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| author | Andreas Mohr <andi@rhlx01.fht-esslingen.de> | 2006-06-25 14:46:52 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-06-25 19:00:55 +0200 |
| commit | 186989177e627c2571a3026d39ea1433e4ddc097 (patch) | |
| tree | facbda2b471468dfc3b483c6711094e8495e0eec /arch/i386 | |
| parent | [PATCH] Clean up and refactor i386 sub-architecture setup (diff) | |
| download | linux-186989177e627c2571a3026d39ea1433e4ddc097.tar.xz linux-186989177e627c2571a3026d39ea1433e4ddc097.zip | |
[PATCH] cpu_relax(): smpboot.c
Add cpu_relax() to various smpboot.c init loops. cpu_relax() always implies a
barrier (according to Arjan), so remove those as well.
Signed-off-by: Andreas Mohr <andi@lisas.de>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386')
| -rw-r--r-- | arch/i386/kernel/smpboot.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c index 825b2b4ca721..bd0ca5c9f053 100644 --- a/arch/i386/kernel/smpboot.c +++ b/arch/i386/kernel/smpboot.c @@ -257,7 +257,7 @@ static void __init synchronize_tsc_bp (void) * all APs synchronize but they loop on '== num_cpus' */ while (atomic_read(&tsc_count_start) != num_booting_cpus()-1) - mb(); + cpu_relax(); atomic_set(&tsc_count_stop, 0); wmb(); /* @@ -276,7 +276,7 @@ static void __init synchronize_tsc_bp (void) * Wait for all APs to leave the synchronization point: */ while (atomic_read(&tsc_count_stop) != num_booting_cpus()-1) - mb(); + cpu_relax(); atomic_set(&tsc_count_start, 0); wmb(); atomic_inc(&tsc_count_stop); @@ -333,19 +333,21 @@ static void __init synchronize_tsc_ap (void) * this gets called, so we first wait for the BP to * finish SMP initialization: */ - while (!atomic_read(&tsc_start_flag)) mb(); + while (!atomic_read(&tsc_start_flag)) + cpu_relax(); for (i = 0; i < NR_LOOPS; i++) { atomic_inc(&tsc_count_start); while (atomic_read(&tsc_count_start) != num_booting_cpus()) - mb(); + cpu_relax(); rdtscll(tsc_values[smp_processor_id()]); if (i == NR_LOOPS-1) write_tsc(0, 0); atomic_inc(&tsc_count_stop); - while (atomic_read(&tsc_count_stop) != num_booting_cpus()) mb(); + while (atomic_read(&tsc_count_stop) != num_booting_cpus()) + cpu_relax(); } } #undef NR_LOOPS @@ -1433,7 +1435,7 @@ int __devinit __cpu_up(unsigned int cpu) /* Unleash the CPU! */ cpu_set(cpu, smp_commenced_mask); while (!cpu_isset(cpu, cpu_online_map)) - mb(); + cpu_relax(); return 0; } |