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Subject: Re: [PATCH] ion: Consider ion pool pages as indirectly reclaimable
To:     vjitta@codeaurora.org, sumit.semwal@linaro.org
Cc:     gregkh@linuxfoundation.org, arve@android.com, tkjos@android.com,
        maco@android.com, devel@driverdev.osuosl.org,
        linux-kernel@vger.kernel.org
References: <1524627830-17187-1-git-send-email-vjitta@codeaurora.org>
From:   Laura Abbott <labbott@redhat.com>
Message-ID: <8618859b-06f9-39a7-80a9-af36cf9faf9f@redhat.com>
Date:   Wed, 25 Apr 2018 08:47:34 -0700
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On 04/24/2018 08:43 PM, vjitta@codeaurora.org wrote:
> From: Vijayanand Jitta <vjitta@codeaurora.org>
> 
> 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@codeaurora.org>
> ---
>   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