]> git.hungrycats.org Git - linux/commit
[PATCH] softirqs: fix latency of softirq processing
authorIngo Molnar <mingo@elte.hu>
Mon, 18 Oct 2004 15:53:48 +0000 (08:53 -0700)
committerLinus Torvalds <torvalds@ppc970.osdl.org>
Mon, 18 Oct 2004 15:53:48 +0000 (08:53 -0700)
commit40e39ce0f4eceee04555c45ae9918a017cd1686c
tree7b504b25b0669020a739e5618b098f473d37fe10
parentcfc4f957ff7bffa6aaf7e4029ee9c8689b43c366
[PATCH] softirqs: fix latency of softirq processing

The attached patch fixes a local_bh_enable() buglet: we first enabled
softirqs then did we do local_softirq_pending() - often this is preemptible
code.  So this task could be preempted and there's no guarantee that
softirq processing will occur (except the periodic timer tick).

The race window is small but existent.  This could result in packet
processing latencies or timer expiration latencies - hard to detect and
annoying bugs.

The fix is to invoke softirqs with softirqs enabled but preemption still
disabled.  Patch is against 2.6.9-rc2-mm1.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
kernel/softirq.c