[lkml]   [2001]   [May]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [patch] severe softirq handling performance bug, fix, 2.4.5

On Sun, 27 May 2001, Andrea Arcangeli wrote:

> I mean everything is fine until the same softirq is marked active
> again under do_softirq, in such case neither the do_softirq in do_IRQ
> will run it (because we are in the critical section and we hold the
> per-cpu locks), nor we will run it again ourself from the underlying
> do_softirq to avoid live locking into do_softirq.

if you mean the stock kernel, this scenario you describe is not how it
behaves, because only IRQ contexts can mark a softirq active again. And
those IRQ contexts will run do_IRQ() naturally, so while *this*
do_softirq() invocation wont run those reactivated softirqs, the IRQ
context that just triggered the softirq will do so.

the real source of softirq latencies is the local_bh_disable()/enable()
behavior, see my previous patch.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 12:54    [W:0.114 / U:5.428 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site