On Fri, Jun 22, 2018 at 04:34:48PM +0800, kbuild test robot wrote:
> Hi Byungchul,
>
> Thank you for the patch! Perhaps something to improve:
>
> [auto build test WARNING on rcu/rcu/next]
> [also build test WARNING on v4.18-rc1 next-20180622]
> [if your patch is applied to the wrong git tree, please drop us a note to
> help improve the system]
>
> url:
> https://github.com/0day-ci/linux/commits/Byungchul-Park/rcu-Refactor-rcu_-nmi-irq-_-enter-exit/20180622-141334
> base: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
> rcu/next
> reproduce: make htmldocs
>
> All warnings (new ones prefixed by >>):
>
> WARNING: convert(1) not found, for SVG to PDF conversion install
> ImageMagick (https://www.imagemagick.org)
> >> kernel/rcu/tree.c:778: warning: Function parameter or member 'irq' not
> >> described in 'rcu_nmi_exit_common'
> >> kernel/rcu/tree.c:938: warning: Function parameter or member 'irq' not
> >> described in 'rcu_nmi_enter_common'
It is complaining about the docbook function-header comment. It wants
the "irq" parameter described, something like this:
* @irq: Is this call from rcu_irq_enter?
And similar for rcu_nmi_exit_common().
Thanx, Paul
> include/net/cfg80211.h:4216: warning: Function parameter or member
> 'wext.ibss' not described in 'wireless_dev'
> include/net/cfg80211.h:4216: warning: Function parameter or member
> 'wext.connect' not described in 'wireless_dev'
> include/net/cfg80211.h:4216: warning: Function parameter or member
> 'wext.keys' not described in 'wireless_dev'
> include/net/cfg80211.h:4216: warning: Function parameter or member
> 'wext.ie' not described in 'wireless_dev'
> include/net/cfg80211.h:4216: warning: Function parameter or member
> 'wext.ie_len' not described in 'wireless_dev'
> include/net/cfg80211.h:4216: warning: Function parameter or member
> 'wext.bssid' not described in 'wireless_dev'
> include/net/cfg80211.h:4216: warning: Function parameter or member
> 'wext.ssid' not described in 'wireless_dev'
> include/net/cfg80211.h:4216: warning: Function parameter or member
> 'wext.default_key' not described in 'wireless_dev'
> include/net/cfg80211.h:4216: warning: Function parameter or member
> 'wext.default_mgmt_key' not described in 'wireless_dev'
> include/net/cfg80211.h:4216: warning: Function parameter or member
> 'wext.prev_bssid_valid' not described in 'wireless_dev'
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2282: warning: Function parameter or member
> 'radiotap_timestamp.units_pos' not described in 'ieee80211_hw'
> include/net/mac80211.h:2282: warning: Function parameter or member
> 'radiotap_timestamp.accuracy' not described in 'ieee80211_hw'
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:955: warning: Function parameter or member
> 'control.rates' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'control.rts_cts_rate_idx' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'control.use_rts' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'control.use_cts_prot' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'control.short_preamble' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'control.skip_table' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'control.jiffies' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'control.vif' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'control.hw_key' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'control.flags' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'control.enqueue_time' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member 'ack'
> not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'ack.cookie' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'status.rates' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'status.ack_signal' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'status.ampdu_ack_len' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'status.ampdu_len' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'status.antenna' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'status.tx_time' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'status.is_valid_ack_signal' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'status.status_driver_data' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'driver_rates' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member 'pad'
> not described in 'ieee80211_tx_info'
> include/net/mac80211.h:955: warning: Function parameter or member
> 'rate_driver_data' not described in 'ieee80211_tx_info'
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
> include/net/mac80211.h:2083: warning: bad line: >
>
> vim +778 kernel/rcu/tree.c
>
> 19dd1591f kernel/rcutree.c Frederic Weisbecker 2012-06-04 765
> 19dd1591f kernel/rcutree.c Frederic Weisbecker 2012-06-04 766 /**
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 767 *
> rcu_nmi_exit_common - inform RCU of exit from NMI context
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 768 *
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 769 * If we are
> returning from the outermost NMI handler that interrupted an
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 770 * RCU-idle
> period, update rdtp->dynticks and rdtp->dynticks_nmi_nesting
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 771 * to let
> the RCU grace-period handling know that the CPU is back to
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 772 * being
> RCU-idle.
