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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 2 Aug 2019 00:07:43 +0100 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp22036.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x71N7g4J13173504 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 1 Aug 2019 23:07:42 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DB431B2064; Thu, 1 Aug 2019 23:07:42 +0000 (GMT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BC9B4B205F; Thu, 1 Aug 2019 23:07:42 +0000 (GMT) Received: from paulmck-ThinkPad-W541 (unknown [9.70.82.154]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Thu, 1 Aug 2019 23:07:42 +0000 (GMT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id 2426916C9A3D; Thu, 1 Aug 2019 16:07:44 -0700 (PDT) Date: Thu, 1 Aug 2019 16:07:44 -0700 From: "Paul E. McKenney" To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org Subject: [PATCH tip/core/rcu 0/18] No-CBs cblist updates for v5.3-rc2 Reply-To: paulmck@linux.ibm.com MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 19080123-2213-0000-0000-000003B873FA X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00011535; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000287; SDB=6.01240744; UDB=6.00654300; IPR=6.01022167; MB=3.00028000; MTD=3.00000008; XFM=3.00000015; UTC=2019-08-01 23:07:47 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19080123-2214-0000-0000-00005F7BA2F1 Message-Id: <20190801230744.GA19115@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-08-01_09:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=13 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=536 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908010244 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello! This series reduces memory footprint (RCU callbacks posted by no-CBs CPUs) by causing the no-CBs CPUs to use the existing ->cblist segmented callback list. This allows these callbacks to take advantage of RCU grace periods that were started by something other than the corresponding rcuog kthread: 1. Use separate flag to indicate disabled ->cblist. 2. Use separate flag to indicate offloaded ->cblist. 3. Add checks for offloaded callback processing. 4. Make rcutree_migrate_callbacks() start at leaf rcu_node structure. 5. Check for deferred nocb wakeups before nohz_full early exit. 6. Remove deferred wakeup checks for extended quiescent states. 7. Allow lockless use of rcu_segcblist_restempty(). 8. Allow lockless use of rcu_segcblist_empty(). 9. Leave ->cblist enabled for no-CBs CPUs. 10. Use rcu_segcblist for no-CBs CPUs. 11. Remove obsolete nocb_head and nocb_tail fields. 12. Remove obsolete nocb_q_count and nocb_q_count_lazy fields. 13. Remove obsolete nocb_cb_tail and nocb_cb_head fields. 14. Remove obsolete nocb_gp_head and nocb_gp_tail fields. 15. Use build-time no-CBs check in rcu_do_batch(). 16. Use build-time no-CBs check in rcu_core(). 17. Use build-time no-CBs check in rcu_pending(). 18. Suppress uninitialized false-positive in nocb_gp_wait(). Thanx, Paul ------------------------------------------------------------------------ include/linux/rcu_segcblist.h | 2 include/trace/events/rcu.h | 1 kernel/rcu/rcu_segcblist.c | 64 +++- kernel/rcu/rcu_segcblist.h | 16 - kernel/rcu/tree.c | 188 +++++++------ kernel/rcu/tree.h | 29 -- kernel/rcu/tree_plugin.h | 588 ++++++++++++++---------------------------- 7 files changed, 374 insertions(+), 514 deletions(-)