DPDK patches and discussions
 help / color / Atom feed
From: "Burakov, Anatoly" <anatoly.burakov@intel.com>
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: [dpdk-dev] [PATCH v6 1/1] fbarray: fix duplicated fbarray file in secondary
Date: Tue, 5 Nov 2019 11:31:28 +0000
Message-ID: <d7a0729c-eb4d-d87a-4f7a-0d94627010e4@intel.com> (raw)
In-Reply-To: <CAJFAV8xPPu8kDNcjUycvWKjUBc3YuOT_ZQ_aDjrD4-yW3JgiEg@mail.gmail.com>

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.

Wrt memory usage, honestly, we don't live in a "640K should be enough 
for everyone" era any more. I don't see this being a major issue. This 
is not a hotpath, and we reserve half a terabyte of virtual memory at 
startup as it is. A few kilo/megabytes more isn't going to make much of 
a difference here.

-- 
Thanks,
Anatoly

  reply index

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-16  1:59 [dpdk-dev] [PATCH] fbarray: get fbarrays from containerized secondary ogawa.yasufumi
2019-04-16  1:59 ` ogawa.yasufumi
2019-04-16  3:43 ` [dpdk-dev] [PATCH v2 0/1] Get " ogawa.yasufumi
2019-04-16  3:43   ` ogawa.yasufumi
2019-04-16  3:43   ` [dpdk-dev] [PATCH v2 1/1] fbarray: get " ogawa.yasufumi
2019-04-16  3:43     ` ogawa.yasufumi
2019-07-04 20:17     ` Thomas Monjalon
2019-07-05  8:53     ` Burakov, Anatoly
2019-07-09 10:22       ` 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-dev] [PATCH v3 0/1] " yasufum.o
2019-07-11 10:31   ` [dpdk-dev] [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-dev] [PATCH v4 0/1] " yasufum.o
2019-07-24  8:20     ` [dpdk-dev] [PATCH v4 1/1] " yasufum.o
2019-07-24  9:59       ` Burakov, Anatoly
2019-07-30  8:16         ` [dpdk-dev] [dpdk-stable] " Thomas Monjalon
2019-07-30  9:18           ` Burakov, Anatoly
2019-07-31  5:48             ` Yasufumi Ogawa
2019-10-11  9:36       ` [dpdk-dev] " 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-dev] [PATCH v5 0/1] fbarray: fix duplicated fbarray file in secondary yasufum.o
2019-10-28  8:07       ` [dpdk-dev] [PATCH v5 1/1] " yasufum.o
2019-10-29 12:03         ` 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-dev] [PATCH v6 0/1] " yasufum.o
2019-11-01  9:04       ` [dpdk-dev] [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 [this message]
2019-11-05 11:41               ` Ananyev, Konstantin
2019-11-06 10:37                 ` Burakov, Anatoly
2019-11-08  3:19                   ` Yasufumi Ogawa
2019-11-13 21:43     ` [dpdk-dev] [PATCH v7 0/1] " yasufum.o
2019-11-13 21:43       ` [dpdk-dev] [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
2019-11-29  5:44                   ` Yasufumi Ogawa
2019-12-02 10:43                     ` Burakov, Anatoly
2019-12-05 20:13                       ` Yasufumi Ogawa
2019-11-14 12:55         ` David Marchand
2019-11-14 17:32         ` Ananyev, Konstantin
2019-11-27  8:48       ` [dpdk-dev] [PATCH v8 0/1] " Yasufumi Ogawa
2019-11-27  8:48         ` [dpdk-dev] [PATCH v8 1/1] " Yasufumi Ogawa
2019-12-06 10:44           ` Burakov, Anatoly
2019-12-06 13:18             ` Yasufumi Ogawa
2020-02-14  7:46             ` Yasufumi Ogawa
2020-02-14 15:08               ` David Marchand
2020-02-14 15:29                 ` Thomas Monjalon
2020-02-17 12:54                   ` Yasufumi Ogawa

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=d7a0729c-eb4d-d87a-4f7a-0d94627010e4@intel.com \
    --to=anatoly.burakov@intel.com \
    --cc=david.marchand@redhat.com \
    --cc=dev@dpdk.org \
    --cc=konstantin.ananyev@intel.com \
    --cc=ogawa.yasufumi@lab.ntt.co.jp \
    --cc=stable@dpdk.org \
    --cc=yasufum.o@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

DPDK patches and discussions

Archives are clonable:
	git clone --mirror http://inbox.dpdk.org/dev/0 dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 dev dev/ http://inbox.dpdk.org/dev \
		dev@dpdk.org
	public-inbox-index dev


Newsgroup available over NNTP:
	nntp://inbox.dpdk.org/inbox.dpdk.dev


AGPL code for this site: git clone https://public-inbox.org/ public-inbox