92 lines
3.1 KiB
Diff
92 lines
3.1 KiB
Diff
Subject: ia64: vsyscall: Use seqcount instead of seqlock
|
|
From: Thomas Gleixner <tglx@linutronix.de>
|
|
Date: Tue, 28 Feb 2012 18:33:08 +0100
|
|
|
|
The update of the vdso data happens under xtime_lock, so adding a
|
|
nested lock is pointless. Just use a seqcount to sync the readers.
|
|
|
|
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
|
Cc: Tony Luck <tony.luck@intel.com>
|
|
---
|
|
arch/ia64/kernel/asm-offsets.c | 4 ++--
|
|
arch/ia64/kernel/fsys.S | 2 +-
|
|
arch/ia64/kernel/fsyscall_gtod_data.h | 2 +-
|
|
arch/ia64/kernel/time.c | 10 +++-------
|
|
4 files changed, 7 insertions(+), 11 deletions(-)
|
|
|
|
Index: linux-2.6/arch/ia64/kernel/asm-offsets.c
|
|
===================================================================
|
|
--- linux-2.6.orig/arch/ia64/kernel/asm-offsets.c
|
|
+++ linux-2.6/arch/ia64/kernel/asm-offsets.c
|
|
@@ -269,8 +269,8 @@ void foo(void)
|
|
BLANK();
|
|
|
|
/* used by fsys_gettimeofday in arch/ia64/kernel/fsys.S */
|
|
- DEFINE(IA64_GTOD_LOCK_OFFSET,
|
|
- offsetof (struct fsyscall_gtod_data_t, lock));
|
|
+ DEFINE(IA64_GTOD_SEQ_OFFSET,
|
|
+ offsetof (struct fsyscall_gtod_data_t, seq);
|
|
DEFINE(IA64_GTOD_WALL_TIME_OFFSET,
|
|
offsetof (struct fsyscall_gtod_data_t, wall_time));
|
|
DEFINE(IA64_GTOD_MONO_TIME_OFFSET,
|
|
Index: linux-2.6/arch/ia64/kernel/fsys.S
|
|
===================================================================
|
|
--- linux-2.6.orig/arch/ia64/kernel/fsys.S
|
|
+++ linux-2.6/arch/ia64/kernel/fsys.S
|
|
@@ -174,7 +174,7 @@ ENTRY(fsys_set_tid_address)
|
|
FSYS_RETURN
|
|
END(fsys_set_tid_address)
|
|
|
|
-#if IA64_GTOD_LOCK_OFFSET !=0
|
|
+#if IA64_GTOD_SEQ_OFFSET !=0
|
|
#error fsys_gettimeofday incompatible with changes to struct fsyscall_gtod_data_t
|
|
#endif
|
|
#if IA64_ITC_JITTER_OFFSET !=0
|
|
Index: linux-2.6/arch/ia64/kernel/fsyscall_gtod_data.h
|
|
===================================================================
|
|
--- linux-2.6.orig/arch/ia64/kernel/fsyscall_gtod_data.h
|
|
+++ linux-2.6/arch/ia64/kernel/fsyscall_gtod_data.h
|
|
@@ -6,7 +6,7 @@
|
|
*/
|
|
|
|
struct fsyscall_gtod_data_t {
|
|
- seqlock_t lock;
|
|
+ seqcount_t seq;
|
|
struct timespec wall_time;
|
|
struct timespec monotonic_time;
|
|
cycle_t clk_mask;
|
|
Index: linux-2.6/arch/ia64/kernel/time.c
|
|
===================================================================
|
|
--- linux-2.6.orig/arch/ia64/kernel/time.c
|
|
+++ linux-2.6/arch/ia64/kernel/time.c
|
|
@@ -35,9 +35,7 @@
|
|
|
|
static cycle_t itc_get_cycles(struct clocksource *cs);
|
|
|
|
-struct fsyscall_gtod_data_t fsyscall_gtod_data = {
|
|
- .lock = __SEQLOCK_UNLOCKED(fsyscall_gtod_data.lock),
|
|
-};
|
|
+struct fsyscall_gtod_data_t fsyscall_gtod_data;
|
|
|
|
struct itc_jitter_data_t itc_jitter_data;
|
|
|
|
@@ -460,9 +458,7 @@ void update_vsyscall_tz(void)
|
|
void update_vsyscall(struct timespec *wall, struct timespec *wtm,
|
|
struct clocksource *c, u32 mult)
|
|
{
|
|
- unsigned long flags;
|
|
-
|
|
- write_seqlock_irqsave(&fsyscall_gtod_data.lock, flags);
|
|
+ write_seqcount_begin(&fsyscall_gtod_data.seq);
|
|
|
|
/* copy fsyscall clock data */
|
|
fsyscall_gtod_data.clk_mask = c->mask;
|
|
@@ -485,6 +481,6 @@ void update_vsyscall(struct timespec *wa
|
|
fsyscall_gtod_data.monotonic_time.tv_sec++;
|
|
}
|
|
|
|
- write_sequnlock_irqrestore(&fsyscall_gtod_data.lock, flags);
|
|
+ write_seqcount_end(&fsyscall_gtod_data.seq);
|
|
}
|
|
|