Messages in this thread | | | Date | Wed, 14 Aug 2013 23:18:01 -0700 (PDT) | From | David Lang <> | Subject | Re: page fault scalability (ext3, ext4, xfs) |
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On Wed, 14 Aug 2013, Andy Lutomirski wrote:
>> The big problem with this approach is that not doing the >> timestamp update on page faults is going to break the inode change >> version counting because for ext4, btrfs and XFS it takes a >> transaction to bump that counter. NFS needs to know the moment a >> file is changed in memory, not when it is written to disk. Also, NFS >> requires the change to the counter to be persistent over server >> failures, so it needs to be changed as part of a transaction.... > > NFS can do whatever it wants, although I suspect that even NFS can get > away with deferring cmtime updates.
NFS already has to do syncs to make sure the data is safe on disk, have a flag that NFS can use to make the ctime safe, everyone else can get the performance improvement and NFS can have it's slow-but-safe approach.
David Lang
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