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From: "Burakov, Anatoly" <anatoly.burakov@intel.com>
To: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
	David Marchand <david.marchand@redhat.com>,
	Yasufumi Ogawa <yasufum.o@gmail.com>
Cc: dev <dev@dpdk.org>, dpdk stable <stable@dpdk.org>,
	Yasufumi Ogawa <ogawa.yasufumi@lab.ntt.co.jp>
Subject: Re: [dpdk-stable] [PATCH v6 1/1] fbarray: fix duplicated fbarray file in secondary
Date: Wed, 6 Nov 2019 10:37:42 +0000
Message-ID: <9c3fba36-9cb2-76ad-198f-c11a63f01a9a@intel.com> (raw)
In-Reply-To: <2601191342CEEE43887BDE71AB97725801A8C800B7@IRSMSX104.ger.corp.intel.com>

On 05-Nov-19 11:41 AM, Ananyev, Konstantin wrote:
> 
> 
>> -----Original Message-----
>> From: Burakov, Anatoly <anatoly.burakov@intel.com>
>> Sent: Tuesday, November 5, 2019 11:31 AM
>> To: David Marchand <david.marchand@redhat.com>; Yasufumi Ogawa <yasufum.o@gmail.com>
>> Cc: Ananyev, Konstantin <konstantin.ananyev@intel.com>; dev <dev@dpdk.org>; dpdk stable <stable@dpdk.org>; Yasufumi Ogawa
>> <ogawa.yasufumi@lab.ntt.co.jp>
>> Subject: Re: [PATCH v6 1/1] fbarray: fix duplicated fbarray file in secondary
>>
>> On 05-Nov-19 10:13 AM, David Marchand wrote:
>>> Hello Anatoly, Yasufumi,
>>>
>>> On Mon, Nov 4, 2019 at 11:20 AM Burakov, Anatoly
>>> <anatoly.burakov@intel.com> wrote:
>>>>
>>>> On 01-Nov-19 9:04 AM, yasufum.o@gmail.com wrote:
>>>>> From: Yasufumi Ogawa <ogawa.yasufumi@lab.ntt.co.jp>
>>>>>
>>>>> In secondary_msl_create_walk(), it creates a file for fbarrays with its
>>>>> PID for reserving unique name among secondary processes. However, it
>>>>> does not work if several secondaries run as app containers because each
>>>>> of containerized secondary has PID 1, and failed to reserve unique name
>>>>> other than first one. To reserve unique name in each of containers, use
>>>>> hostname in addition to PID.
>>>>>
>>>>> Cc: stable@dpdk.org
>>>
>>> We can't backport this as is, see below.
>>>
>>>
>>>>>
>>>>> Signed-off-by: Yasufumi Ogawa <yasufum.o@gmail.com>
>>>>> ---
>>>>>     lib/librte_eal/common/include/rte_fbarray.h |  2 +-
>>>>>     lib/librte_eal/linux/eal/eal_memalloc.c     | 11 ++++++++---
>>>>>     2 files changed, 9 insertions(+), 4 deletions(-)
>>>>>
>>>>> diff --git a/lib/librte_eal/common/include/rte_fbarray.h b/lib/librte_eal/common/include/rte_fbarray.h
>>>>> index 6dccdbec9..5c2815093 100644
>>>>> --- a/lib/librte_eal/common/include/rte_fbarray.h
>>>>> +++ b/lib/librte_eal/common/include/rte_fbarray.h
>>>>> @@ -39,7 +39,7 @@ extern "C" {
>>>>>     #include <rte_compat.h>
>>>>>     #include <rte_rwlock.h>
>>>>>
>>>>> -#define RTE_FBARRAY_NAME_LEN 64
>>>>> +#define RTE_FBARRAY_NAME_LEN NAME_MAX
>>>
>>> The change on RTE_FBARRAY_NAME_LEN breaks the ABI, so we cannot
>>> backport this as is.
>>> For 19.11, we can allow this breakage, but we need an update of the
>>> release notes.
>>>
>>> Besides, what is the impact in terms of memory consumption?
>>>
>>>
>>>>>
>>>>>     struct rte_fbarray {
>>>>>         char name[RTE_FBARRAY_NAME_LEN]; /**< name associated with an array */
>>>>> diff --git a/lib/librte_eal/linux/eal/eal_memalloc.c b/lib/librte_eal/linux/eal/eal_memalloc.c
>>>>> index af6d0d023..24f0275c9 100644
>>>>> --- a/lib/librte_eal/linux/eal/eal_memalloc.c
>>>>> +++ b/lib/librte_eal/linux/eal/eal_memalloc.c
>>>>> @@ -1365,6 +1365,7 @@ secondary_msl_create_walk(const struct rte_memseg_list *msl,
>>>>>         struct rte_memseg_list *primary_msl, *local_msl;
>>>>>         char name[PATH_MAX];
>>>>>         int msl_idx, ret;
>>>>> +     char hostname[HOST_NAME_MAX] = { 0 };
