Messages in this thread | | | Date | Fri, 10 Dec 1999 09:18:04 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: mmap on a device returns ENODEV |
| |
On Fri, 10 Dec 1999, Ingo Molnar wrote: > > the attached small patch against 2.3.32-pre2 adds all pagecache blocks > that have established mappings to the buffer-cache hashlists (and can thus > can be looked up), including the swapcache. It works fine here and there > is no noticeable slowdown anywhere.
I really don't like this. It shouldn't be needed, and it does slow down lookups (the fact that we no longer do buffer cache lookups as often as we historically did hides the issue, but it's still conceptually wrong).
I think we should synchronize only through the page cache, and in cases where that is impossible (ie different indices - a file vs a raw device) we should not even try. Synchronization is not only expensive, it tends to come and bite you later when you want to do something really clever. So don't try to maintain coherency unless absolutely 100% _required_ - and I don't think it is required at all in this case.
Linus
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |