Re: [PATCH 2/2] block: Convert BDI proportion calculations to flexible proportions
From: Peter Zijlstra <peterz@infradead.org>
Date: 2012-05-31 22:26:17
Also in:
lkml
On Fri, 2012-06-01 at 00:11 +0200, Jan Kara wrote:
quoted hunk ↗ jump to hunk
bool fprop_new_period(struct fprop_global *p, int periods) { - u64 events = percpu_counter_sum(&p->events); + u64 events; + unsigned long flags; + local_irq_save(flags); + events = percpu_counter_sum(&p->events); + local_irq_restore(flags); /* * Don't do anything if there are no events. */@@ -73,7 +77,9 @@ bool fprop_new_period(struct fprop_global *p, int periods) if (periods < 64) events -= events >> periods; /* Use addition to avoid losing events happening between sum and set */ + local_irq_save(flags); percpu_counter_add(&p->events, -events); + local_irq_restore(flags); p->period += periods; write_seqcount_end(&p->sequence);
Uhm, why bother enabling it in between? Just wrap the whole function in a single IRQ disable. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>