This patch adds the --add-ramdisk-swap option, which when specified,
creates and activiates swap space on ramdisk for the duration of
the positive pool resize. If the ramdisk size on the system is not
as big as the huge page size, then swap is initialized on multiple
ramdisks.
Signed-off-by: Avantika Mathur <mat...@us.ibm.com>
---
Index: libhugetlbfs/hugeadm.c
===================================================================
--- libhugetlbfs.orig/hugeadm.c 2009-06-29 01:52:26.000000000 -0700
+++ libhugetlbfs/hugeadm.c 2009-06-29 02:10:53.000000000 -0700
@@ -32,6 +32,7 @@
#include <unistd.h>
#include <grp.h>
#include <pwd.h>
+#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
@@ -90,6 +91,8 @@
OPTION("--add-temp-swap[=count]", "Specified with --pool-pages-min to create");
CONT("temporary swap space for the duration of the pool resize. Default swap");
CONT("size is 5 huge pages. Optional arg sets size to 'count' huge pages");
+ OPTION("--add-ramdisk-swap", "Specified with --pool-pages-min to create");
+ CONT("swap space on ramdisks. By default, swap is removed after the resize.");
OPTION("--enable-zone-movable", "Use ZONE_MOVABLE for huge pages");
OPTION("--disable-zone-movable", "Do not use ZONE_MOVABLE for huge pages");
OPTION("--create-mounts", "Creates a mount point for each available");
@@ -125,6 +128,7 @@
int opt_hard = 0;
int opt_movable = -1;
int opt_temp_swap = 0;
+int opt_ramdisk_swap = 0;
int verbose_level = VERBOSITY_DEFAULT;
void setup_environment(char *var, char *val)
@@ -205,7 +209,9 @@
#define LONG_MOVABLE_DISABLE (LONG_MOVABLE|'d')
#define LONG_HARD ('h' << 8)
-#define LONG_ADD_TEMP_SWAP ('s' << 8)
+#define LONG_SWAP ('s' << 8)
+#define LONG_SWAP_DISK (LONG_SWAP|'d')
+#define LONG_SWAP_RAMDISK (LONG_SWAP|'r')
#define LONG_PAGE ('P' << 8)
#define LONG_PAGE_SIZES (LONG_PAGE|'s')
@@ -675,6 +681,81 @@
DEBUG("swapoff %s\n", file);
}
+char* add_ramdisk_swap(long page_size) {
+ char ramdisk[PATH_MAX];
+ char mkswap_cmd[PATH_MAX];
+ char disk_list[PATH_MAX] = "";
+ char *ret_list;
+ int disk_num=0;
+ int count = 0;
+ long ramdisk_size;
+ int ret;
+ int fd;
+
+ snprintf(ramdisk, PATH_MAX, "/dev/ram%i", disk_num);
+ ret_list = ramdisk;
+ fd = open(ramdisk, O_RDONLY);
+ ioctl(fd, BLKGETSIZE, &ramdisk_size);
+ close(fd);
+
+ ramdisk_size = ramdisk_size * 512;
+ count = (page_size/ramdisk_size) + 1;
+ opt_ramdisk_swap = count;
+
+ if (count > 1) {
+ INFO("Swap will be initialized on multiple ramdisks because\n\
+ ramdisk size is less than huge page size. To avoid\n\
+ this in the future, use kernel command line parameter\n\
+ ramdisk_size=N, to set ramdisk size to N blocks.\n");
+ }
+
+ while (count > 0) {
+ snprintf(ramdisk, PATH_MAX, "/dev/ram%i", disk_num);
+ if (access(ramdisk, F_OK) != 0){
+ break;
+ }
+ disk_num++;
+ snprintf(mkswap_cmd, PATH_MAX, "mkswap %s", ramdisk);
+ ret = system(mkswap_cmd);
+ if (WIFSIGNALED(ret)) {
+ WARNING("Call to mkswap failed\n");
+ continue;
+ } else if (WIFEXITED(ret)) {
+ ret = WEXITSTATUS(ret);
+ if (ret) {
+ WARNING("Call to mkswap failed\n");
+ continue;
+ }
+ }
+ DEBUG("swapon %s\n", ramdisk);
+ if (swapon(ramdisk, 0)) {
+ WARNING("swapon on %s failed: %s\n", ramdisk, strerror(errno));
+ opt_temp_swap = 0;
+ continue;
+ }
+ count--;
+ strcat(disk_list, " ");
