From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: "Burakov, Anatoly" <anatoly.burakov@intel.com>,
Jianfeng Tan <jianfeng.tan@intel.com>,
dev@dpdk.org
Cc: tiwei.bie@intel.com, zhiyong.yang@intel.com
Subject: Re: [dpdk-dev] [PATCH] net/virtio-user: fix hugepage files enumeration
Date: Fri, 4 May 2018 09:40:03 +0200 [thread overview]
Message-ID: <968eaf20-b450-c047-782e-d417c78e732b@redhat.com> (raw)
In-Reply-To: <93064ddf-b753-4d3e-2992-4fb94e984b36@intel.com>
Hi Anatoly,
On 04/27/2018 11:31 AM, Burakov, Anatoly wrote:
> On 26-Apr-18 4:34 PM, Jianfeng Tan wrote:
>> After the commit 2a04139f66b4 ("eal: add single file segments option"),
>> one hugepage file could contain multiple hugepages which are further
>> mapped to different memory regions.
>>
>> Original enumeration implementation cannot handle this situation.
>>
>> This patch filters out the duplicated files; and adjust the size after
>> the enumeration.
>>
>> Fixes: 6a84c37e3975 ("net/virtio-user: add vhost-user adapter layer")
>>
>> Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>
>> ---
>> .../howto/virtio_user_for_container_networking.rst | 3 ++-
>> drivers/net/virtio/virtio_user/vhost_user.c | 28
>> ++++++++++++++++++++--
>> 2 files changed, 28 insertions(+), 3 deletions(-)
>>
>> diff --git a/doc/guides/howto/virtio_user_for_container_networking.rst
>> b/doc/guides/howto/virtio_user_for_container_networking.rst
>> index aa68b53..476ce3a 100644
>> --- a/doc/guides/howto/virtio_user_for_container_networking.rst
>> +++ b/doc/guides/howto/virtio_user_for_container_networking.rst
>> @@ -109,7 +109,8 @@ We have below limitations in this solution:
>> * Cannot work with --no-huge option. Currently, DPDK uses anonymous
>> mapping
>> under this option which cannot be reopened to share with vhost
>> backend.
>> * Cannot work when there are more than VHOST_MEMORY_MAX_NREGIONS(8)
>> hugepages.
>> - In another word, do not use 2MB hugepage so far.
>> + If you have more regions (especially when 2MB hugepages are used),
>> the option,
>> + --single-file-segments, can help to reduce the number of shared
>> files.
>> * Applications should not use file name like HUGEFILE_FMT
>> ("%smap_%d"). That
>> will bring confusion when sharing hugepage files with backend by
>> name.
>> * Root privilege is a must. DPDK resolves physical addresses of
>> hugepages
>> diff --git a/drivers/net/virtio/virtio_user/vhost_user.c
>> b/drivers/net/virtio/virtio_user/vhost_user.c
>> index a6df97a..01201c9 100644
>> --- a/drivers/net/virtio/virtio_user/vhost_user.c
>> +++ b/drivers/net/virtio/virtio_user/vhost_user.c
>> @@ -138,12 +138,13 @@ struct hugepage_file_info {
>> static int
>> get_hugepage_file_info(struct hugepage_file_info huges[], int max)
>> {
>> - int idx;
>> + int idx, k, exist;
>> FILE *f;
>> char buf[BUFSIZ], *tmp, *tail;
>> char *str_underline, *str_start;
>> int huge_index;
>> uint64_t v_start, v_end;
>> + struct stat stats;
>> f = fopen("/proc/self/maps", "r");
>> if (!f) {
>> @@ -183,16 +184,39 @@ get_hugepage_file_info(struct hugepage_file_info
>> huges[], int max)
>> if (sscanf(str_start, "map_%d", &huge_index) != 1)
>> continue;
>> + /* skip duplicated file which is mapped to different regions */
>> + for (k = 0, exist = -1; k < idx; ++k) {
>> + if (!strcmp(huges[k].path, tmp)) {
>> + exist = k;
>> + break;
>> + }
>> + }
>> + if (exist >= 0)
>> + continue;
>> +
>> if (idx >= max) {
>> PMD_DRV_LOG(ERR, "Exceed maximum of %d", max);
>> goto error;
>> }
>> +
>> huges[idx].addr = v_start;
>> - huges[idx].size = v_end - v_start;
>> + huges[idx].size = v_end - v_start; /* To be corrected later */
>> snprintf(huges[idx].path, PATH_MAX, "%s", tmp);
>> idx++;
>> }
>> + /* correct the size for files who have many regions */
>> + for (k = 0; k < idx; ++k) {
>> + if (stat(huges[k].path, &stats) < 0) {
>> + PMD_DRV_LOG(ERR, "Failed to stat %s, %s\n",
>> + huges[k].path, strerror(errno));
>> + continue;
>> + }
>> + huges[k].size = stats.st_size;
>> + PMD_DRV_LOG(INFO, "file %s, size %"PRIx64"\n",
>> + huges[k].path, huges[k].size);
>> + }
>> +
>> fclose(f);
>> return idx;
>>
>
> That sounds like potentially a lot of strcmp()'s (quadratic?). Can't it
> be sped up somehow? Maybe use rte_hash for storing this data?
>
This patch is required to have virtio-user to work with 2MB pages.
While it may be improved later, I think we should pick it for v18.05.
Is it fine for you?
Thanks,
Maxime
next prev parent reply other threads:[~2018-05-04 7:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-26 15:34 Jianfeng Tan
2018-04-27 9:31 ` Burakov, Anatoly
2018-05-04 7:40 ` Maxime Coquelin [this message]
2018-05-04 7:52 ` Burakov, Anatoly
2018-05-04 14:16 ` Maxime Coquelin
2018-05-04 15:09 ` Maxime Coquelin
2018-05-08 14:26 ` Ferruh Yigit
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