lsmem/chmem: add memory zone awareness

With this patch, valid memory zones can be shown with lsmem, and chmem can
set memory online/offline in a specific memory zone, if allowed by the
kernel. The valid memory zones are read from the "valid_zones" sysfs
attribute, and setting memory online to a specific zone is done by
echoing "online_kernel" or "online_movable" to the "state" sysfs
attribute, in addition to the previous "online".

This patch also changes the default behavior of chmem, when setting memory
online without specifying a memory zone. If valid, memory will be set
online to the zone Movable. This zone is preferable for memory hotplug, as
it makes memory offline much more likely to succeed.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>

1 files changed, 97 insertions, 1 deletions

diff --git a/sys-utils/lsmem.c b/sys-utils/lsmem.c
index aeffd29dd..1d26579fd 100644
--- a/sys-utils/lsmem.c
+++ b/sys-utils/lsmem.c
@@ -42,11 +42,25 @@
 #define MEMORY_STATE_GOING_OFFLINE	2
 #define MEMORY_STATE_UNKNOWN		3
 
+enum zone_id {
+	ZONE_DMA = 0,
+	ZONE_DMA32,
+	ZONE_NORMAL,
+	ZONE_HIGHMEM,
+	ZONE_MOVABLE,
+	ZONE_DEVICE,
+	ZONE_NONE,
+	ZONE_UNKNOWN,
+	MAX_NR_ZONES,
+};
+
 struct memory_block {
 	uint64_t	index;
 	uint64_t	count;
 	int		state;
 	int		node;
+	int		nr_zones;
+	int		zones[MAX_NR_ZONES];
 	unsigned int	removable:1;
 };
 
@@ -72,7 +86,9 @@ struct lsmem {
 				want_state : 1,
 				want_removable : 1,
 				want_summary : 1,
-				want_table : 1;
+				want_table : 1,
+				want_zones : 1,
+				have_zones : 1;
 };
 
 enum {
@@ -82,6 +98,18 @@ enum {
 	COL_REMOVABLE,
 	COL_BLOCK,
 	COL_NODE,
+	COL_ZONES,
+};
+
+static char *zone_names[] = {
+	[ZONE_DMA]	= "DMA",
+	[ZONE_DMA32]	= "DMA32",
+	[ZONE_NORMAL]	= "Normal",
+	[ZONE_HIGHMEM]	= "Highmem",
+	[ZONE_MOVABLE]	= "Movable",
+	[ZONE_DEVICE]	= "Device",
+	[ZONE_NONE]	= "None",	/* block contains more than one zone, can't be offlined */
+	[ZONE_UNKNOWN]	= "Unknown",
 };
 
 /* column names */
@@ -102,6 +130,7 @@ static struct coldesc coldescs[] = {
 	[COL_REMOVABLE]	= { "REMOVABLE", 0, SCOLS_FL_RIGHT, N_("memory is removable")},
 	[COL_BLOCK]	= { "BLOCK", 0, SCOLS_FL_RIGHT, N_("memory block number or blocks range")},
 	[COL_NODE]	= { "NODE", 0, SCOLS_FL_RIGHT, N_("numa node of memory")},
+	[COL_ZONES]	= { "ZONES", 0, SCOLS_FL_RIGHT, N_("valid zones for the memory range")},
 };
 
 /* columns[] array specifies all currently wanted output column. The columns
@@ -120,6 +149,20 @@ static inline size_t err_columns_index(size_t arysz, size_t idx)
 	return idx;
 }
 
+/*
+ * name must be null-terminated
+ */
+static int zone_name_to_id(const char *name)
+{
+	size_t i;
+
+	for (i = 0; i < ARRAY_SIZE(zone_names); i++) {
+		if (!strcasecmp(name, zone_names[i]))
+			return i;
+	}
+	return ZONE_UNKNOWN;
+}
+
 #define add_column(ary, n, id)	\
 		((ary)[ err_columns_index(ARRAY_SIZE(ary), (n)) ] = (id))
 
