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;
Subject: Re: [RFC PATCH 0/5] kmalloc-reclaimable caches
To:     Vlastimil Babka <vbabka@suse.cz>, Roman Gushchin <guro@fb.com>
Cc:     linux-mm@kvack.org, Michal Hocko <mhocko@kernel.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
        Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Vijayanand Jitta <vjitta@codeaurora.org>
References: <20180524110011.1940-1-vbabka@suse.cz>
 <20180524121347.GA10763@castle.DHCP.thefacebook.com>
 <fea26519-2b5f-b404-872d-47afabcd3393@suse.cz>
From:   Laura Abbott <labbott@redhat.com>
Message-ID: <01cbee1d-e5cf-8de1-6610-3043a2c5d5ca@redhat.com>
Date:   Thu, 24 May 2018 10:35:03 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.7.0
MIME-Version: 1.0
In-Reply-To: <fea26519-2b5f-b404-872d-47afabcd3393@suse.cz>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 05/24/2018 08:52 AM, Vlastimil Babka wrote:
> On 05/24/2018 02:13 PM, Roman Gushchin wrote:
>> On Thu, May 24, 2018 at 01:00:06PM +0200, Vlastimil Babka wrote:
>>> Hi,
>>>
>>> - I haven't find any other obvious users for reclaimable kmalloc (yet)
>>
>> As I remember, ION memory allocator was discussed related to this theme:
>> https://lkml.org/lkml/2018/4/24/1288
> 
> +CC Laura
> 
> Yeah ION added the NR_INDIRECTLY_RECLAIMABLE_BYTES handling, which is
> adjusted to page granularity in patch 4. I'm not sure if it should use
> kmalloc as it seems to be allocating order-X pages, where kmalloc/slab
> just means extra overhead. But maybe if it doesn't allocate/free too
> frequently, it could work?
> 

The page pool allocation is supposed to be a slow path but it's
one I'd rather not have too much overhead. It also just looks really odd
to be allocating higher order pages via kmalloc imho.
  
>>> I did a superset as IIRC somebody suggested that in the older threads or at LSF.
>>
>> This looks nice to me!
>>
>> Thanks!
>>
>