+ strcat(disk_list, ramdisk);
+ }
+ ret_list = disk_list;
+ return ret_list;
+}
+
+void rem_ramdisk_swap(char* ramdisk_list){
+ char *ramdisk;
+ char *iter = NULL;
+
+ ramdisk = strtok_r(ramdisk_list, " ", &iter);
+ while (ramdisk != NULL) {
+ DEBUG("swapoff %s\n", ramdisk);
+ if (swapoff(ramdisk)) {
+ WARNING("swapoff on %s failed: %s\n", ramdisk, strerror(errno));
+ continue;
+ }
+ ramdisk = strtok_r(NULL, " ", &iter);
+ }
+}
+
enum {
POOL_MIN,
POOL_MAX,
@@ -718,6 +799,7 @@
char *iter = NULL;
char *page_size_str = NULL;
char *adjust_str = NULL;
+ char *disk_list = NULL;
long page_size;
unsigned long min;
@@ -786,9 +868,12 @@
if (min > min_orig) {
if (opt_temp_swap)
add_temp_swap(page_size);
+ if (opt_ramdisk_swap)
+ disk_list = add_ramdisk_swap(page_size);
check_swap();
}
+
INFO("setting HUGEPAGES_TOTAL to %ld\n", min);
set_huge_page_counter(page_size, HUGEPAGES_TOTAL, min);
get_pool_size(page_size, &pools[pos]);
@@ -810,8 +895,12 @@
get_pool_size(page_size, &pools[pos]);
}
- if ((min > min_orig) && opt_temp_swap)
- rem_temp_swap();
+ if (min > min_orig) {
+ if (opt_temp_swap)
+ rem_temp_swap();
+ else if (opt_ramdisk_swap)
+ rem_ramdisk_swap(disk_list);
+ }
/*
* HUGEPAGES_TOTAL is not guarenteed to check to exactly the figure
@@ -885,7 +974,8 @@
{"enable-zone-movable", no_argument, NULL, LONG_MOVABLE_ENABLE},
{"disable-zone-movable", no_argument, NULL, LONG_MOVABLE_DISABLE},
{"hard", no_argument, NULL, LONG_HARD},
- {"add-temp-swap", optional_argument, NULL, LONG_ADD_TEMP_SWAP},
+ {"add-temp-swap", optional_argument, NULL, LONG_SWAP_DISK},
+ {"add-ramdisk-swap", no_argument, NULL, LONG_SWAP_RAMDISK},
{"create-mounts", no_argument, NULL, LONG_CREATE_MOUNTS},
{"create-user-mounts", required_argument, NULL, LONG_CREATE_USER_MOUNTS},
{"create-group-mounts", required_argument, NULL, LONG_CREATE_GROUP_MOUNTS},
@@ -941,13 +1031,17 @@
opt_hard = 1;
continue;
- case LONG_ADD_TEMP_SWAP:
+ case LONG_SWAP_DISK:
if (optarg)
opt_temp_swap = atoi(optarg);
else
opt_temp_swap = -1;
break;
+ case LONG_SWAP_RAMDISK:
+ opt_ramdisk_swap = 1;
+ break;
+
case LONG_LIST_ALL_MOUNTS:
opt_list_mounts = 1;
break;
Index: libhugetlbfs/man/hugeadm.8
===================================================================
--- libhugetlbfs.orig/man/hugeadm.8 2009-06-29 01:52:26.000000000 -0700
+++ libhugetlbfs/man/hugeadm.8 2009-06-29 02:11:29.000000000 -0700
@@ -159,6 +159,18 @@
The default swap size is 5 huge pages, the optional argument <count> sets
the swap size to <count> huge pages.
+.TP
+.B --add-ramdisk-swap
+
+This option is specified with --pool-pages-min to initialize swap in memory
+on ram disks. When increasing the size of the pool, it can be necessary to
+reclaim pages so that contiguous memory is freed and this often requires swap
+to be successful. If there isn't enough free disk space, swap can be
+initialized in RAM using this option. If the size of one ramdisk is not
+greater than the huge page size, then swap is initialized on multiple ramdisks.
+Swap is only created for a positive resize, and by default is removed once
+the resize operation is completed.
+
.PP
The following options affect the verbosity of libhugetlbfs.
------------------------------------------------------------------------------
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