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 773 *
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 774 * If you
> add or remove a call to rcu_nmi_exit_common(), be sure to test
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 775 * with
> CONFIG_RCU_EQS_DEBUG=y.
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 776 */
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 777 static
> __always_inline void rcu_nmi_exit_common(bool irq)
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 @778 {
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 779 struct
> rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 780
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 781 /*
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 782 *
> Check for ->dynticks_nmi_nesting underflow and bad ->dynticks.
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 783 * (We
> are exiting an NMI handler, so RCU better be paying attention
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 784 * to
> us!)
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 785 */
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 786
> WARN_ON_ONCE(rdtp->dynticks_nmi_nesting <= 0);
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 787
> WARN_ON_ONCE(rcu_dynticks_curr_cpu_in_eqs());
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 788
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 789 /*
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 790 * If
> the nesting level is not 1, the CPU wasn't RCU-idle, so
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 791 *
> leave it in non-RCU-idle state.
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 792 */
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 793 if
> (rdtp->dynticks_nmi_nesting != 1) {
> dec98900e kernel/rcu/tree.c Paul E. McKenney 2017-10-04 794
> trace_rcu_dyntick(TPS("--="), rdtp->dynticks_nmi_nesting,
> rdtp->dynticks_nmi_nesting - 2, rdtp->dynticks);
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 795
> WRITE_ONCE(rdtp->dynticks_nmi_nesting, /* No store tearing. */
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 796
> rdtp->dynticks_nmi_nesting - 2);
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 797
> return;
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 798 }
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 799
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 800 /* This
> NMI interrupted an RCU-idle CPU, restore RCU-idleness. */
> dec98900e kernel/rcu/tree.c Paul E. McKenney 2017-10-04 801
> trace_rcu_dyntick(TPS("Startirq"), rdtp->dynticks_nmi_nesting, 0,
> rdtp->dynticks);
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 802
> WRITE_ONCE(rdtp->dynticks_nmi_nesting, 0); /* Avoid store tearing. */
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 803
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 804 if (irq)
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 805
> rcu_prepare_for_idle();
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 806
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 807
> rcu_dynticks_eqs_enter();
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 808
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 809 if (irq)
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 810
> rcu_dynticks_task_enter();
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 811 }
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 812
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 813 /**
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 814 *
> rcu_nmi_exit - inform RCU of exit from NMI context
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 815 */
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 816 void
> rcu_nmi_exit(void)
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 817 {
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 818
> rcu_nmi_exit_common(false);
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 819 }
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 820
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 821 /**
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 822 *
> rcu_irq_exit - inform RCU that current CPU is exiting irq towards idle
> 64db4cfff kernel/rcutree.c Paul E. McKenney 2008-12-18 823 *
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 824 * Exit from
> an interrupt handler, which might possibly result in entering
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 825 * idle
> mode, in other words, leaving the mode in which read-side critical
> 7c9906ca5 kernel/rcu/tree.c Paul E. McKenney 2015-10-31 826 * sections
> can occur. The caller must have disabled interrupts.
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 827 *
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 828 * This code
> assumes that the idle loop never does anything that might
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 829 * result in
> unbalanced calls to irq_enter() and irq_exit(). If your
> 58721f5da kernel/rcu/tree.c Paul E. McKenney 2017-10-03 830 *
> architecture's idle loop violates this assumption, RCU will give you what
> 58721f5da kernel/rcu/tree.c Paul E. McKenney 2017-10-03 831 * you
> deserve, good and hard. But very infrequently and irreproducibly.
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 832 *
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 833 * Use
> things like work queues to work around this limitation.
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 834 *
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 835 * You have
> been warned.
