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From: Andrew Rybchenko <arybchenko@solarflare.com>
To: Olivier Matz <olivier.matz@6wind.com>, <dev@dpdk.org>
Cc: Ali Alnubani <alialnu@mellanox.com>,
	Anatoly Burakov <anatoly.burakov@intel.com>,
	Raslan Darawsheh <rasland@mellanox.com>, <stable@dpdk.org>,
	Thomas Monjalon <thomas@monjalon.net>
Subject: Re: [dpdk-dev] [PATCH v2] mempool: fix slow allocation of large mempools
Date: Fri, 17 Jan 2020 13:09:05 +0300	[thread overview]
Message-ID: <d27f108e-3689-0b63-344f-20e525a93291@solarflare.com> (raw)
In-Reply-To: <20200117100117.GX22738@platinum>

On 1/17/20 1:01 PM, Olivier Matz wrote:
> On Fri, Jan 17, 2020 at 10:51:49AM +0100, Olivier Matz wrote:
>> 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>
> 
> Sorry I forgot to report Anatoly's ack on v1
> http://patchwork.dpdk.org/patch/64370/
> 
> Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>

Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>


  reply	other threads:[~2020-01-17 10:09 UTC|newest]

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

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