Messages in this thread | | | Date | Fri, 27 Mar 2009 15:10:56 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: ext3 IO latency measurements (was: Linux 2.6.29) |
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On Fri, 27 Mar 2009, Jan Kara wrote: > > Doable but not fairly simple ;) Firstly you have to restart a transaction > when you've used up all the credits you originally started with (easy), > secondly ext3 uses lock order PageLock -> "transaction start" which is > unusable for the scheme you suggest. So we'd have to revert that - which > needs larger audit of our locking scheme and that's probably the reason > why noone has done it yet.
It's also not clear that ext3 can really do much better than the regular generic_writepages() logic. I mean, seriously, what's there to improve on? The transaction code is all normally totally pointless, and I merged the patch that avoids it when not necessary.
It might be different if more people used "data=journal", but I don't doubt that is very common. For data=writeback and data=ordered, I bet generic_writepages() is as good as anything ext3-specific could be.
Linus
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