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authorGravatar Matt Whitlock <busybox@mattwhitlock.name>2014-03-22 19:21:01 -0400
committerGravatar Denys Vlasenko <vda.linux@googlemail.com>2014-03-23 18:36:23 +0100
commit0a53b203f9e7157136c8ab4e8753008a63a56660 (patch)
treec99d5a423ba2e598b9ac19aca39f90dc59cad088 /util-linux
parentb9bbd4ddf622bc365726af4f2424210762e74b32 (diff)
downloadbusybox-0a53b203f9e7157136c8ab4e8753008a63a56660.tar.gz
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add discard option -d to swapon
Signed-off-by: Matt Whitlock <busybox@mattwhitlock.name> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'util-linux')
-rw-r--r--util-linux/Config.src9
-rw-r--r--util-linux/swaponoff.c85
2 files changed, 85 insertions, 9 deletions
diff --git a/util-linux/Config.src b/util-linux/Config.src
index 5a8b0063b..c1cd6daa4 100644
--- a/util-linux/Config.src
+++ b/util-linux/Config.src
@@ -599,6 +599,15 @@ config SWAPONOFF
space. If you are not using any swap space, you can leave this
option disabled.
+config FEATURE_SWAPON_DISCARD
+ bool "Support discard option -d"
+ default y
+ depends on SWAPONOFF
+ help
+ Enable support for discarding swap area blocks at swapon and/or as
+ the kernel frees them. This option enables both the -d option on
+ 'swapon' and the 'discard' option for swap entries in /etc/fstab.
+
config FEATURE_SWAPON_PRI
bool "Support priority option -p"
default y
diff --git a/util-linux/swaponoff.c b/util-linux/swaponoff.c
index d5bfe1888..a7ad6db79 100644
--- a/util-linux/swaponoff.c
+++ b/util-linux/swaponoff.c
@@ -8,10 +8,14 @@
*/
//usage:#define swapon_trivial_usage
-//usage: "[-a]" IF_FEATURE_SWAPON_PRI(" [-p PRI]") " [DEVICE]"
+//usage: "[-a]" IF_FEATURE_SWAPON_DISCARD(" [-d[POL]]") IF_FEATURE_SWAPON_PRI(" [-p PRI]") " [DEVICE]"
//usage:#define swapon_full_usage "\n\n"
//usage: "Start swapping on DEVICE\n"
//usage: "\n -a Start swapping on all swap devices"
+//usage: IF_FEATURE_SWAPON_DISCARD(
+//usage: "\n -d[POL] Discard blocks at swapon (POL=once),"
+//usage: "\n as freed (POL=pages), or both (POL omitted)"
+//usage: )
//usage: IF_FEATURE_SWAPON_PRI(
//usage: "\n -p PRI Set swap device priority"
//usage: )
@@ -38,7 +42,22 @@
# define MNTTYPE_SWAP "swap"
#endif
-#if ENABLE_FEATURE_SWAPON_PRI
+#if ENABLE_FEATURE_SWAPON_DISCARD
+#ifndef SWAP_FLAG_DISCARD
+#define SWAP_FLAG_DISCARD 0x10000
+#endif
+#ifndef SWAP_FLAG_DISCARD_ONCE
+#define SWAP_FLAG_DISCARD_ONCE 0x20000
+#endif
+#ifndef SWAP_FLAG_DISCARD_PAGES
+#define SWAP_FLAG_DISCARD_PAGES 0x40000
+#endif
+#define SWAP_FLAG_DISCARD_MASK \
+ (SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | SWAP_FLAG_DISCARD_PAGES)
+#endif
+
+