>>>>>
>>>>>         if (msl->external)
>>>>>                 return 0;
>>>>> @@ -1373,9 +1374,13 @@ secondary_msl_create_walk(const struct rte_memseg_list *msl,
>>>>>         primary_msl = &mcfg->memsegs[msl_idx];
>>>>>         local_msl = &local_memsegs[msl_idx];
>>>>>
>>>>> -     /* create distinct fbarrays for each secondary */
>>>>> -     snprintf(name, RTE_FBARRAY_NAME_LEN, "%s_%i",
>>>>> -             primary_msl->memseg_arr.name, getpid());
>>>>> +     /* Create distinct fbarrays for each secondary by using PID and
>>>>> +      * hostname. The reason why using hostname is because PID could be
>>>>> +      * duplicated among secondaries if it is launched in a container.
>>>>> +      */
>>>>> +     gethostname(hostname, HOST_NAME_MAX);
>>>
>>> Personal preference, s/HOST_NAME_MAX/sizeof(hostname)/.
>>>
>>>
>>> hostname[] is HOST_NAME_MAX bytes long.
>>> In the worst case, we can get a non NULL terminated hostname string.
>>> "
>>>          gethostname() returns the null-terminated hostname in the
>>> character array name, which has a length of len bytes.  If the
>>> null-terminated hostname is too large to fit, then the name is
>>> truncated, and
>>>          no error is returned (but see NOTES below).  POSIX.1-2001 says
>>> that if such truncation occurs, then it is unspecified whether the
>>> returned buffer includes a terminating null byte.
>>> ...
>>> NOTES
>>>          SUSv2 guarantees that "Host names are limited to 255 bytes".
>>> POSIX.1-2001 guarantees that "Host names (not including the
>>> terminating null byte) are  limited  to  HOST_NAME_MAX  bytes".   On
>>> Linux,
>>>          HOST_NAME_MAX is defined with the value 64, which has been the
>>> limit since Linux 1.0 (earlier kernels imposed a limit of 8 bytes).
>>> "
>>>
>>> How about making hostname[] HOST_NAME_MAX+1 bytes long?
>>>
>>>>> +     snprintf(name, RTE_FBARRAY_NAME_LEN, "%s_%s_%d",
>>>>> +                     primary_msl->memseg_arr.name, hostname, (int)getpid());
>>>>>
>>>>>         ret = rte_fbarray_init(&local_msl->memseg_arr, name,
>>>>>                 primary_msl->memseg_arr.len,
>>>>>
>>>>
>>>> I think the order should be reversed. Both containers and non-containers
>>>> can have their hostname set, and RTE_FBARRAY_NAME_LEN is of fairly
>>>> limited length, so if the hostname is long enough, the PID never gets
>>>> into the name string, resulting in duplicates. It is better have pid first.
>>>
>>> Anatoly,
>>>
>>> On the principle, it seems better, yes.
>>> Just the comment on RTE_FBARRAY_NAME_LEN indicates that you missed the
>>> change at the top of the patch.
>>> What do you think of this change?
>>>
>>
>> Yes, i did miss that, apologies.
>>
>> I don't have a strong opinion on this change, however the above comment
>> would still be true if we make fbarray size to be hostname_max + 1 - we
>> still potentially get no space for a pid. So if we're going to have pid
>> in there as well, it should be hostname_max + pid_max (5 digits?) +
>> whatever underscores we have + null terminator, to ensure it fits under
>> any and all circumstances.#
> 
> I think that at least on linux we have more than enough space here:
> 
> $ find /usr/include -type f | xargs grep ' NAME_MAX' | grep define
> /usr/include/linux/limits.h:#define NAME_MAX         255        /* # chars in a file name */
> 
> $ find /usr/include -type f | xargs grep ' HOST_NAME_MAX' | grep define
> /usr/include/i386-linux-gnu/bits/local_lim.h:#define HOST_NAME_MAX             64
> /usr/include/x86_64-linux-gnu/bits/local_lim.h:#define HOST_NAME_MAX           64
> 

