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authorLinus Torvalds <torvalds@linux-foundation.org>2013-11-14 16:30:30 +0900
committerLinus Torvalds <torvalds@linux-foundation.org>2013-11-14 16:30:30 +0900
commit5e30025a319910695f5010dc0fb53a23299da14d (patch)
tree4292bcf78de221c7de1774ccf5ad0ac5a9315c26 /arch/x86
parent7971e23a66c94f1b9bd2d64a3e86dfbfa8c60121 (diff)
parent90d3839b90fe379557dae4a44735a6af78f42885 (diff)
Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core locking changes from Ingo Molnar: "The biggest changes: - add lockdep support for seqcount/seqlocks structures, this unearthed both bugs and required extra annotation. - move the various kernel locking primitives to the new kernel/locking/ directory" * 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits) block: Use u64_stats_init() to initialize seqcounts locking/lockdep: Mark __lockdep_count_forward_deps() as static lockdep/proc: Fix lock-time avg computation locking/doc: Update references to kernel/mutex.c ipv6: Fix possible ipv6 seqlock deadlock cpuset: Fix potential deadlock w/ set_mems_allowed seqcount: Add lockdep functionality to seqcount/seqlock structures net: Explicitly initialize u64_stats_sync structures for lockdep locking: Move the percpu-rwsem code to kernel/locking/ locking: Move the lglocks code to kernel/locking/ locking: Move the rwsem code to kernel/locking/ locking: Move the rtmutex code to kernel/locking/ locking: Move the semaphore core to kernel/locking/ locking: Move the spinlock code to kernel/locking/ locking: Move the lockdep code to kernel/locking/ locking: Move the mutex code to kernel/locking/ hung_task debugging: Add tracepoint to report the hang x86/locking/kconfig: Update paravirt spinlock Kconfig description lockstat: Report avg wait and hold times lockdep, x86/alternatives: Drop ancient lockdep fixup message ...
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/Kconfig6
-rw-r--r--arch/x86/kernel/alternative.c11
-rw-r--r--arch/x86/vdso/vclock_gettime.c8
3 files changed, 7 insertions, 18 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 14dc9c797abb..6e3e1cb3f6a0 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -635,10 +635,10 @@ config PARAVIRT_SPINLOCKS
spinlock implementation with something virtualization-friendly
(for example, block the virtual CPU rather than spinning).
- Unfortunately the downside is an up to 5% performance hit on
- native kernels, with various workloads.
+ It has a minimal impact on native kernels and gives a nice performance
+ benefit on paravirtualized KVM / Xen kernels.
- If you are unsure how to answer this question, answer N.
+ If you are unsure how to answer this question, answer Y.
source "arch/x86/xen/Kconfig"
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 15e8563e5c24..df94598ad05a 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -402,17 +402,6 @@ void alternatives_enable_smp(void)
{
struct smp_alt_module *mod;
-#ifdef CONFIG_LOCKDEP
- /*
- * Older binutils section handling bug prevented
- * alternatives-replacement from working reliably.
- *
- * If this still occurs then you should see a hang
- * or crash shortly after this line:
- */
- pr_info("lockdep: fixing up alternatives\n");
-#endif
-
/* Why bother if there are no other CPUs? */
BUG_ON(num_possible_cpus() == 1);
diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index 72074d528400..2ada505067cc 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -178,7 +178,7 @@ notrace static int __always_inline do_realtime(struct timespec *ts)
ts->tv_nsec = 0;
do {
- seq = read_seqcount_begin(&gtod->seq);
+ seq = read_seqcount_begin_no_lockdep(&gtod->seq);
mode = gtod->clock.vclock_mode;
ts->tv_sec = gtod->wall_time_sec;
ns = gtod->wall_time_snsec;
@@ -198,7 +198,7 @@ notrace static int do_monotonic(struct timespec *ts)
ts->tv_nsec = 0;
do {
- seq = read_seqcount_begin(&gtod->seq);
+ seq = read_seqcount_begin_no_lockdep(&gtod->seq);
mode = gtod->clock.vclock_mode;
ts->tv_sec = gtod->monotonic_time_sec;
ns = gtod->monotonic_time_snsec;
@@ -214,7 +214,7 @@ notrace static int do_realtime_coarse(struct timespec *ts)
{
unsigned long seq;
do {
- seq = read_seqcount_begin(&gtod->seq);
+ seq = read_seqcount_begin_no_lockdep(&gtod->seq);
ts->tv_sec = gtod->wall_time_coarse.tv_sec;
ts->tv_nsec = gtod->wall_time_coarse.tv_nsec;
} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
@@ -225,7 +225,7 @@ notrace static int do_monotonic_coarse(struct timespec *ts)
{
unsigned long seq;
do {
- seq = read_seqcount_begin(&gtod->seq);
+ seq = read_seqcount_begin_no_lockdep(&gtod->seq);
ts->tv_sec = gtod->monotonic_time_coarse.tv_sec;
ts->tv_nsec = gtod->monotonic_time_coarse.tv_nsec;
} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));