From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <dev-bounces@dpdk.org>
Received: from dpdk.org (dpdk.org [92.243.14.124])
	by inbox.dpdk.org (Postfix) with ESMTP id 15884A0598;
	Sat, 18 Apr 2020 12:00:30 +0200 (CEST)
Received: from [92.243.14.124] (localhost [127.0.0.1])
	by dpdk.org (Postfix) with ESMTP id D62EC1E92D;
	Sat, 18 Apr 2020 12:00:29 +0200 (CEST)
Received: from huawei.com (szxga03-in.huawei.com [45.249.212.189])
 by dpdk.org (Postfix) with ESMTP id 3655B1E92D;
 Sat, 18 Apr 2020 12:00:15 +0200 (CEST)
Received: from dggeml406-hub.china.huawei.com (unknown [172.30.72.53])
 by Forcepoint Email with ESMTP id 74C2A9AA3CAA01D24015;
 Sat, 18 Apr 2020 18:00:12 +0800 (CST)
Received: from DGGEML424-HUB.china.huawei.com (10.1.199.41) by
 dggeml406-hub.china.huawei.com (10.3.17.50) with Microsoft SMTP Server (TLS)
 id 14.3.487.0; Sat, 18 Apr 2020 18:00:11 +0800
Received: from DGGEML529-MBX.china.huawei.com ([169.254.6.71]) by
 dggeml424-hub.china.huawei.com ([10.1.199.41]) with mapi id 14.03.0487.000;
 Sat, 18 Apr 2020 18:00:09 +0800
From: "Lilijun (Jerry)" <jerry.lilijun@huawei.com>
To: "'dev@dpdk.org'" <dev@dpdk.org>, "'stable@dpdk.org'" <stable@dpdk.org>
Thread-Topic: rte_hash bug: can't iterate all entries when deleting keys in
 rte_hash iterate loop.
Thread-Index: AdYVYgMWpFq5RHj2QzGPZAYcXd4MGQ==
Date: Sat, 18 Apr 2020 10:00:09 +0000
Message-ID: <40280F65B1B0B44E8089ED31C01616EBA496BC2A@dggeml529-mbx.china.huawei.com>
Accept-Language: zh-CN, en-US
Content-Language: zh-CN
X-MS-Has-Attach: 
X-MS-TNEF-Correlator: 
x-originating-ip: [10.173.251.98]
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-CFilter-Loop: Reflected
Subject: [dpdk-dev] rte_hash bug: can't iterate all entries when deleting
 keys in rte_hash iterate loop.
X-BeenThere: dev@dpdk.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <https://mails.dpdk.org/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://mails.dpdk.org/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <https://mails.dpdk.org/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

Hi all,

    In my test, entries can't be cleanup in rte_hash table when deleting ke=
ys in rte_hash iterate loop. The test steps:
    1.  create a hash table table1 with limit 30000, ext bucket enabled,  a=
nd insert 30000 entries into this hash table.
    2.  create a larger hash table table2 with limit 60000, , ext bucket en=
abled.
    3.  iterate all entries of table1 and insert them to the table2. Insert=
 new 10000 entries to this table2.
    4.  Then flush all entries from table2 by deleting keys in rte_hash ite=
rate loop. But there are still some keys leaked in table2.

    From my analysis, the keys idx are stored in rte_hash main bucket key s=
lots and extend bucket key stots.=20
    We iterate every no empty Keys in h->buckets and h->buckets_ext from st=
art to last.=20
    When deleting keys the function __rte_hash_compact_ll() may move last_b=
kt's key to previous bucket in order to compact extend bucket list.
    If the previous bucket has been iterated, the moved key may be missed f=
or users.=20
    Then those missed keys are leaked and rte_hash table can't be cleanup.

    Now I retry the iterate and delete keys, that can avoid this bug.=20

    Is there any ideas or solutions on this bug?   Thanks.

Jerry.