Messages in this thread | | | Date | Wed, 07 Dec 2005 09:18:56 -0500 | From | Peter Staubach <> | Subject | Re: another nfs puzzle |
| |
Trond Myklebust wrote:
>On Wed, 2005-12-07 at 09:01 -0500, Peter Staubach wrote: > > >>Kenny Simpson wrote: >> >> >> >>>Hi again, >>> I am seeing some odd behavior with O_DIRECT. If a file opened with O_DIRECT has a page mmap'd, >>>and the file is extended via pwrite, then the mmap'd region seems to get lost - i.e. it neither >>>takes up system memory, nor does it get written out. >>> >>> >>> >>> >>I don't think that I understand why or how the kernel allows a file, >>which was opened with O_DIRECT, to be mmap'd. The use of O_DIRECT >>implies no caching and mmap implies the use of caching. >> >> > >In this context it doesn't matter whether or not the you use the same >file descriptor. The problem is the same if my process opens the file >for O_DIRECT and then your process open it for normal I/O, and mmaps it. >
Yup, same problem. Why is this allowed? Does it really work correctly?
Thanx...
ps - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |