tree 40f2bbbe7c59fb4b4a44120fa9cc79822b68e545
parent 0e2e63dd608bf5844ffae7bf7d860de18a62724c
author Peter Zijlstra <a.p.zijlstra@chello.nl> 1274365315 +0200
committer Ingo Molnar <mingo@elte.hu> 1274434678 +0200

perf: Fix wakeup storm for RO mmap()s

RO mmap()s don't update the tail pointer, so
comparing against it for determining the written data
size doesn't really do any good.

Keep track of when we last did a wakeup, and compare
against that.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20100521090710.684479310@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>