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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 space. If you are not using any swap space, you can leave this
option disabled. 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 config FEATURE_SWAPON_PRI
bool "Support priority option -p" bool "Support priority option -p"
default y default y

85
util-linux/swaponoff.c
View File

@ -8,10 +8,14 @@
*/ */
//usage:#define swapon_trivial_usage //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:#define swapon_full_usage "\n\n"
//usage: "Start swapping on DEVICE\n" //usage: "Start swapping on DEVICE\n"
//usage: "\n -a Start swapping on all swap devices" //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: IF_FEATURE_SWAPON_PRI(
//usage: "\n -p PRI Set swap device priority" //usage: "\n -p PRI Set swap device priority"
//usage: ) //usage: )
@ -38,7 +42,22 @@
# define MNTTYPE_SWAP "swap" # define MNTTYPE_SWAP "swap"
#endif #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 { struct globals {
int flags; int flags;
} FIX_ALIASING; } FIX_ALIASING;
@ -98,9 +117,23 @@ static int do_em_all(void)
if (applet_name[5] != 'n' if (applet_name[5] != 'n'
|| hasmntopt(m, MNTOPT_NOAUTO) == NULL || hasmntopt(m, MNTOPT_NOAUTO) == NULL
) { ) {
#if ENABLE_FEATURE_SWAPON_PRI #if ENABLE_FEATURE_SWAPON_DISCARD || ENABLE_FEATURE_SWAPON_PRI
char *p; char *p;
g_flags = cl_flags; /* each swap space might have different flags */ 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"); p = hasmntopt(m, "pri");
if (p) { if (p) {
/* Max allowed 32767 (== SWAP_FLAG_PRIO_MASK) */ /* Max allowed 32767 (== SWAP_FLAG_PRIO_MASK) */
@ -111,6 +144,7 @@ static int do_em_all(void)
MIN(prio, SWAP_FLAG_PRIO_MASK); MIN(prio, SWAP_FLAG_PRIO_MASK);
} }
} }
#endif
#endif #endif
err += swap_enable_disable(m->mnt_fsname); 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 swap_on_off_main(int argc UNUSED_PARAM, char **argv)
{ {
int ret; int ret;
#if ENABLE_FEATURE_SWAPON_DISCARD
char *discard = NULL;
#endif
#if ENABLE_FEATURE_SWAPON_PRI #if ENABLE_FEATURE_SWAPON_PRI
unsigned prio; unsigned prio;
#endif #endif
INIT_G(); INIT_G();
#if !ENABLE_FEATURE_SWAPON_PRI #if !ENABLE_FEATURE_SWAPON_DISCARD && !ENABLE_FEATURE_SWAPON_PRI
ret = getopt32(argv, "a"); ret = getopt32(argv, "a");
#else #else
#if ENABLE_FEATURE_SWAPON_PRI
if (applet_name[5] == 'n') if (applet_name[5] == 'n')
opt_complementary = "p+"; 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 #if ENABLE_FEATURE_SWAPON_DISCARD
g_flags = SWAP_FLAG_PREFER | if (ret & 1) { // -d
MIN(prio, SWAP_FLAG_PRIO_MASK); if (!discard)
ret &= 1; 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 #endif
if (ret /* & 1: not needed */) // -a if (ret /* & 1: not needed */) // -a