Hi Alan,
here's the patch for the 2.2.15* out of memory problem.
This patch does a number of things:
- make kswapd sleep just HZ, just like in 2.3
- don't start freeing memory from a user process when
we're at or just below the limit:
- we need the kernel lock so freeing memory
together with kswapd isn't possible anyway
- if kswapd can keep up, there's no latency
penalty for (kernel) memory allocations
- when we truly are low on memory or kswapd
can't keep up, then any __GFP_WAIT allocations
_will_ wait while trying to free memory
(so there's less chance of running out for
GFP_ATOMIC ones)
- wake up kswapd somewhat earlier (instead of too late)
This should be enough to make sure that 2.2.1* doesn't
run out of memory on a slight network flooding any more.
Note that I have only compiled the code with this patch
and not tried it, this wouldn't have worked anyway because
I can't create the problem situation (fast network, etc)
at home...
regards,
Rik
-- The Internet is not a network of computers. It is a network of people. That is its real strength.--- linux-2.2.15-pre3/mm/vmscan.c.orig Wed Jan 19 21:18:54 2000 +++ linux-2.2.15-pre3/mm/vmscan.c Wed Jan 19 22:06:34 2000 @@ -490,12 +490,13 @@ { if (do_try_to_free_pages(GFP_KSWAPD)) { + run_task_queue(&tq_disk); if (tsk->need_resched) schedule(); continue; } tsk->state = TASK_INTERRUPTIBLE; - schedule_timeout(10*HZ); + schedule_timeout(HZ); } } } @@ -509,18 +510,16 @@ * from user processes, because the locking issues are * nasty to the extreme (file write locks, and MM locking) * - * One option might be to let kswapd do all the page-out - * and VM page table scanning that needs locking, and this - * process thread could do just the mmap shrink stage that - * can be done by just dropping cached pages without having - * any deadlock issues. + * If we're on or just slighly below freepages.low, kswapd + * should manage on its own, we just give it a nudge. This + * should also reduce contention for the kernel lock above. */ int try_to_free_pages(unsigned int gfp_mask) { int retval = 1; wake_up_interruptible(&kswapd_wait); - if (gfp_mask & __GFP_WAIT) + if ((gfp_mask & __GFP_WAIT) && (nr_free_pages < (freepages.low - 4))) retval = do_try_to_free_pages(gfp_mask); return retval; } --- linux-2.2.15-pre3/mm/page_alloc.c.orig Wed Jan 19 21:32:05 2000 +++ linux-2.2.15-pre3/mm/page_alloc.c Wed Jan 19 21:42:00 2000 @@ -212,7 +212,7 @@ if (!(current->flags & PF_MEMALLOC)) { int freed; - if (nr_free_pages > freepages.min) { + if (nr_free_pages > freepages.low) { if (!low_on_memory) goto ok_to_allocate; if (nr_free_pages >= freepages.high) {
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sun Jan 23 2000 - 21:00:20 EST