Re: [PATCH] ion: Consider ion pool pages as indirectly reclaimable

[Laura Abbott]

On 04/24/2018 08:43 PM, vjitta@xxxxxxxxxxxxxx wrote:
> From: Vijayanand Jitta <vjitta@xxxxxxxxxxxxxx>
>
> An issue is observed where mallocs are failing due to overcommit failure.
> The failure happens when there is high ION page pool since ION page
> pool is not considered reclaimable by the overcommit calculation code.
> This change considers ion pool pages as indirectly reclaimable and thus
> accounted as available memory in the overcommit calculation.
>
> Signed-off-by: Vijayanand Jitta <vjitta@xxxxxxxxxxxxxx>
> ---
>   drivers/staging/android/ion/ion_page_pool.c | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/drivers/staging/android/ion/ion_page_pool.c b/drivers/staging/android/ion/ion_page_pool.c
> index db8f614..9bc56eb 100644
> --- a/drivers/staging/android/ion/ion_page_pool.c
> +++ b/drivers/staging/android/ion/ion_page_pool.c
> @@ -32,6 +32,9 @@ static void ion_page_pool_add(struct ion_page_pool *pool, struct page *page)
>   		list_add_tail(&page->lru, &pool->low_items);
>   		pool->low_count++;
>   	}
> +
> +	mod_node_page_state(page_pgdat(page), NR_INDIRECTLY_RECLAIMABLE_BYTES,
> +			    (1 << (PAGE_SHIFT + pool->order)));
>   	mutex_unlock(&pool->mutex);
>   }
>   
> @@ -50,6 +53,8 @@ static struct page *ion_page_pool_remove(struct ion_page_pool *pool, bool high)
>   	}
>   
>   	list_del(&page->lru);
> +	mod_node_page_state(page_pgdat(page), NR_INDIRECTLY_RECLAIMABLE_BYTES,
> +			    -(1 << (PAGE_SHIFT + pool->order)));
>   	return page;
>   }
>   

I'm sure this fixes the problem but I don't think we want to
start throwing page adjustments into Ion. Why isn't this
memory already considered reclaimable by existing calculations?

Thanks,
Laura