Messages in this thread |  | | Date | Sat, 30 Dec 2000 14:25:49 -0500 (EST) | From | Alexander Viro <> | Subject | Re: 2.2.19pre3 and poor reponse to RT-scheduled processes? |
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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. I didn't go the whole way down to spinlocks, but right now I'm sitting on a box with modified ext2 that doesn't do _any_ IO in protected parts of ext2_new_inode()/ext2_new_block(). I can try to extract the relevant parts of the patch if you are interested (it also got directories-in-pagecache stuff and better SMP threading of get_block()/truncate()). The thing seems to be working fine and I see no serious contention on lock_super(). Dunno if it's worth doing before 2.4.0, but since it has zero impact on the rest of tree (OK, zero except that write_on_page() had been exported, but I could trivially get rid of that)... Maybe 2.4.early would be a good idea. Cheers, Al
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