Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII;
 format=flowed
Content-Transfer-Encoding: 7bit
Date:   Fri, 27 Apr 2018 10:40:36 +0530
From:   vjitta@codeaurora.org
To:     Laura Abbott <labbott@redhat.com>
Cc:     sumit.semwal@linaro.org, gregkh@linuxfoundation.org,
        arve@android.com, tkjos@android.com, maco@android.com,
        devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org,
        linux-kernel-owner@vger.kernel.org
Subject: Re: [PATCH] ion: Consider ion pool pages as indirectly reclaimable
In-Reply-To: <8618859b-06f9-39a7-80a9-af36cf9faf9f@redhat.com>
References: <1524627830-17187-1-git-send-email-vjitta@codeaurora.org>
 <8618859b-06f9-39a7-80a9-af36cf9faf9f@redhat.com>
Message-ID: <fb3f0974e9e83b33e7eac267aeecf130@codeaurora.org>
User-Agent: Roundcube Webmail/1.2.5
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 2018-04-25 21:17, Laura Abbott wrote:
> 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

You can refer to discussion here https://lkml.org/lkml/2018/3/5/361 
introducing
NR_INDIRECTLY_RECLAIMABLE_BYTES for the memory which is not currently 
considered
as reclaimable

Thanks,
Vijay