Okay, works for me :)

-- 
Thanks,
Anatoly

  reply index

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-16  1:59 [dpdk-stable] [PATCH] fbarray: get fbarrays from containerized secondary ogawa.yasufumi
2019-04-16  3:43 ` [dpdk-stable] [PATCH v2 0/1] Get " ogawa.yasufumi
2019-04-16  3:43   ` [dpdk-stable] [PATCH v2 1/1] fbarray: get " ogawa.yasufumi
2019-07-04 20:17     ` [dpdk-stable] [dpdk-dev] " Thomas Monjalon
2019-07-05  8:53     ` [dpdk-stable] " Burakov, Anatoly
2019-07-09 10:22       ` [dpdk-stable] [dpdk-dev] " Yasufumi Ogawa
2019-07-09 10:24         ` Burakov, Anatoly
2019-07-09 10:26           ` Burakov, Anatoly
2019-07-11  9:37             ` Yasufumi Ogawa
2019-07-11  9:43               ` Burakov, Anatoly
2019-07-11 10:31 ` [dpdk-stable] [PATCH v3 0/1] " yasufum.o
2019-07-11 10:31   ` [dpdk-stable] [PATCH v3 1/1] " yasufum.o
2019-07-11 10:53     ` Burakov, Anatoly
2019-07-11 11:57       ` Yasufumi Ogawa
2019-07-11 13:14         ` Burakov, Anatoly
2019-07-12  2:22           ` Yasufumi Ogawa
2019-07-22  1:06             ` Ogawa Yasufumi
2019-07-22  9:33               ` Burakov, Anatoly
2019-07-22  9:25             ` Burakov, Anatoly
2019-07-24  8:20   ` [dpdk-stable] [PATCH v4 0/1] " yasufum.o
2019-07-24  8:20     ` [dpdk-stable] [PATCH v4 1/1] " yasufum.o
2019-07-24  9:59       ` Burakov, Anatoly
2019-07-30  8:16         ` Thomas Monjalon
2019-07-30  9:18           ` Burakov, Anatoly
2019-07-31  5:48             ` Yasufumi Ogawa
2019-10-11  9:36       ` David Marchand
2019-10-25 15:36         ` David Marchand
2019-10-25 19:54           ` Yasufumi Ogawa
2019-10-26 16:15             ` David Marchand
2019-10-26 18:11               ` Yasufumi Ogawa
2019-10-28  8:07     ` [dpdk-stable] [PATCH v5 0/1] fbarray: fix duplicated fbarray file in secondary yasufum.o
2019-10-28  8:07       ` [dpdk-stable] [PATCH v5 1/1] " yasufum.o
2019-10-29 12:03         ` [dpdk-stable] [dpdk-dev] " Ananyev, Konstantin
2019-10-30 13:42           ` Yasufumi Ogawa
2019-10-30 19:00             ` Ananyev, Konstantin
2019-10-31 10:03               ` Yasufumi Ogawa
2019-10-31 10:32                 ` Ananyev, Konstantin
2019-11-01  9:04     ` [dpdk-stable] [PATCH v6 0/1] " yasufum.o
2019-11-01  9:04       ` [dpdk-stable] [PATCH v6 1/1] " yasufum.o
2019-11-01 12:01         ` Ananyev, Konstantin
2019-11-04 10:20         ` Burakov, Anatoly
2019-11-05 10:13           ` David Marchand
2019-11-05 11:31             ` Burakov, Anatoly
2019-11-05 11:41               ` Ananyev, Konstantin
2019-11-06 10:37                 ` Burakov, Anatoly [this message]
2019-11-08  3:19                   ` Yasufumi Ogawa
2019-11-13 21:43     ` [dpdk-stable] [PATCH v7 0/1] " yasufum.o
2019-11-13 21:43       ` [dpdk-stable] [PATCH v7 1/1] " yasufum.o
2019-11-14 10:01         ` Burakov, Anatoly
2019-11-14 11:42           ` Yasufumi Ogawa
2019-11-14 12:27             ` David Marchand
2019-11-26 19:40               ` Yasufumi Ogawa
2019-11-27 10:26                 ` Burakov, Anatoly
2019-11-14 12:55         ` David Marchand
2019-11-14 17:32         ` Ananyev, Konstantin

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