diff options
author | Andreas Mohr <andi@rhlx01.fht-esslingen.de> | 2006-06-23 05:04:17 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-06-23 10:42:56 -0400 |
commit | 87af2ffd4ccd0e6a2ff316fd008a9bedb4a4cb66 (patch) | |
tree | 4cd80cf123aa220e5c1c3c534bf09fa8d001ad28 /arch | |
parent | a0b4da91f4c5710b9c20219a19e905145647b48b (diff) |
[PATCH] i386 apm.c optimization
- avoid expensive modulo (integer division) which happened
since APM_MAX_EVENTS is 20 (non-power-of-2)
- kill compiler warnings by initializing two variables
- add __read_mostly to some important static variables that are read often
(by idle loop etc.)
- constify several structures
Signed-off-by: Andreas Mohr <andi@lisas.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/i386/kernel/apm.c | 39 |
1 files changed, 22 insertions, 17 deletions
diff --git a/arch/i386/kernel/apm.c b/arch/i386/kernel/apm.c index df0e1745f189..9e819eb68229 100644 --- a/arch/i386/kernel/apm.c +++ b/arch/i386/kernel/apm.c | |||
@@ -374,14 +374,14 @@ static struct { | |||
374 | unsigned short segment; | 374 | unsigned short segment; |
375 | } apm_bios_entry; | 375 | } apm_bios_entry; |
376 | static int clock_slowed; | 376 | static int clock_slowed; |
377 | static int idle_threshold = DEFAULT_IDLE_THRESHOLD; | 377 | static int idle_threshold __read_mostly = DEFAULT_IDLE_THRESHOLD; |
378 | static int idle_period = DEFAULT_IDLE_PERIOD; | 378 | static int idle_period __read_mostly = DEFAULT_IDLE_PERIOD; |
379 | static int set_pm_idle; | 379 | static int set_pm_idle; |
380 | static int suspends_pending; | 380 | static int suspends_pending; |
381 | static int standbys_pending; | 381 | static int standbys_pending; |
382 | static int ignore_sys_suspend; | 382 | static int ignore_sys_suspend; |
383 | static int ignore_normal_resume; | 383 | static int ignore_normal_resume; |
384 | static int bounce_interval = DEFAULT_BOUNCE_INTERVAL; | 384 | static int bounce_interval __read_mostly = DEFAULT_BOUNCE_INTERVAL; |
385 | 385 | ||
386 | #ifdef CONFIG_APM_RTC_IS_GMT | 386 | #ifdef CONFIG_APM_RTC_IS_GMT |
387 | # define clock_cmos_diff 0 | 387 | # define clock_cmos_diff 0 |
@@ -390,8 +390,8 @@ static int bounce_interval = DEFAULT_BOUNCE_INTERVAL; | |||
390 | static long clock_cmos_diff; | 390 | static long clock_cmos_diff; |
391 | static int got_clock_diff; | 391 | static int got_clock_diff; |
392 | #endif | 392 | #endif |
393 | static int debug; | 393 | static int debug __read_mostly; |
394 | static int smp; | 394 | static int smp __read_mostly; |
395 | static int apm_disabled = -1; | 395 | static int apm_disabled = -1; |
396 | #ifdef CONFIG_SMP | 396 | #ifdef CONFIG_SMP |
397 | static int power_off; | 397 | static int power_off; |
@@ -403,8 +403,8 @@ static int realmode_power_off = 1; | |||
403 | #else | 403 | #else |
404 | static int realmode_power_off; | 404 | static int realmode_power_off; |
405 | #endif | 405 | #endif |
406 | static int exit_kapmd; | 406 | static int exit_kapmd __read_mostly; |
407 | static int kapmd_running; | 407 | static int kapmd_running __read_mostly; |
408 | #ifdef CONFIG_APM_ALLOW_INTS | 408 | #ifdef CONFIG_APM_ALLOW_INTS |
409 | static int allow_ints = 1; | 409 | static int allow_ints = 1; |
410 | #else | 410 | #else |
@@ -416,15 +416,15 @@ static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue); | |||
416 | static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue); | 416 | static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue); |
417 | static struct apm_user * user_list; | 417 | static struct apm_user * user_list; |
418 | static DEFINE_SPINLOCK(user_list_lock); | 418 | static DEFINE_SPINLOCK(user_list_lock); |
419 | static struct desc_struct bad_bios_desc = { 0, 0x00409200 }; | 419 | static const struct desc_struct bad_bios_desc = { 0, 0x00409200 }; |
420 | 420 | ||
421 | static char driver_version[] = "1.16ac"; /* no spaces */ | 421 | static const char driver_version[] = "1.16ac"; /* no spaces */ |
422 | 422 | ||
423 | /* | 423 | /* |
424 | * APM event names taken from the APM 1.2 specification. These are | 424 | * APM event names taken from the APM 1.2 specification. These are |
425 | * the message codes that the BIOS uses to tell us about events | 425 | * the message codes that the BIOS uses to tell us about events |
426 | */ | 426 | */ |
