fs_mgr: allow for zramsize to be specified as percentage of total memory
If the zramsize entry has a % size at the end, as in the following example:
/dev/block/zram0 none swap defaults zramsize=25%
then we will set the value as that percentage of total RAM, as read by scanning
/proc/meminfo.
b/20760266 Seed common build allocated too much for zRAM-backed swap
Change-Id: I17c91d311ba99ae7adae112bfe1b38542ea69b80
Signed-off-by: Iliyan Malchev <malchev@google.com>
diff --git a/fs_mgr/fs_mgr_fstab.c b/fs_mgr/fs_mgr_fstab.c
index ab8f128..c200b05 100644
--- a/fs_mgr/fs_mgr_fstab.c
+++ b/fs_mgr/fs_mgr_fstab.c
@@ -15,10 +15,12 @@
*/
#include <ctype.h>
+#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mount.h>
+#include <unistd.h>
#include "fs_mgr_priv.h"
@@ -72,6 +74,19 @@
{ 0, 0 },
};
+static uint64_t calculate_zram_size(unsigned int percentage)
+{
+ uint64_t total;
+
+ total = sysconf(_SC_PHYS_PAGES);
+ total *= percentage;
+ total /= 100;
+
+ total *= sysconf(_SC_PAGESIZE);
+
+ return total;
+}
+
static int parse_flags(char *flags, struct flag_list *fl,
struct fs_mgr_flag_values *flag_vals,
char *fs_options, int fs_options_len)
@@ -145,7 +160,12 @@
} else if ((fl[i].flag == MF_SWAPPRIO) && flag_vals) {
flag_vals->swap_prio = strtoll(strchr(p, '=') + 1, NULL, 0);
} else if ((fl[i].flag == MF_ZRAMSIZE) && flag_vals) {
- flag_vals->zram_size = strtoll(strchr(p, '=') + 1, NULL, 0);
+ int is_percent = !!strrchr(p, '%');
+ unsigned int val = strtoll(strchr(p, '=') + 1, NULL, 0);
+ if (is_percent)
+ flag_vals->zram_size = calculate_zram_size(val);
+ else
+ flag_vals->zram_size = val;
}
break;
}