On Mon, 17 Sep 2007 13:11:14 -0400 Rik van Riel <[EMAIL PROTECTED]> wrote:
> > I'm guessing there is no pressure at all on zone_highmem so the > > kernel will not try to reclaim pagecache. And because the pagecache > > pages are happily sitting there, the buggerheads are pinned and do not > > get reclaimed. yeah, this got pretty unavoidably broken when we killed the global LRU in 2.5.early. It's odd that it took this long for someone to hit it. > I've got code for this in RHEL 3, but never bothered to > merge it upstream since I thought people with large memory > systems would be running 64 bit kernels by now. > > Obviously I was wrong. Andrew, are you interested in a > fix for this problem? > > IIRC I simply kept a list of all buffer heads and walked > that to reclaim pages when the number of buffer heads is > too high (and we need memory). This list can be maintained > in places where we already hold the lock for the buffer head > freelist, so there should be no additional locking overhead > (again, IIRC). Christoph's slab defragmentation code should permit us to fix this: grab a page of buffer_heads off the slab lists, trylock the page, strip the buffer_heads. I think that would be a better approach if we can get it going because it's more general. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