@@ -214,6 +257,25 @@ static void add_scols_line(struct lsmem *lsmem, struct memory_block *blk)
 			else
 				str = xstrdup("-");
 			break;
+		case COL_ZONES:
+			if (lsmem->have_zones) {
+				char valid_zones[BUFSIZ];
+				int j, zone_id;
+
+				valid_zones[0] = '\0';
+				for (j = 0; j < blk->nr_zones; j++) {
+					zone_id = blk->zones[j];
+					if (strlen(valid_zones) +
+					    strlen(zone_names[zone_id]) > BUFSIZ - 2)
+						break;
+					strcat(valid_zones, zone_names[zone_id]);
+					if (j + 1 < blk->nr_zones)
+						strcat(valid_zones, "/");
+				}
+				str = xstrdup(valid_zones);
+			} else
+				str = xstrdup("-");
+			break;
 		}
 
 		if (str && scols_line_refer_data(line, i, str) != 0)
@@ -272,7 +334,9 @@ static int memory_block_get_node(char *name)
 static void memory_block_read_attrs(struct lsmem *lsmem, char *name,
 				    struct memory_block *blk)
 {
+	char *token = NULL;
 	char line[BUFSIZ];
+	int i;
 
 	blk->count = 1;
 	blk->index = strtoumax(name + 6, NULL, 10); /* get <num> of "memory<num>" */
@@ -287,11 +351,26 @@ static void memory_block_read_attrs(struct lsmem *lsmem, char *name,
 		blk->state = MEMORY_STATE_GOING_OFFLINE;
 	if (lsmem->have_nodes)
 		blk->node = memory_block_get_node(name);
+
+	blk->nr_zones = 0;
+	if (lsmem->have_zones) {
+		path_read_str(line, sizeof(line), _PATH_SYS_MEMORY"/%s/%s", name,
+			      "valid_zones");
+		token = strtok(line, " ");
+	}
+	for (i = 0; i < MAX_NR_ZONES; i++) {
+		if (token) {
+			blk->zones[i] = zone_name_to_id(token);
+			blk->nr_zones++;
+			token = strtok(NULL, " ");
+		}
+	}
 }
 
 static int is_mergeable(struct lsmem *lsmem, struct memory_block *blk)
 {
 	struct memory_block *curr;
+	int i;
 
 	if (!lsmem->nblocks)
 		return 0;
@@ -308,6 +387,15 @@ static int is_mergeable(struct lsmem *lsmem, struct memory_block *blk)
 		if (curr->node != blk->node)
 			return 0;
 	}
+	if (lsmem->want_zones && lsmem->have_zones) {
+		if (curr->nr_zones != blk->nr_zones)
+			return 0;
+		for (i = 0; i < curr->nr_zones; i++) {
+			if (curr->zones[i] == ZONE_UNKNOWN ||
+			    curr->zones[i] != blk->zones[i])
+				return 0;
+		}
+	}
 	return 1;
 }
 
@@ -362,6 +450,12 @@ static void read_basic_info(struct lsmem *lsmem)
 
 	if (memory_block_get_node(lsmem->dirs[0]->d_name) != -1)
 		lsmem->have_nodes = 1;
+
+	/* The valid_zones sysfs attribute was introduced with kernel 3.18 */
+	if (path_exist(_PATH_SYS_MEMORY "/memory0/valid_zones"))
+		lsmem->have_zones = 1;
+	else if (lsmem->want_zones)
+		warnx(_("Cannot read zones, no valid_zones sysfs attribute present"));
 }
 
 static void __attribute__((__noreturn__)) usage(void)
@@ -553,6 +647,8 @@ int main(int argc, char **argv)
 		lsmem->want_node = 1;
 	if (has_column(COL_REMOVABLE))
 		lsmem->want_removable = 1;
+	if (has_column(COL_ZONES))
+		lsmem->want_zones = 1;
 
 	/*
 	 * Read data and print output