Messages in this thread | | | Date | Fri, 11 Dec 1998 08:52:06 +0000 | From | Jamie Lokier <> | Subject | Re: Concurrent read/writes on the same file |
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On Wed, Dec 09, 1998 at 11:50:02AM +0000, Stephen C. Tweedie wrote: > On Wed, 9 Dec 1998 16:55:30 +1300, Chris Wedgwood <cw@ix.net.nz> said: > > What about one reader and one writer -- here I assume the read is > > locked, or do we just get trashed data? (Assuming we do, its still > > OK, it really up to an application to not read/write to a file at the > > same time and expect consistency). > > No automatic locking is done in the kernel for this case. Use kernel > record locking with flock/fcntl if you want that: that's what it's > there for! > > I've considered it more than once, but the performance penalty of > doing range locking is too high --- it pollutes the fast path of > accessing data in the cache --- and locking the entire inode destroys > parallelism.
I thought one of the fundamentals was that read/write were atomic, if they're not interrupted.
Wouldn't a per-inode rwlock_t be efficient for this? (Instead of the current per-inode writer semaphore).
-- Jamie
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