+#if ENABLE_FEATURE_SWAPON_DISCARD || ENABLE_FEATURE_SWAPON_PRI
struct globals {
int flags;
} FIX_ALIASING;
@@ -98,9 +117,23 @@ static int do_em_all(void)
if (applet_name[5] != 'n'
|| hasmntopt(m, MNTOPT_NOAUTO) == NULL
) {
-#if ENABLE_FEATURE_SWAPON_PRI
+#if ENABLE_FEATURE_SWAPON_DISCARD || ENABLE_FEATURE_SWAPON_PRI
char *p;
g_flags = cl_flags; /* each swap space might have different flags */
+#if ENABLE_FEATURE_SWAPON_DISCARD
+ p = hasmntopt(m, "discard");
+ if (p) {
+ if (p[7] == '=') {
+ if (strncmp(p + 8, "once", 4) == 0 && (p[12] == ',' || p[12] == '\0'))
+ g_flags = (g_flags & ~SWAP_FLAG_DISCARD_MASK) | SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE;
+ else if (strncmp(p + 8, "pages", 5) == 0 && (p[13] == ',' || p[13] == '\0'))
+ g_flags = (g_flags & ~SWAP_FLAG_DISCARD_MASK) | SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_PAGES;
+ }
+ else if (p[7] == ',' || p[7] == '\0')
+ g_flags = (g_flags & ~SWAP_FLAG_DISCARD_MASK) | SWAP_FLAG_DISCARD;
+ }
+#endif
+#if ENABLE_FEATURE_SWAPON_PRI
p = hasmntopt(m, "pri");
if (p) {
/* Max allowed 32767 (== SWAP_FLAG_PRIO_MASK) */
@@ -112,6 +145,7 @@ static int do_em_all(void)
}
}
#endif
+#endif
err += swap_enable_disable(m->mnt_fsname);
}
}
@@ -127,24 +161,57 @@ int swap_on_off_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int swap_on_off_main(int argc UNUSED_PARAM, char **argv)
{
int ret;
+#if ENABLE_FEATURE_SWAPON_DISCARD
+ char *discard = NULL;
+#endif
#if ENABLE_FEATURE_SWAPON_PRI
unsigned prio;
#endif
INIT_G();
-#if !ENABLE_FEATURE_SWAPON_PRI
+#if !ENABLE_FEATURE_SWAPON_DISCARD && !ENABLE_FEATURE_SWAPON_PRI
ret = getopt32(argv, "a");
#else
+#if ENABLE_FEATURE_SWAPON_PRI
if (applet_name[5] == 'n')
opt_complementary = "p+";
- ret = getopt32(argv, (applet_name[5] == 'n') ? "ap:" : "a", &prio);
+#endif
+ ret = getopt32(argv, (applet_name[5] == 'n') ?
+#if ENABLE_FEATURE_SWAPON_DISCARD
+ "d::"
+#endif
+#if ENABLE_FEATURE_SWAPON_PRI
+ "p:"
+#endif
+ "a" : "a"
+#if ENABLE_FEATURE_SWAPON_DISCARD
+ , &discard
+#endif
+#if ENABLE_FEATURE_SWAPON_PRI
+ , &prio
+#endif
+ );
+#endif
- if (ret & 2) { // -p
- g_flags = SWAP_FLAG_PREFER |
- MIN(prio, SWAP_FLAG_PRIO_MASK);
- ret &= 1;
+#if ENABLE_FEATURE_SWAPON_DISCARD
+ if (ret & 1) { // -d
+ if (!discard)
+ g_flags |= SWAP_FLAG_DISCARD;
+ else if (strcmp(discard, "once") == 0)
+ g_flags |= SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE;
+ else if (strcmp(discard, "pages") == 0)
+ g_flags |= SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_PAGES;
+ else
+ bb_show_usage();
}
+ ret >>= 1;
+#endif
+#if ENABLE_FEATURE_SWAPON_PRI
+ if (ret & 1) // -p
+ g_flags |= SWAP_FLAG_PREFER |
+ MIN(prio, SWAP_FLAG_PRIO_MASK);
+ ret >>= 1;
#endif
if (ret /* & 1: not needed */) // -a