From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
Mem hot remove operation may find memory in the hot add region
and create gaps in ha region list if there is hot-add memory
at that point. The following hot add msg may contain memory range
in these gaps. Handle such request and change gap range after
adding memory.
Signed-off-by: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
---
drivers/hv/hv_balloon.c | 108 ++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 105 insertions(+), 3 deletions(-)
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index f76c9bd7fe2f..5aaae62955bf 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -907,10 +907,11 @@ static int pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt)
continue;
/*
- * If the current start pfn is not where the covered_end
- * is, create a gap and update covered_end_pfn.
+ * If the current start pfn is greater than covered_end_pfn,
+ * create a gap and update covered_end_pfn. Start pfn may
+ * locate at gap rangs which is created during mem hot remove.
*/
- if (has->covered_end_pfn != start_pfn) {
+ if (has->covered_end_pfn < start_pfn) {
gap = kzalloc(sizeof(struct hv_hotadd_gap), GFP_ATOMIC);
if (!gap) {
ret = -ENOMEM;
@@ -949,6 +950,91 @@ static int pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt)
return ret;
}
+static int handle_hot_add_in_gap(unsigned long start, unsigned long pg_cnt,
+ struct hv_hotadd_state *has)
+{
+ struct hv_hotadd_gap *gap, *new_gap, *tmp_gap;
+ unsigned long pfn_cnt = pg_cnt;
+ unsigned long start_pfn = start;
+ unsigned long end_pfn;
+ unsigned long pages;
+ unsigned long pgs_ol;
+ unsigned long block_pages = HA_CHUNK;
+ unsigned long pfn;
+ int nid;
+ int ret;
+
+ list_for_each_entry_safe(gap, tmp_gap, &has->gap_list, list) {
+
+ if ((start_pfn < gap->start_pfn)
+ || (start_pfn >= gap->end_pfn))
+ continue;
+
+ end_pfn = min(gap->end_pfn, start_pfn + pfn_cnt);
+ pgs_ol = end_pfn - start_pfn;
+
+ /*
+ * hv_bring_pgs_online() identifies whether pfn
+ * should be online or not via checking pfn is in
+ * hot add covered range or gap range(Detail see
+ * has_pfn_is_backed()). So adjust gap before bringing
+ * online or add memory.
+ */
+ if (gap->end_pfn - gap->start_pfn == pgs_ol) {
+ list_del(&gap->list);
+ kfree(gap);
+ } else if (gap->start_pfn < start && gap->end_pfn == end_pfn) {
+ gap->end_pfn = start_pfn;
+ } else if (gap->end_pfn > end_pfn
+ && gap->start_pfn == start_pfn) {
+ gap->start_pfn = end_pfn;
+ } else {
+ gap->end_pfn = start_pfn;
+
+ new_gap = kzalloc(sizeof(struct hv_hotadd_gap),
+ GFP_ATOMIC);
+ if (!new_gap) {
+ do_hot_add = false;
+ return -ENOMEM;
+ }
+
+ INIT_LIST_HEAD(&new_gap->list);
+ new_gap->start_pfn = end_pfn;
+ new_gap->end_pfn = gap->end_pfn;
+ list_add_tail(&gap->list, &has->gap_list);
+ }
+
+ /* Bring online or add memmory in gaps. */
+ for (pfn = start_pfn; pfn < end_pfn;
+ pfn = round_up(pfn + 1, block_pages)) {
+ pages = min(round_up(pfn + 1, block_pages),
+ end_pfn) - pfn;
+
+ if (online_section_nr(pfn_to_section_nr(pfn))) {
+ hv_bring_pgs_online(has, pfn, pages);
+ } else {
+ nid = memory_add_physaddr_to_nid(PFN_PHYS(pfn));
+ ret = add_memory(nid, PFN_PHYS(pfn),
+ round_up(pages, block_pages)
+ << PAGE_SHIFT);
+ if (ret) {
+ pr_err("Fail to add memory in gaps(error=%d).\n",
+ ret);
+ do_hot_add = false;
+ return ret;
+ }
+ }
+ }
+
+ start_pfn += pgs_ol;
+ pfn_cnt -= pgs_ol;
+ if (!pfn_cnt)
+ break;
+ }
+
+ return pg_cnt - pfn_cnt;
+}
+
static unsigned long handle_pg_range(unsigned long pg_start,
unsigned long pg_count)
{
@@ -975,6 +1061,22 @@ static unsigned long handle_pg_range(unsigned long pg_start,
old_covered_state = has->covered_end_pfn;
+ /*
+ * If start_pfn is less than cover_end_pfn, the hot-add memory
+ * area is in the gap range.
+ */
+ if (start_pfn < has->covered_end_pfn) {
+ pgs_ol = handle_hot_add_in_gap(start_pfn, pfn_cnt, has);
+
+ pfn_cnt -= pgs_ol;
+ if (!pfn_cnt) {
+ res = pgs_ol;
+ break;
+ }
+
+ start_pfn += pgs_ol;
+ }
+
if (start_pfn < has->ha_end_pfn) {
/*
* This is the case where we are backing pages
--
2.14.5
