On Thu, 12 Apr 2007 09:39:25 +0200 Peter Zijlstra <[EMAIL PROTECTED]> wrote:
> On Wed, 2007-04-11 at 15:30 -0700, Andrew Morton wrote: > > > There used to be a cond_resched() in invalidate_mapping_pages() which would > > have prevented this, but I rudely removed it to support > > /proc/sys/vm/drop_caches (which needs to call invalidate_inode_pages() > > under spinlock). > > > > We could resurrect that cond_resched() by passing in some flag, I guess. > > Or change the code to poke the softlockup detector. The former would be > > better. > > cond_resched() is conditional on __resched_legal(0) What's __resched_legal()? > which should take > care of being called under a spinlock. We only increment preempt_count() in spin_lock() if CONFIG_PREEMPT. > so I guess we can just reinstate the call in invalidate_mapping_pages() > > (still waiting on the compile to finish...) > --- > invalidate_mapping_pages() is called under locks (usually preemptable) > but can do a _lot_ of work, stick in a voluntary preemption point to > avoid excessive latencies (over 10 seconds was reported by softlockup). > > Signed-off-by: Peter Zijlstra <[EMAIL PROTECTED]> > --- > mm/truncate.c | 2 ++ > 1 file changed, 2 insertions(+) > > Index: linux-2.6-mm/mm/truncate.c > =================================================================== > --- linux-2.6-mm.orig/mm/truncate.c > +++ linux-2.6-mm/mm/truncate.c > @@ -292,6 +292,8 @@ unsigned long invalidate_mapping_pages(s > pgoff_t index; > int lock_failed; > > + cond_resched(); > + > lock_failed = TestSetPageLocked(page); Is deadlocky on the drop_caches path and if CONFIG_PREEMPT we'll get scheduling-in-spinlock warnings. For the blkdev_close() path the change is unneeded if CONFIG_PREEMPT and will fix things if !CONFIG_PREEMPT. We can presumably just remove the invalidate_mapping_pages() call from the kill_bdev() path (at least) - kill_bdev()'s truncate_inode_pages() will do the same thing. It might be time to remove that unused-for-six-years destroy_dirty_buffers too. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
