DPDK patches and discussions
 help / color / mirror / Atom feed
From: Olivier Matz <olivier.matz@6wind.com>
To: Ali Alnubani <alialnu@mellanox.com>
Cc: Andrew Rybchenko <arybchenko@solarflare.com>,
	Anatoly Burakov <anatoly.burakov@intel.com>,
	"stable@dpdk.org" <stable@dpdk.org>,
	"dev@dpdk.org" <dev@dpdk.org>,
	Thomas Monjalon <thomasm@mellanox.com>,
	Raslan Darawsheh <rasland@mellanox.com>
Subject: Re: [dpdk-dev] [PATCH] mempool: fix slow allocation of large mempools
Date: Thu, 9 Jan 2020 18:27:41 +0100	[thread overview]
Message-ID: <20200109172741.GL22738@platinum> (raw)
In-Reply-To: <AM0PR05MB44011515B3267730EB53AA2BD7390@AM0PR05MB4401.eurprd05.prod.outlook.com>

Hi Ali,

On Thu, Jan 09, 2020 at 04:06:53PM +0000, Ali Alnubani wrote:
> Hi Olivier,
> 
> > -----Original Message-----
> > From: dev <dev-bounces@dpdk.org> On Behalf Of Olivier Matz
> > Sent: Thursday, January 9, 2020 3:28 PM
> > To: dev@dpdk.org
> > Cc: Andrew Rybchenko <arybchenko@solarflare.com>; Anatoly Burakov
> > <anatoly.burakov@intel.com>; stable@dpdk.org
> > Subject: [dpdk-dev] [PATCH] mempool: fix slow allocation of large mempools
> > 
> > When allocating a mempool which is larger than the largest available area, it
> > can take a lot of time:
> > 
> > a- the mempool calculate the required memory size, and tries
> >    to allocate it, it fails
> > b- then it tries to allocate the largest available area (this
> >    does not request new huge pages)
> > c- add this zone to the mempool, this triggers the allocation
> >    of a mem hdr, which request a new huge page
> > d- back to a- until mempool is populated or until there is no
> >    more memory
> > 
> > This can take a lot of time to finally fail (several minutes): in step
> > a- it takes all available hugepages on the system, then release them after it
> > fails.
> > 
> > The problem appeared with commit eba11e364614 ("mempool: reduce
> > wasted space on populate"), because smaller chunks are now allowed.
> > Previously, it had to be at least one page size, which is not the case in step b-.
> > 
> > To fix this, implement our own way to allocate the largest available area
> > instead of using the feature from memzone: if an allocation fails, try to divide
> > the size by 2 and retry. When the requested size falls below min_chunk_size,
> > stop and return an error.
> > 
> > Fixes: eba11e364614 ("mempool: reduce wasted space on populate")
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
> > ---
> 
> Testpmd (testpmd -n4 -- -i) fails to start after applying this patch with:
> """
> EAL: Error - exiting with code: 1
>   Cause: Creation of mbuf pool for socket 0 failed: File exists
> """
> 
> This is why the check ci/iol-mellanox-Performance is failing (not sure if the other tests are failing for the same reason).

Thanks for the report.

I should have retested after my "little rework"... :)
I'll send a v2 with this fix:

  --- a/lib/librte_mempool/rte_mempool.c
  +++ b/lib/librte_mempool/rte_mempool.c
  @@ -572,7 +572,7 @@ rte_mempool_populate_default(struct rte_mempool *mp)
   
                          max_alloc_size = RTE_MIN(max_alloc_size,
                                                  (size_t)mem_size) / 2;
  -               } while (max_alloc_size >= min_chunk_size);
  +               } while (mz == NULL && max_alloc_size >= min_chunk_size);
   
                  if (mz == NULL) {
                          ret = -rte_errno;

Olivier

  reply	other threads:[~2020-01-09 17:27 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-09 13:27 Olivier Matz
2020-01-09 13:57 ` Burakov, Anatoly
2020-01-09 16:06 ` Ali Alnubani
2020-01-09 17:27   ` Olivier Matz [this message]
2020-01-10  9:53 ` Andrew Rybchenko
2020-01-17  8:45   ` Olivier Matz
2020-01-17  9:51 ` [dpdk-dev] [PATCH v2] " Olivier Matz
2020-01-17 10:01   ` Olivier Matz
2020-01-17 10:09     ` Andrew Rybchenko
2020-01-20 10:12       ` Thomas Monjalon
2020-01-19 12:29   ` Ali Alnubani

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=20200109172741.GL22738@platinum \
    --to=olivier.matz@6wind.com \
    --cc=alialnu@mellanox.com \
    --cc=anatoly.burakov@intel.com \
    --cc=arybchenko@solarflare.com \
    --cc=dev@dpdk.org \
    --cc=rasland@mellanox.com \
    --cc=stable@dpdk.org \
    --cc=thomasm@mellanox.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
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).