From mboxrd@z Thu Jan 1 00:00:00 1970
Return-Path: <anatoly.burakov@intel.com>
Received: from mga09.intel.com (mga09.intel.com [134.134.136.24])
by dpdk.org (Postfix) with ESMTP id 1EE381559;
Fri, 7 Sep 2018 14:24:10 +0200 (CEST)
X-Amp-Result: SKIPPED(no attachment in message)
X-Amp-File-Uploaded: False
Received: from fmsmga007.fm.intel.com ([10.253.24.52])
by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384;
07 Sep 2018 05:24:10 -0700
X-ExtLoop1: 1
X-IronPort-AV: E=Sophos;i="5.53,342,1531810800"; d="scan'208";a="68293894"
Received: from aburakov-mobl1.ger.corp.intel.com (HELO [10.237.220.152])
([10.237.220.152])
by fmsmga007.fm.intel.com with ESMTP; 07 Sep 2018 05:24:06 -0700
To: Tiwei Bie <tiwei.bie@intel.com>
Cc: maxime.coquelin@redhat.com, zhihong.wang@intel.com, dev@dpdk.org,
seanbh@gmail.com, stable@dpdk.org
References: <20180905042852.6212-1-tiwei.bie@intel.com>
<20180905042852.6212-4-tiwei.bie@intel.com>
<a82e230d-7fd7-ade0-d7a9-18265f30b00b@intel.com>
<20180907113744.GA22511@debian>
From: "Burakov, Anatoly" <anatoly.burakov@intel.com>
Message-ID: <c2ae9cea-b546-8dd2-68ba-e4a4e1038ef0@intel.com>
Date: Fri, 7 Sep 2018 13:24:05 +0100
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101
Thunderbird/52.9.1
MIME-Version: 1.0
In-Reply-To: <20180907113744.GA22511@debian>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Subject: Re: [dpdk-dev] [PATCH 3/3] net/virtio-user: fix memory hotplug
support in vhost-kernel
X-BeenThere: dev@dpdk.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <https://mails.dpdk.org/options/dev>,
<mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://mails.dpdk.org/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <https://mails.dpdk.org/listinfo/dev>,
<mailto:dev-request@dpdk.org?subject=subscribe>
X-List-Received-Date: Fri, 07 Sep 2018 12:24:11 -0000
On 07-Sep-18 12:37 PM, Tiwei Bie wrote:
> On Fri, Sep 07, 2018 at 10:44:22AM +0100, Burakov, Anatoly wrote:
>> On 05-Sep-18 5:28 AM, Tiwei Bie wrote:
>>> It's possible to have much more hugepage backed memory regions
>>> than what vhost-kernel supports due to the memory hotplug, which
>>> may cause problems. A better solution is to have the virtio-user
>>> pass all the memory ranges reserved by DPDK to vhost-kernel.
>>>
>>> Fixes: 12ecb2f63b12 ("net/virtio-user: support memory hotplug")
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
>>> ---
>>> drivers/net/virtio/virtio_user/vhost_kernel.c | 38 +++++++++----------
>>> 1 file changed, 18 insertions(+), 20 deletions(-)
>>>
>>> diff --git a/drivers/net/virtio/virtio_user/vhost_kernel.c b/drivers/net/virtio/virtio_user/vhost_kernel.c
>>> index 897fee0af..9338166d9 100644
>>> --- a/drivers/net/virtio/virtio_user/vhost_kernel.c
>>> +++ b/drivers/net/virtio/virtio_user/vhost_kernel.c
>>> @@ -70,41 +70,41 @@ static uint64_t vhost_req_user_to_kernel[] = {
>>> [VHOST_USER_SET_MEM_TABLE] = VHOST_SET_MEM_TABLE,
>>> };
>>> -struct walk_arg {
>>> - struct vhost_memory_kernel *vm;
>>> - uint32_t region_nr;
>>> -};
>>> static int
>>> -add_memory_region(const struct rte_memseg_list *msl __rte_unused,
>>> - const struct rte_memseg *ms, size_t len, void *arg)
>>> +add_memseg_list(const struct rte_memseg_list *msl, void *arg)
>>> {
>>> - struct walk_arg *wa = arg;
>>> + struct vhost_memory_kernel *vm = arg;
>>> struct vhost_memory_region *mr;
>>> void *start_addr;
>>> + uint64_t len;
>>> - if (wa->region_nr >= max_regions)
>>> + if (vm->nregions >= max_regions)
>>> return -1;
>>> - mr = &wa->vm->regions[wa->region_nr++];
>>> - start_addr = ms->addr;
>>> + start_addr = msl->base_va;
>>> + len = msl->page_sz * msl->memseg_arr.len;
>>> +
>>> + mr = &vm->regions[vm->nregions++];
>>> mr->guest_phys_addr = (uint64_t)(uintptr_t)start_addr;
>>> mr->userspace_addr = (uint64_t)(uintptr_t)start_addr;
>>> mr->memory_size = len;
>>> - mr->mmap_offset = 0;
>>> + mr->mmap_offset = 0; /* flags_padding */
>>> +
>>> + PMD_DRV_LOG(DEBUG, "index=%u addr=%p len=%" PRIu64,
>>> + vm->nregions - 1, start_addr, len);
>>> return 0;
>>> }
>>> -/* By default, vhost kernel module allows 64 regions, but DPDK allows
>>> - * 256 segments. As a relief, below function merges those virtually
>>> - * adjacent memsegs into one region.
>>> +/* By default, vhost kernel module allows 64 regions, but DPDK may
>>> + * have much more memory regions. Below function will treat each
>>> + * contiguous memory space reserved by DPDK as one region.
>>> */
>>> static struct vhost_memory_kernel *
>>> prepare_vhost_memory_kernel(void)
>>> {
>>> struct vhost_memory_kernel *vm;
>>> - struct walk_arg wa;
>>> vm = malloc(sizeof(struct vhost_memory_kernel) +
>>> max_regions *
>>> @@ -112,20 +112,18 @@ prepare_vhost_memory_kernel(void)
>>> if (!vm)
>>> return NULL;
>>> - wa.region_nr = 0;
>>> - wa.vm = vm;
>>> + vm->nregions = 0;
>>> + vm->padding = 0;
>>> /*
>>> * The memory lock has already been taken by memory subsystem
>>> * or virtio_user_start_device().
>>> */
>>> - if (rte_memseg_contig_walk_thread_unsafe(add_memory_region, &wa) < 0) {
>>> + if (rte_memseg_list_walk_thread_unsafe(add_memseg_list, vm) < 0) {
>>> free(vm);
>>> return NULL;
>>> }
>>> - vm->nregions = wa.region_nr;
>>> - vm->padding = 0;
>>> return vm;
>>> }
>>>
>>
>> Doesn't that assume single file segments mode?
>
> This is to find out the VA ranges reserved by memory subsystem.
> Why does it need to assume single file segments mode?
If you are not in single-file segments mode, each individual page in a
VA-contiguous area will be behind a different fd - so it will be part of
a different region, would it not?
>
>
>>
>> --
>> Thanks,
>> Anatoly
>
--
Thanks,
Anatoly