On Fri, 2 Mar 2007 10:15:36 -0800 (PST) Christoph Lameter <[EMAIL PROTECTED]> wrote:
> On Fri, 2 Mar 2007, Andrew Morton wrote: > > > > One particular case is a 32GB system with a database that takes most > > > of memory. The amount of actually freeable page cache memory is in > > > the hundreds of MB. > > > > Where's the rest of the memory? tmpfs? mlocked? hugetlb? > > The memory is likely in use but there is enough memory free in unmapped > clean pagecache pages so that we occasionally are able to free pages. Then > the app is reading more from disk replenishing that ... > Thus we are forever cycling through the LRU lists moving pages between > the lists aging etc etc. Can lead to a livelock. Guys, with this level of detail thses problems will never be fixed. > > > A third scenario is where a system has way more RAM than swap, and not > > > a whole lot of freeable page cache. In this case, the VM ends up > > > spending WAY too much CPU time scanning and shuffling around essentially > > > unswappable anonymous memory and tmpfs files. > > > > Well we've allegedly fixed that, but it isn't going anywhere without > > testing. > > We have fixed the case in which we compile the kernel without swap. Then > anonymous pages behave like mlocked pages. Did we do more than that? oh yeah, we took the ran-out-of-swapcache code out. But if we're going to do this thing, we should find some way to bring it back. - 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/
