Messages in this thread | | | From | Daniel Phillips <> | Subject | Re: [patch 6/12] hold atomic kmaps across generic_file_read | Date | Sun, 11 Aug 2002 10:00:06 +0200 |
| |
On Sunday 11 August 2002 00:42, Linus Torvalds wrote: > For example, what do you do when somebody has a COW-page mapped into it's > VM space and you want to start paging stuff out?
Clearly it requires a CoW break and swapping out that page won't free any memory directly, but it will in turn allow the cache page to be dropped. I suppose your point is that these ideas touch the system in a lot of places, and right now the code is a little too irregular to withstand lathering on a new layer of cruft. That's true, but <plug>the reverse mapping work enables some fundamental VM simplifications that make a lot of things more local, and so a better base for these new, sophisticated features is on its way.</plug>
> There are "interesting" > cases that just may mean that doing the COW thing is a really stupid thing > to do, even if it is intriguing to _think_ about it.
It is good sport, but the real benefits are compelling and will only get more so. For high end scientific uses (read supercomputing clusters) it's a cinch developers will prefer high speed file operations that turn in nearly the same raw performance on large transfers as O_DIRECT while not bypassing the file cache.
-- 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/
| |