Messages in this thread | | | Subject | Re: [PATCH linux-2.6.0-test10-mm1] filemap_fdatawait.patch | From | Daniel McNeil <> | Date | 17 Dec 2003 11:25:05 -0800 |
| |
On Tue, 2003-12-16 at 18:03, Andrew Morton wrote: > Daniel McNeil <daniel@osdl.org> wrote: > > > > I have found something else that might be causing the problem. > > filemap_fdatawait() skips pages that are not marked PG_writeback. > > However, when a page is going to be written, PG_dirty is cleared > > before PG_writeback is set (while the PG_locked is set). So it > > looks like filemap_fdatawait() can see a page just before it is > > going to be written and not wait for it. Here is a patch that > > makes filemap_fdatawait() wait for locked pages as well to make > > sure it does not missed any pages. > > This filemap_fdatawait() behaviour is as-designed. That function is only > responsible for waiting on I/O which was initiated prior to it being > invoked. Because it is designed for fsync(), fdatasync(), O_SYNC, msync(), > sync(), etc. > > Now, it could be that this behaviour is not appropriate for the O_DIRECT > sync function - the result of your testing will be interesting. >
My tests still failed overnight. I was thinking that maybe a non-blocking do_writepages() was happening at the same time as the filemap_fdatawrite()/filemap_fdatawait(), so even though the page was dirty before the filemap_fdatawrite(), it was missed.
Daniel
- 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/
| |