On Sat, 30 Dec 2000, Alexander Viro wrote:
> On 30 Dec 2000, Linus Torvalds wrote:
> > There are other, equally likely, candidates for these kinds of stalls:
> > - filesystem locks. Especially the ext2 superblock lock. You can easily
> > hit this one, as some ext2 functions actually do a lot of IO while
> > holding the lock.
> Hmm... In 2.4 we can make the situation with superblock lock on ext2
> much better.
Actually, 2.4.x right now is worse than 2.2.x in this regard, for a really
simple reason: 2.2.x will only do the equivalent of "rebalance_dirty" when
it dirties a previously clean buffer. The current 2.4.x code does that
regardless of whether the buffer was dirty before or not.
I want to see your patches to fix this for good in a 2.5.x timeframe (or,
if they are really clean and obvious, at a later 2.4.x date), but for
2.4.x I think that we'll do either "remove rebalance dirty completely" or
at the very least we'll not re-balance for re-dirtying a dirty buffer.
The re-dirtying a dirty buffer is the common case for the superblock
stuff: bitmap blocks etc are often dirty already, _especially_ in the case
of an active writer. So 2.4.x is actually more likely to hit the
Of course, 2.4.x has had so many improvements in file writing memory
pressure that it might not end up being that noticeable, but even so..
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