427 | static char * apm_event_name[] = { | 427 | static const char * const apm_event_name[] = { |
428 | "system standby", | 428 | "system standby", |
429 | "system suspend", | 429 | "system suspend", |
430 | "normal resume", | 430 | "normal resume", |
@@ -616,7 +616,7 @@ static u8 apm_bios_call(u32 func, u32 ebx_in, u32 ecx_in, | |||
616 | * @ecx_in: ECX register value for BIOS call | 616 | * @ecx_in: ECX register value for BIOS call |
617 | * @eax: EAX register on return from the BIOS call | 617 | * @eax: EAX register on return from the BIOS call |
618 | * | 618 | * |
619 | * Make a BIOS call that does only returns one value, or just status. | 619 | * Make a BIOS call that returns one value only, or just status. |
620 | * If there is an error, then the error code is returned in AH | 620 | * If there is an error, then the error code is returned in AH |
621 | * (bits 8-15 of eax) and this function returns non-zero. This is | 621 | * (bits 8-15 of eax) and this function returns non-zero. This is |
622 | * used for simpler BIOS operations. This call may hold interrupts | 622 | * used for simpler BIOS operations. This call may hold interrupts |
@@ -822,7 +822,7 @@ static void apm_do_busy(void) | |||
822 | #define IDLE_CALC_LIMIT (HZ * 100) | 822 | #define IDLE_CALC_LIMIT (HZ * 100) |
823 | #define IDLE_LEAKY_MAX 16 | 823 | #define IDLE_LEAKY_MAX 16 |
824 | 824 | ||
825 | static void (*original_pm_idle)(void); | 825 | static void (*original_pm_idle)(void) __read_mostly; |
826 | 826 | ||
827 | /** | 827 | /** |
828 | * apm_cpu_idle - cpu idling for APM capable Linux | 828 | * apm_cpu_idle - cpu idling for APM capable Linux |
@@ -1063,7 +1063,8 @@ static int apm_engage_power_management(u_short device, int enable) | |||
1063 | 1063 | ||
1064 | static int apm_console_blank(int blank) | 1064 | static int apm_console_blank(int blank) |
1065 | { | 1065 | { |
1066 | int error, i; | 1066 | int error = APM_NOT_ENGAGED; /* silence gcc */ |
1067 | int i; | ||
1067 | u_short state; | 1068 | u_short state; |
1068 | static const u_short dev[3] = { 0x100, 0x1FF, 0x101 }; | 1069 | static const u_short dev[3] = { 0x100, 0x1FF, 0x101 }; |
1069 | 1070 | ||
@@ -1104,7 +1105,8 @@ static int queue_empty(struct apm_user *as) | |||
1104 | 1105 | ||
1105 | static apm_event_t get_queued_event(struct apm_user *as) | 1106 | static apm_event_t get_queued_event(struct apm_user *as) |
1106 | { | 1107 | { |
1107 | as->event_tail = (as->event_tail + 1) % APM_MAX_EVENTS; | 1108 | if (++as->event_tail >= APM_MAX_EVENTS) |
1109 | as->event_tail = 0; | ||
1108 | return as->events[as->event_tail]; | 1110 | return as->events[as->event_tail]; |
1109 | } | 1111 | } |
1110 | 1112 | ||
@@ -1118,13 +1120,16 @@ static void queue_event(apm_event_t event, struct apm_user *sender) | |||
1118 | for (as = user_list; as != NULL; as = as->next) { | 1120 | for (as = user_list; as != NULL; as = as->next) { |
1119 | if ((as == sender) || (!as->reader)) | 1121 | if ((as == sender) || (!as->reader)) |
1120 | continue; | 1122 | continue; |
1121 | as->event_head = (as->event_head + 1) % APM_MAX_EVENTS; | 1123 | if (++as->event_head >= APM_MAX_EVENTS) |
1124 | as->event_head = 0; | ||
1125 | |||
1122 | if (as->event_head == as->event_tail) { | 1126 | if (as->event_head == as->event_tail) { |
1123 | static int notified; | 1127 | static int notified; |
1124 | 1128 | ||
1125 | if (notified++ == 0) | 1129 | if (notified++ == 0) |
1126 | printk(KERN_ERR "apm: an event queue overflowed\n"); | 1130 | printk(KERN_ERR "apm: an event queue overflowed\n"); |
1127 | as->event_tail = (as->event_tail + 1) % APM_MAX_EVENTS; | 1131 | if (++as->event_tail >= APM_MAX_EVENTS) |
1132 | as->event_tail = 0; | ||
1128 | } | 1133 | } |
1129 | as->events[as->event_head] = event; | 1134 | as->events[as->event_head] = event; |
1130 | if ((!as->suser) || (!as->writer)) | 1135 | if ((!as->suser) || (!as->writer)) |
@@ -1282,7 +1287,7 @@ static void standby(void) | |||
1282 | static apm_event_t get_event(void) | 1287 | static apm_event_t get_event(void) |
1283 | { | 1288 | { |
1284 | int error; | 1289 | int error; |
1285 | apm_event_t event; | 1290 | apm_event_t event = APM_NO_EVENTS; /* silence gcc */ |
1286 | apm_eventinfo_t info; | 1291 | apm_eventinfo_t info; |
1287 | 1292 | ||
1288 | static int notified; | 1293 | static int notified; |