Process MEM_OFFLINE and MEM_CANCEL_OFFLINE memory events to intercept any
possible error conditions during memory offline operation. This includes if
boot memory still got offlined even after an expilicit notifier failure or
if non-boot memory got declined for an offline request. This help improve
memory notifier robustness while also enhancing debug capabilities during
various potential memory offlining error conditions.
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Steve Capper <steve.capper@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
arch/arm64/mm/mmu.c | 52 ++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 47 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index a374e4f51a62..48c71d8a29b2 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1422,13 +1422,55 @@ static int prevent_bootmem_remove_notifier(struct notifier_block *nb,
unsigned long end_pfn = arg->start_pfn + arg->nr_pages;
unsigned long pfn = arg->start_pfn;
- if (action != MEM_GOING_OFFLINE)
+ if ((action != MEM_GOING_OFFLINE) && (action != MEM_OFFLINE) &&
+ (action != MEM_CANCEL_OFFLINE))
return NOTIFY_OK;
- for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
- ms = __pfn_to_section(pfn);
- if (early_section(ms))
- return NOTIFY_BAD;
+ if (action == MEM_GOING_OFFLINE) {
+ for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+ ms = __pfn_to_section(pfn);
+ if (early_section(ms)) {
+ pr_warn("Boot memory offlining attempted\n");
+ return NOTIFY_BAD;
+ }
+ }
+ } else if (action == MEM_OFFLINE) {
+ for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+ ms = __pfn_to_section(pfn);
+ if (early_section(ms)) {
+
+ /*
+ * This should have never happened. Boot memory
+ * offlining should have been prevented by this
+ * very notifier. Probably some memory removal
+ * procedure might have changed which would then
+ * require further debug.
+ */
+ pr_err("Boot memory offlined\n");
+ return NOTIFY_BAD;
+ }
+ }
+ } else if (action == MEM_CANCEL_OFFLINE) {
+ enum offline_failure_reason reason = *(int *)arg->data;
+
+ if (reason != OFFLINE_FAILURE_NOTIFIER)
+ return NOTIFY_OK;
+
+ for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+ ms = __pfn_to_section(pfn);
+ if (early_section(ms))
+ return NOTIFY_OK;
+ }
+
+ /*
+ * This should have never happened. Non boot memory
+ * offlining should never have been prevented from
+ * this notifier. Probably some memory hot removal
+ * procedure might have changed which would then
+ * require further debug.
+ */
+ pr_err("Notifier declined non boot memory offlining\n");
+ return NOTIFY_BAD;
}
return NOTIFY_OK;
}
--
2.20.1
