Re: 0-order allocation problem

[Hugh Dickins <hugh@veritas.com>]

On Wed, 15 Aug 2001, Marcelo Tosatti wrote:
> 
> Hugh, could you check which kind of allocation is failing and from where?
> (allocation flags, etc).

Whenever I looked the allocation flags were 0x70,
__GFP_IO|__GFP_HIGH|__GFP_WAIT; but presumably PF_MEMALLOC too.

What I was doing was running a memory hog (for 600MB with 256MB
RAM and 512MB swap), exiting that, doing swapoff -a and swapon -a
(being interested in timing different swapoff methods).  First
run no problem at all, but when immediately run again after,
collapsed into endless 0-order allocation failure messages.
Didn't happen in 2.4.8.  Linus' patch to 2.4.9-pre4 gets it
back to work again, after a burst of those messages.

The stack trace was usually some high-level function, _alloc_pages,
__alloc_pages, try_to_free_pages, do_try_to_free_pages, page_launder,
swap_writepage, rw_swap_page, rw_swap_page_base, brw_page,
create_empty_buffers, create_buffers, get_unused_buffer_head,
kmem_cache_alloc, kmem_cache_grow, __get_free_pages,
_alloc_pages, __alloc_pages, printk.

But on one occasion it was kswapd calling
do_try_to_free_pages, page_launder, swap_writepage... as above.

Hugh

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/