> c0da313e0 kernel/rcu/tree.c Paul E. McKenney 2017-09-22 836 *
> c0da313e0 kernel/rcu/tree.c Paul E. McKenney 2017-09-22 837 * If you
> add or remove a call to rcu_irq_exit(), be sure to test with
> c0da313e0 kernel/rcu/tree.c Paul E. McKenney 2017-09-22 838 *
> CONFIG_RCU_EQS_DEBUG=y.
> 64db4cfff kernel/rcutree.c Paul E. McKenney 2008-12-18 839 */
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 840 void
> rcu_irq_exit(void)
> 64db4cfff kernel/rcutree.c Paul E. McKenney 2008-12-18 841 {
> b04db8e19 kernel/rcu/tree.c Frederic Weisbecker 2017-11-06 842
> lockdep_assert_irqs_disabled();
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 843
> rcu_nmi_exit_common(true);
> 7c9906ca5 kernel/rcu/tree.c Paul E. McKenney 2015-10-31 844 }
> 7c9906ca5 kernel/rcu/tree.c Paul E. McKenney 2015-10-31 845
> 7c9906ca5 kernel/rcu/tree.c Paul E. McKenney 2015-10-31 846 /*
> 7c9906ca5 kernel/rcu/tree.c Paul E. McKenney 2015-10-31 847 * Wrapper
> for rcu_irq_exit() where interrupts are enabled.
> c0da313e0 kernel/rcu/tree.c Paul E. McKenney 2017-09-22 848 *
> c0da313e0 kernel/rcu/tree.c Paul E. McKenney 2017-09-22 849 * If you
> add or remove a call to rcu_irq_exit_irqson(), be sure to test
> c0da313e0 kernel/rcu/tree.c Paul E. McKenney 2017-09-22 850 * with
> CONFIG_RCU_EQS_DEBUG=y.
> 7c9906ca5 kernel/rcu/tree.c Paul E. McKenney 2015-10-31 851 */
> 7c9906ca5 kernel/rcu/tree.c Paul E. McKenney 2015-10-31 852 void
> rcu_irq_exit_irqson(void)
> 7c9906ca5 kernel/rcu/tree.c Paul E. McKenney 2015-10-31 853 {
> 7c9906ca5 kernel/rcu/tree.c Paul E. McKenney 2015-10-31 854
> unsigned long flags;
> 7c9906ca5 kernel/rcu/tree.c Paul E. McKenney 2015-10-31 855
> 7c9906ca5 kernel/rcu/tree.c Paul E. McKenney 2015-10-31 856
> local_irq_save(flags);
> 7c9906ca5 kernel/rcu/tree.c Paul E. McKenney 2015-10-31 857
> rcu_irq_exit();
> 23b5c8fa0 kernel/rcutree.c Paul E. McKenney 2010-09-07 858
> local_irq_restore(flags);
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 859 }
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 860
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 861 /*
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 862 * Exit an
> RCU extended quiescent state, which can be either the
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 863 * idle loop
> or adaptive-tickless usermode execution.
> 51a1fd30f kernel/rcu/tree.c Paul E. McKenney 2017-10-03 864 *
> 51a1fd30f kernel/rcu/tree.c Paul E. McKenney 2017-10-03 865 * We
> crowbar the ->dynticks_nmi_nesting field to DYNTICK_IRQ_NONIDLE to
> 51a1fd30f kernel/rcu/tree.c Paul E. McKenney 2017-10-03 866 * allow for
> the possibility of usermode upcalls messing up our count of
> 51a1fd30f kernel/rcu/tree.c Paul E. McKenney 2017-10-03 867 * interrupt
> nesting level during the busy period that is just now starting.
