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add discard option -d to swapon

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Signed-off-by: Matt Whitlock <busybox@mattwhitlock.name>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Matt Whitlock 2014-03-22 19:21:01 -04:00 committed by Denys Vlasenko
parent b9bbd4ddf6
commit 0a53b203f9
2 changed files with 85 additions and 9 deletions
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9
util-linux/Config.src
View File

@ -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

85
util-linux/swaponoff.c
View File

@ -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) */
@ -111,6 +144,7 @@ static int do_em_all(void)
MIN(prio, SWAP_FLAG_PRIO_MASK);
}
}
#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