Re: Linux 4.9-rc6

[Thorsten Leemhuis]

Lo! On 21.11.2016 14:51, Eric Dumazet wrote:
> On Mon, 2016-11-21 at 05:32 -0800, Eric Dumazet wrote:
>> Oh, this was definitely my intent of course, thanks for noticing this
>> typo ;)
> V2 is fixing this, and brings back NUMA spreading,
> (eg alloc_large_system_hash() done at boot time )

What the status of below patch? From the discussion it looks a lot like
it was developed to fix a regression in 4.9, but the patch afaics has
neither his mainline or linux-next yet. That's why I'm inclined to add
it to this weeks regression report.

Ciao, Thorsten

> lpaa24:~# grep alloc_large /proc/vmallocinfo 
> 0xffffc90000009000-0xffffc9000000c000   12288 alloc_large_system_hash+0x178/0x238 pages=2 vmalloc N0=1 N1=1
> 0xffffc9000000c000-0xffffc9000000f000   12288 alloc_large_system_hash+0x178/0x238 pages=2 vmalloc N0=1 N1=1
> 0xffffc9000001e000-0xffffc9000009f000  528384 alloc_large_system_hash+0x178/0x238 pages=128 vmalloc N0=64 N1=64
> 0xffffc9000009f000-0xffffc900000e0000  266240 alloc_large_system_hash+0x178/0x238 pages=64 vmalloc N0=32 N1=32
> 0xffffc900001d3000-0xffffc900101d4000 268439552 alloc_large_system_hash+0x178/0x238 pages=65536 vmalloc vpages N0=32768 N1=32768
> 0xffffc900101d4000-0xffffc900181d5000 134221824 alloc_large_system_hash+0x178/0x238 pages=32768 vmalloc vpages N0=16384 N1=16384
> 0xffffc900181d5000-0xffffc900185d6000 4198400 alloc_large_system_hash+0x178/0x238 pages=1024 vmalloc vpages N0=512 N1=512
> 0xffffc900185d6000-0xffffc900189d7000 4198400 alloc_large_system_hash+0x178/0x238 pages=1024 vmalloc vpages N0=512 N1=512
> 0xffffc9001b271000-0xffffc9001b672000 4198400 alloc_large_system_hash+0x178/0x238 pages=1024 vmalloc vpages N0=512 N1=512
> 0xffffc9001b672000-0xffffc9001b675000   12288 alloc_large_system_hash+0x178/0x238 pages=2 vmalloc N0=1 N1=1
> 0xffffc9001b675000-0xffffc9001b776000 1052672 alloc_large_system_hash+0x178/0x238 pages=256 vmalloc N0=128 N1=128
> 0xffffc9001b776000-0xffffc9001b977000 2101248 alloc_large_system_hash+0x178/0x238 pages=512 vmalloc N0=256 N1=256
> 0xffffc9001b977000-0xffffc9001bb78000 2101248 alloc_large_system_hash+0x178/0x238 pages=512 vmalloc N0=256 N1=256
> 0xffffc9001c075000-0xffffc9001c176000 1052672 alloc_large_system_hash+0x178/0x238 pages=256 vmalloc N0=128 N1=128
> 
> 
>  mm/vmalloc.c |   47 +++++++++++++++++++++++++++++++++++++++--------
>  1 file changed, 39 insertions(+), 8 deletions(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index f2481cb4e6b2..f4b9c9238f86 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -21,6 +21,7 @@
>  #include <linux/debugobjects.h>
>  #include <linux/kallsyms.h>
>  #include <linux/list.h>
> +#include <linux/mempolicy.h>
>  #include <linux/notifier.h>
>  #include <linux/rbtree.h>
>  #include <linux/radix-tree.h>
> @@ -1602,9 +1603,11 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
>  				 pgprot_t prot, int node)
>  {
>  	struct page **pages;
> -	unsigned int nr_pages, array_size, i;
> +	unsigned int nr_pages, array_size, i, j;
>  	const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
>  	const gfp_t alloc_mask = gfp_mask | __GFP_NOWARN;
> +	const gfp_t multi_alloc_mask = (alloc_mask & ~__GFP_DIRECT_RECLAIM) | __GFP_NORETRY;
> +	int max_node_order = MAX_ORDER - 1;
>  
>  	nr_pages = get_vm_area_size(area) >> PAGE_SHIFT;
>  	array_size = (nr_pages * sizeof(struct page *));
> @@ -1624,20 +1627,48 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
>  		return NULL;
>  	}
>  
> -	for (i = 0; i < area->nr_pages; i++) {
> -		struct page *page;
> +	if (IS_ENABLED(CONFIG_NUMA) && nr_online_nodes > 1) {
> +		struct mempolicy *policy = current->mempolicy;
> +		int pages_per_node;
>  
> -		if (node == NUMA_NO_NODE)
> -			page = alloc_page(alloc_mask);
> -		else
> -			page = alloc_pages_node(node, alloc_mask, 0);
> +		if (policy && policy->mode == MPOL_INTERLEAVE) {
> +			pages_per_node = DIV_ROUND_UP(nr_pages,
> +						      nr_online_nodes);
> +			max_node_order = min(max_node_order,
> +					     ilog2(pages_per_node));
> +		}
> +	}
> +
> +	for (i = 0; i < area->nr_pages;) {
> +		unsigned int chunk_order = min(ilog2(area->nr_pages - i),
> +					       max_node_order);
> +		struct page *page = NULL;
> +
> +		while (chunk_order) {
> +			if (node == NUMA_NO_NODE)
> +				page = alloc_pages(multi_alloc_mask, chunk_order);
> +			else
> +				page = alloc_pages_node(node, multi_alloc_mask, chunk_order);
> +			if (page) {
> +				split_page(page, chunk_order);
> +				break;
> +			}
> +			chunk_order--;
> +		}
> +		if (!page) {
> +			if (node == NUMA_NO_NODE)
> +				page = alloc_pages(alloc_mask, 0);
> +			else
> +				page = alloc_pages_node(node, alloc_mask, 0);
> +		}
>  
>  		if (unlikely(!page)) {
>  			/* Successfully allocated i pages, free them in __vunmap() */
>  			area->nr_pages = i;
>  			goto fail;
>  		}
> -		area->pages[i] = page;
> +		for (j = 0; j < (1U << chunk_order); j++)
> +			area->pages[i++] = page++;
>  		if (gfpflags_allow_blocking(gfp_mask))
>  			cond_resched();
>  	}
> 
>