Re: 2.4.11pre4 swapping out all over the place

[Simon Kirby <sim@netnation.com>]

On Sat, Oct 06, 2001 at 02:59:04PM -0700, Linus Torvalds wrote:

> On Sat, 6 Oct 2001, Tobias Ringstrom wrote:
> >
> > Sure, replacing try_to_free_pages() in 2.4.11-pre4 with the one in
> > 2.4.11-pre3 solves the problem.
> 
> Ok, can you try this slightly more involved patch instead? It basically
> keeps the old try_to_free_pages() (it _looks_ different, but the logic is
> the same), but also should honour the OOM-killer.

Hmm...Was this supposed to apply against pre4?  The second hunk of
page_alloc.c fails for me, and I just tried again with a fresh tree.

Ah, it applied with patch -l.  Whitespace problems?

Simon-

> diff -u --recursive --new-file pre4/linux/mm/oom_kill.c linux/mm/oom_kill.c
> --- pre4/linux/mm/oom_kill.c	Thu Oct  4 19:52:11 2001
> +++ linux/mm/oom_kill.c	Fri Oct  5 13:13:43 2001
> @@ -241,13 +241,12 @@
>  		return 0;
> 
>  	/*
> -	 * If the buffer and page cache (excluding swap cache) are over
> +	 * If the buffer and page cache (including swap cache) are over
>  	 * their (/proc tunable) minimum, we're still not OOM.  We test
>  	 * this to make sure we don't return OOM when the system simply
>  	 * has a hard time with the cache.
>  	 */
>  	cache_mem = atomic_read(&page_cache_size);
> -	cache_mem -= swapper_space.nrpages;
>  	limit = 2;
>  	limit *= num_physpages / 100;
> 
> diff -u --recursive --new-file pre4/linux/mm/page_alloc.c linux/mm/page_alloc.c
> --- pre4/linux/mm/page_alloc.c	Thu Oct  4 19:52:11 2001
> +++ linux/mm/page_alloc.c	Sat Oct  6 14:54:59 2001
> @@ -357,6 +357,7 @@
> 
>  	/* here we're in the low on memory slow path */
> 
> +rebalance:
>  	if (current->flags & PF_MEMALLOC) {
>  		zone = zonelist->zones;
>  		for (;;) {
> @@ -371,48 +372,28 @@
>  		return NULL;
>  	}
> 
> - rebalance:
>  	page = balance_classzone(classzone, gfp_mask, order, &freed);
>  	if (page)
>  		return page;
> 
>  	zone = zonelist->zones;
> -	if (likely(freed)) {
> -		for (;;) {
> -			zone_t *z = *(zone++);
> -			if (!z)
> -				break;
> +	for (;;) {
> +		zone_t *z = *(zone++);
> +		if (!z)
> +			break;
> 
> -			if (zone_free_pages(z, order) > z->pages_min) {
> -				page = rmqueue(z, order);
> -				if (page)
> -					return page;
> -			}
> -		}
> -		goto rebalance;
> -	} else {
> -		/*
> -		 * Check that no other task is been killed meanwhile,
> -		 * in such a case we can succeed the allocation.
> -		 */
> -		for (;;) {
> -			zone_t *z = *(zone++);
> -			if (!z)
> -				break;
> -
> -			if (zone_free_pages(z, order) > z->pages_min) {
> -				page = rmqueue(z, order);
> -				if (page)
> -					return page;
> -			}
> +		if (zone_free_pages(z, order) > z->pages_min) {
> +			page = rmqueue(z, order);
> +			if (page)
> +				return page;
>  		}
> -
> -		goto rebalance;
>  	}
> 
> -	printk(KERN_NOTICE "__alloc_pages: %u-order allocation failed (gfp=0x%x/%i) from %p\n",
> -	       order, gfp_mask, !!(current->flags & PF_MEMALLOC), __builtin_return_address(0));
> -	return NULL;
> +	/* Yield for kswapd, and try again */
> +	current->policy |= SCHED_YIELD;
> +	__set_current_state(TASK_RUNNING);
> +	schedule();
> +	goto rebalance;
>  }
> 
>  /*
> diff -u --recursive --new-file pre4/linux/mm/vmscan.c linux/mm/vmscan.c
> --- pre4/linux/mm/vmscan.c	Thu Oct  4 19:52:11 2001
> +++ linux/mm/vmscan.c	Sat Oct  6 14:54:59 2001
> @@ -553,14 +556,16 @@
>  int try_to_free_pages(zone_t * classzone, unsigned int gfp_mask, unsigned int order)
>  {
>  	int ret = 0;
> +	int priority = DEF_PRIORITY;
>  	int nr_pages = SWAP_CLUSTER_MAX;
> 
> -	nr_pages = shrink_caches(DEF_PRIORITY, classzone, gfp_mask, nr_pages);
> +	do {
> +		nr_pages = shrink_caches(priority, classzone, gfp_mask, nr_pages);
> +		if (nr_pages <= 0)
> +			return 1;
> 
> -	if (nr_pages < SWAP_CLUSTER_MAX)
> -		ret |= 1;
> -
> -	ret |= swap_out(DEF_PRIORITY, classzone, gfp_mask, SWAP_CLUSTER_MAX << 2);
> +		ret |= swap_out(priority, classzone, gfp_mask, SWAP_CLUSTER_MAX << 2);
> +	} while (--priority);
> 
>  	return ret;
>  }
> 

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