MOVABLE)
+ online_type = MMOP_ONLINE_MOVABLE;
+
+ rc = device_offline(&mem->dev);
+ /*
+ * Default is MMOP_OFFLINE - change it only if offlining succeeded,
+ * so try_reonline_memory_block() can do the right thing.
+ */
+ if (!rc)
+ **online_types = online_type;
+
+ (*online_types)++;
+ /* Ignore if already offline. */
+ return rc < 0 ? rc : 0;
+}
+
+static int try_reonline_memory_block(struct memory_block *mem, void *arg)
+{
+ uint8_t **online_types = arg;
+ int rc;
+
+ if (**online_types != MMOP_OFFLINE) {
+ mem->online_type = **online_types;
+ rc = device_online(&mem->dev);
+ if (rc < 0)
+ pr_warn("%s: Failed to re-online memory: %d",
+ __func__, rc);
+ }
+
+ /* Continue processing all remaining memory blocks. */
+ (*online_types)++;
+ return 0;
+}
+
/*
- * Try to offline and remove a memory block. Might take a long time to
- * finish in case memory is still in use. Primarily useful for memory devices
- * that logically unplugged all memory (so it's no longer in use) and want to
- * offline + remove the memory block.
+ * Try to offline and remove memory. Might take a long time to finish in case
+ * memory is still in use. Primarily useful for memory devices that logically
+ * unplugged all memory (so it's no longer in use) and want to offline + remove
+ * that memory.
*/
int offline_and_remove_memory(int nid, u64 start, u64 size)
{
- struct memory_block *mem;
- int rc = -EINVAL;
+ const unsigned long mb_count = size / memory_block_size_bytes();
+ uint8_t *online_types, *tmp;
+ int rc;
if (!IS_ALIGNED(start, memory_block_size_bytes()) ||
- size != memory_block_size_bytes())
- return rc;
-
- lock_device_hotplug();
- mem = find_memory_block(__pfn_to_section(PFN_DOWN(start)));
- if (mem)
- rc = device_offline(&mem->dev);
- /* Ignore if the device is already offline. */
- if (rc > 0)
- rc = 0;
+ !IS_ALIGNED(size, memory_block_size_bytes()) || !size)
+ return -EINVAL;
/*
- * In case we succeeded to offline the memory block, remove it.
+ * We'll remember the old online type of each memory block, so we can
+ * try to revert whatever we did when offlining one memory block fails
+ * after offlining some others succeeded.
+ */
+ online_types = kmalloc_array(mb_count, sizeof(*online_types),
+ GFP_KERNEL);
+ if (!online_types)
+ return -ENOMEM;
+ /*
+ * Initialize all states to MMOP_OFFLINE, so when we abort processing in
+ * try_offline_memory_block(), we'll skip all unprocessed blocks in
+ * try_reonline_memory_block().
+ */
+ memset(online_types, MMOP_OFFLINE, mb_count);
+
+ lock_device_hotplug();
+
+ tmp = online_types;
+ rc = walk_memory_blocks(start, size, &tmp, try_offline_memory_block);
+
+ /*
+ * In case we succeeded to offline all memory, remove it.
* This cannot fail as it cannot get onlined in the meantime.
*/
if (!rc) {
rc = try_remove_memory(nid, start, size);
- WARN_ON_ONCE(rc);
+ if (rc)
+ pr_err("%s: Failed to remove memory: %d", __func__, rc);
+ }
+
+ /*
+ * Rollback what we did. While memory onlining might theoretically fail
+ * (nacked by a notifier), it barely ever happens.
+ */
+ if (rc) {
+ tmp = online_types;
+ walk_memory_blocks(start, size, &tmp,
+ try_reonline_memory_block);
}
unlock_device_hotplug();
+ kfree(online_types);
return rc;
}
EXPORT_SYMBOL_GPL(offline_and_remove_memory);
--
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