The pageset array can potentially acquire a huge amount of memory on large
NUMA systems. F.e. on a system with 512 processors and 256 nodes there
will be 256*512 pagesets. If each pageset only holds 5 pages then we are
talking about 655360 pages.With a 16K page size on IA64 this results in
potentially 10 Gigabytes of memory being trapped in pagesets. The typical
cases are much less for smaller systems but there is still the potential of
memory being trapped in off node pagesets. Off node memory may be rarely
used if local memory is available and so we may potentially have memory in
seldom used pagesets without this patch.
The slab allocator flushes its per cpu caches every 2 seconds. The
following patch flushes the off node pageset caches in the same way by
tying into the slab flush.
The patch also changes /proc/zoneinfo to include the number of pages
currently in each pageset.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When using the early zone reclaim, it was noticed that allocating new pages
that should be spread across the whole system caused eviction of local pages.
This adds a new GFP flag to prevent early reclaim from happening during
certain allocation attempts. The example that is implemented here is for page
cache pages. We want page cache pages to be spread across the whole system,
and we don't want page cache pages to evict other pages to get local memory.
Signed-off-by: Martin Hicks <mort@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Mempools have 2 problems.
The first is that mempool_alloc can possibly get stuck in __alloc_pages
when they should opt to fail, and take an element from their reserved pool.
The second is that it will happily eat emergency PF_MEMALLOC reserves
instead of going to their reserved pools.
Fix the first by passing __GFP_NORETRY in the allocation calls in
mempool_alloc. Fix the second by introducing a __GFP_MEMPOOL flag which
directs the page allocator not to allocate from the reserve pool.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Christoph Lameter