DPDK patches and discussions
 help / color / mirror / Atom feed
From: "Burakov, Anatoly" <anatoly.burakov@intel.com>
To: "Mohakud, Amiya Ranjan" <amohakud@rbbn.com>, dpdk-dev <dev@dpdk.org>
Cc: "Dey, Souvik" <sodey@rbbn.com>
Subject: Re: [dpdk-dev] eal: DPDK: 18.11.6 version rte_eal_init() function cleans the runtime directory in 5.4.35 kernel
Date: Thu, 15 Oct 2020 19:01:09 +0100
Message-ID: <58888db2-a3c5-befc-6886-d510c7fd6646@intel.com> (raw)
In-Reply-To: <DM6PR03MB3547649C0113C1826DB82A30B9020@DM6PR03MB3547.namprd03.prod.outlook.com>

On 15-Oct-20 5:14 PM, Mohakud, Amiya Ranjan wrote:
> + Souvik
> 
> *From:*Mohakud, Amiya Ranjan
> *Sent:* 15 October 2020 21:38
> *To:* Burakov, Anatoly <anatoly.burakov@intel.com>; dpdk-dev <dev@dpdk.org>
> *Subject:* RE: [dpdk-dev] eal: DPDK: 18.11.6 version rte_eal_init() 
> function cleans the runtime directory in 5.4.35 kernel
> 
> Hi Anatoly - Thanks for helping on this.
> 
> I am not aware, where the primary process re-creates the files. Can you 
> please point me to that? As per my code browsing and understanding, I 
> can see, fbarray_memzone file gets created in 
> rte_eal_memzone_init()->rte_fbarray_init() and it stays there till 
> eal_clean_runtime_dir() gets called towards end of rte_eal_init(). This 
> does not get deleted in 4.19 kernel, but in 5.4, it does.
> 
> /I'm not sure i understand. Primary process is supposed to clear the
> files. It will then recreate them. Are you suggesting that it's clearing
> them *after* it has created them?/
> 
> /
> /Going by my observation, the file highlighted below gets deleted by the 
> time rte_eal_init() is over.
> 
> srwxr-xr-x 1 root root      0 Oct 15 11:24 mp_socket
> 
> -rw------- 1 root root  12432 Oct 15 11:24 hugepage_info
> 
> -rw------- 1 root root 188416 Oct 15 11:24 fbarray_memzone
> 
> -rw------- 1 root root 397312 Oct 15 11:24 fbarray_memseg-2048k-0-1
> 
> -rw------- 1 root root 397312 Oct 15 11:24 fbarray_memseg-2048k-0-0
> 
> -rw------- 1 root root 397312 Oct 15 11:24 fbarray_memseg-2048k-0-3
> 
> -rw------- 1 root root 397312 Oct 15 11:24 fbarray_memseg-2048k-0-2
> 
> -rw------- 1 root root  16529 Oct 15 11:24 config
> 
> Please reach out to me for further clarification.
> 
> Regards
> 
> Amiya

Hi,

Sorry, yes, you're right (it's been a while since i looked at the code), 
it removes unused stuff at the end of init. There's even a comment 
explaining why that's done :D

It sounds like closing the file descriptor also drops the lock. This 
locking business is a huge pain because we have to support old kernels 
which don't have the only sane file locking implementation that Linux has.

While i wouldn't go as far as to say "this is a kernel regression" as 
most likely it's me who's at fault here, but this definitely shouldn't 
happen. Unfortunately, i won't be online for the next two weeks, but 
i'll definitely look into this after i'm back, so thanks for your report.

-- 
Thanks,
Anatoly

  reply	other threads:[~2020-10-15 18:01 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <DM6PR03MB3547EDC8BAAD1DA17AE4470EB9020@DM6PR03MB3547.namprd03.prod.outlook.com>
2020-10-15 13:26 ` Mohakud, Amiya Ranjan
2020-10-15 13:52   ` Burakov, Anatoly
2020-10-15 14:43     ` Mohakud, Amiya Ranjan
2020-10-15 15:08       ` Burakov, Anatoly
2020-10-15 16:07         ` Mohakud, Amiya Ranjan
2020-10-15 16:14           ` Mohakud, Amiya Ranjan
2020-10-15 18:01             ` Burakov, Anatoly [this message]
2020-10-15 18:34               ` Burakov, Anatoly
2020-10-16  5:34                 ` Mohakud, Amiya Ranjan
2020-10-22  7:12                   ` Mohakud, Amiya Ranjan
     [not found]                     ` <DM6PR03MB3547C263D4E20B3DD124AD43B91D0@DM6PR03MB3547.namprd03.prod.outlook.com>
2020-10-28  7:00                       ` Mohakud, Amiya Ranjan
2020-10-29 15:51                         ` Burakov, Anatoly
2020-10-29 17:10                           ` Burakov, Anatoly
2020-10-29 17:40                             ` Mohakud, Amiya Ranjan
2020-10-30 10:00                               ` Burakov, Anatoly
2021-01-04  7:53                                 ` Mohakud, Amiya Ranjan

Reply instructions:

You may reply publicly 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=58888db2-a3c5-befc-6886-d510c7fd6646@intel.com \
    --to=anatoly.burakov@intel.com \
    --cc=amohakud@rbbn.com \
    --cc=dev@dpdk.org \
    --cc=sodey@rbbn.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

This inbox may be cloned and mirrored by anyone:

	git clone --mirror https://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/ https://inbox.dpdk.org/dev \
		dev@dpdk.org
	public-inbox-index dev

Example config snippet for mirrors.
Newsgroup available over NNTP:
	nntp://inbox.dpdk.org/inbox.dpdk.dev


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