Messages in this thread Patch in this message | | | From | Anna-Maria Behnsen <> | Subject | [PATCH v5 06/18] add_timer_on(): Make sure callers have TIMER_PINNED flag | Date | Wed, 1 Mar 2023 15:17:32 +0100 |
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The implementation of the hierachical timer pull model will change the timer bases per CPU. Timers, that have to expire on a specific CPU, require the TIMER_PINNED flag. Otherwise they will be queued on the dedicated CPU but in global timer base and those timers could also expire on other CPUs. Timers with TIMER_DEFERRABLE flag end up in a separate base anyway and are executed on the local CPU only.
Therefore add the missing TIMER_PINNED flag for those callers who use add_timer_on() without the flag. No functional change.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: x86@kernel.org Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: "Jason A. Donenfeld" <Jason@zx2c4.com> Cc: John Stultz <jstultz@google.com> Cc: Stephen Boyd <sboyd@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> --- v5: Add comment in workqueue.c that it's only a workaround for now --- arch/x86/kernel/tsc_sync.c | 3 ++- drivers/char/random.c | 2 +- kernel/time/clocksource.c | 2 +- kernel/workqueue.c | 15 +++++++++++++-- 4 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/tsc_sync.c b/arch/x86/kernel/tsc_sync.c index 9452dc9664b5..eab827288e0f 100644 --- a/arch/x86/kernel/tsc_sync.c +++ b/arch/x86/kernel/tsc_sync.c @@ -110,7 +110,8 @@ static int __init start_sync_check_timer(void) if (!cpu_feature_enabled(X86_FEATURE_TSC_ADJUST) || tsc_clocksource_reliable) return 0; - timer_setup(&tsc_sync_check_timer, tsc_sync_check_timer_fn, 0); + timer_setup(&tsc_sync_check_timer, tsc_sync_check_timer_fn, + TIMER_PINNED); tsc_sync_check_timer.expires = jiffies + SYNC_CHECK_INTERVAL; add_timer(&tsc_sync_check_timer); diff --git a/drivers/char/random.c b/drivers/char/random.c index ce3ccd172cc8..db6a7c0695de 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1007,7 +1007,7 @@ static DEFINE_PER_CPU(struct fast_pool, irq_randomness) = { #define FASTMIX_PERM HSIPHASH_PERMUTATION .pool = { HSIPHASH_CONST_0, HSIPHASH_CONST_1, HSIPHASH_CONST_2, HSIPHASH_CONST_3 }, #endif - .mix = __TIMER_INITIALIZER(mix_interrupt_randomness, 0) + .mix = __TIMER_INITIALIZER(mix_interrupt_randomness, TIMER_PINNED) }; /* diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 91836b727cef..e982c119e3c9 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -561,7 +561,7 @@ static inline void clocksource_start_watchdog(void) { if (watchdog_running || !watchdog || list_empty(&watchdog_list)) return; - timer_setup(&watchdog_timer, clocksource_watchdog, 0); + timer_setup(&watchdog_timer, clocksource_watchdog, TIMER_PINNED); watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL; add_timer_on(&watchdog_timer, cpumask_first(cpu_online_mask)); watchdog_running = 1; diff --git a/kernel/workqueue.c b/kernel/workqueue.c index b8b541caed48..a428d94084ee 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1677,10 +1677,21 @@ static void __queue_delayed_work(int cpu, struct workqueue_struct *wq, dwork->cpu = cpu; timer->expires = jiffies + delay; - if (unlikely(cpu != WORK_CPU_UNBOUND)) + if (unlikely(cpu != WORK_CPU_UNBOUND)) { + /* + * TODO: Setting the flag is a workaround for now; needs to + * be cleaned up with new work initializers and defines + */ + timer->flags |= TIMER_PINNED; add_timer_on(timer, cpu); - else + } else { + /* + * TODO: Resetting the flag is a workaround for now; needs + * to be cleaned up with new work initializers and defines + */ + timer->flags &= ~TIMER_PINNED; add_timer(timer); + } } /** -- 2.30.2
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