Messages in this thread | ![/](/images/icornerl.gif) | | Date | Fri, 10 Oct 2003 19:53:43 -0700 | From | Andrew Morton <> | Subject | Re: statfs() / statvfs() syscall ballsup... |
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Trond Myklebust <trond.myklebust@fys.uio.no> wrote: > > It does nothing for the case Joel mentioned where 2 different nodes > are writing to the same device, and you need to force a read in order > to resynchronize the page cache. > Apart from O_DIRECT, we have nothing in the kernel as it stands that > will allow userland to deal with this case.
Applications may use fadvise(POSIX_FADV_DONTNEED) to invalidate sections of a file's pagecache.
It is not designed to be 100% reliable though: mmapped pages will be retained, and dirty pages are skipped.
For the dirty pages it might be useful to add a new mode to fadvise which syncs a section of a file's pages; -mm has the necessary infrastructure for that.
POSIX does not define the fadvise() semantics very clearly, so it is largely up to us to decide what makes sense. There are a number of things which we can do quite easily in there - it's mainly a matter of working out exactly what we want to do.
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