At 2022-05-31 02:29:18, "Jakub Kicinski" <kuba@xxxxxxxxxx> wrote:
>On Mon, 30 May 2022 12:27:05 -0700 Jakub Kicinski wrote:
>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>> index e008a3df0485..360a545ee5e8 100644
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -5537,6 +5537,7 @@ EXPORT_SYMBOL(free_pages);
>> * sk_buff->head, or to be used in the "frags" portion of skb_shared_info.
>> */
>> static struct page *__page_frag_cache_refill(struct page_frag_cache *nc,
>> + unsigned int fragsz,
>> gfp_t gfp_mask)
>> {
>> struct page *page = NULL;
>> @@ -5549,7 +5550,7 @@ static struct page *__page_frag_cache_refill(struct page_frag_cache *nc,
>> PAGE_FRAG_CACHE_MAX_ORDER);
>> nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE;
>> #endif
>> - if (unlikely(!page))
>> + if (unlikely(!page && fragsz <= PAGE_SIZE))
>> page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);
>>
>> nc->va = page ? page_address(page) : NULL;
>> @@ -5576,7 +5577,7 @@ void *page_frag_alloc_align(struct page_frag_cache *nc,
>>
>> if (unlikely(!nc->va)) {
>> refill:
>> - page = __page_frag_cache_refill(nc, gfp_mask);
>> + page = __page_frag_cache_refill(nc, fragsz, gfp_mask);
>> if (!page)
>> return NULL;
>
>Oh, well, the reuse also needs an update. We can slap a similar
>condition next to the pfmemalloc check.
The sample code above cannot completely solve the current problem.
For example, when fragsz is greater than PAGE_FRAG_CACHE_MAX_SIZE(32768),
__page_frag_cache_refill will return a memory of only 32768 bytes, so
should we continue to expand the PAGE_FRAG_CACHE_MAX_SIZE? Maybe more
work needs to be done
