Messages in this thread | | | Date | Thu, 1 Jul 2010 13:33:42 +1000 | From | Dave Chinner <> | Subject | Re: [patch 52/52] fs: icache less I_FREEING time |
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On Wed, Jun 30, 2010 at 10:14:52PM +1000, Nick Piggin wrote: > On Wed, Jun 30, 2010 at 08:13:54PM +1000, Dave Chinner wrote: > > On Thu, Jun 24, 2010 at 01:03:04PM +1000, npiggin@suse.de wrote: > > > Problem with inode reclaim is that it puts inodes into I_FREEING state > > > and then continues to gather more, during which it may iput, > > > invalidate_mapping_pages, be preempted, etc. Holding these inodes in > > > I_FREEING can cause pauses. > > > > What sort of pauses? I can't see how holding a few inodes in > > I_FREEING state would cause any serious sort of holdoff... > > Well if the inode is accessed again, it has to wait for potentially > hundreds of inodes to be found from the LRU, pagecache invalidated, > and destroyed.
So it's a theoretical concern you have, not something that's actually been demonstrated as a problem?
As it is, If the inode is accessed immediately after teardown has started, then we failed to hold on to the inode at a higher level for long enough. Changing the I_FREEING behaviour is trying to address the issue at the wrong level...
Cheers,
Dave. -- Dave Chinner david@fromorbit.com
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