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 868 */
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 869 static void
> rcu_eqs_exit(bool user)
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 870 {
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 871 struct
> rcu_dynticks *rdtp;
> 84585aa8b kernel/rcu/tree.c Paul E. McKenney 2017-10-04 872 long
> oldval;
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 873
> b04db8e19 kernel/rcu/tree.c Frederic Weisbecker 2017-11-06 874
> lockdep_assert_irqs_disabled();
> c9d4b0af9 kernel/rcutree.c Christoph Lameter 2013-08-31 875 rdtp =
> this_cpu_ptr(&rcu_dynticks);
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 876 oldval
> = rdtp->dynticks_nesting;
> 1ce46ee59 kernel/rcu/tree.c Paul E. McKenney 2015-05-05 877
> WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && oldval < 0);
> 51a1fd30f kernel/rcu/tree.c Paul E. McKenney 2017-10-03 878 if
> (oldval) {
> 51a1fd30f kernel/rcu/tree.c Paul E. McKenney 2017-10-03 879
> rdtp->dynticks_nesting++;
> 9dd238e28 kernel/rcu/tree.c Paul E. McKenney 2017-10-05 880
> return;
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 881 }
> 9dd238e28 kernel/rcu/tree.c Paul E. McKenney 2017-10-05 882
> rcu_dynticks_task_exit();
> 9dd238e28 kernel/rcu/tree.c Paul E. McKenney 2017-10-05 883
> rcu_dynticks_eqs_exit();
> 9dd238e28 kernel/rcu/tree.c Paul E. McKenney 2017-10-05 884
> rcu_cleanup_after_idle();
> 9dd238e28 kernel/rcu/tree.c Paul E. McKenney 2017-10-05 885
> trace_rcu_dyntick(TPS("End"), rdtp->dynticks_nesting, 1, rdtp->dynticks);
> e68bbb266 kernel/rcu/tree.c Paul E. McKenney 2017-10-05 886
> WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !user &&
> !is_idle_task(current));
> 2342172fd kernel/rcu/tree.c Paul E. McKenney 2017-10-05 887
> WRITE_ONCE(rdtp->dynticks_nesting, 1);
> 6136d6e48 kernel/rcu/tree.c Paul E. McKenney 2017-10-03 888
> WRITE_ONCE(rdtp->dynticks_nmi_nesting, DYNTICK_IRQ_NONIDLE);
> 3a5924052 kernel/rcu/tree.c Paul E. McKenney 2013-10-04 889 }
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 890
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 891 /**
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 892 *
> rcu_idle_exit - inform RCU that current CPU is leaving idle
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 893 *
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 894 * Exit idle
> mode, in other words, -enter- the mode in which RCU
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 895 * read-side
> critical sections can occur.
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 896 *
> c0da313e0 kernel/rcu/tree.c Paul E. McKenney 2017-09-22 897 * If you
> add or remove a call to rcu_idle_exit(), be sure to test with
> c0da313e0 kernel/rcu/tree.c Paul E. McKenney 2017-09-22 898 *
> CONFIG_RCU_EQS_DEBUG=y.
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 899 */
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 900 void
> rcu_idle_exit(void)
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 901 {
> c5d900bf6 kernel/rcutree.c Frederic Weisbecker 2012-07-11 902
> unsigned long flags;
> c5d900bf6 kernel/rcutree.c Frederic Weisbecker 2012-07-11 903
> c5d900bf6 kernel/rcutree.c Frederic Weisbecker 2012-07-11 904
> local_irq_save(flags);
> cb349ca95 kernel/rcutree.c Paul E. McKenney 2012-09-04 905
> rcu_eqs_exit(false);
> c5d900bf6 kernel/rcutree.c Frederic Weisbecker 2012-07-11 906
> local_irq_restore(flags);
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 907 }
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 908
> d1ec4c34c kernel/rcu/tree.c Paul E. McKenney 2015-05-13 909 #ifdef
> CONFIG_NO_HZ_FULL
> 9b2e4f188 kernel/rcutree.c Paul E. McKenney 2011-09-30 910 /**
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 911 *
> rcu_user_exit - inform RCU that we are exiting userspace.
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 912 *
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 913 * Exit RCU
> idle mode while entering the kernel because it can
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 914 * run a RCU
> read side critical section anytime.
> c0da313e0 kernel/rcu/tree.c Paul E. McKenney 2017-09-22 915 *
> c0da313e0 kernel/rcu/tree.c Paul E. McKenney 2017-09-22 916 * If you
> add or remove a call to rcu_user_exit(), be sure to test with
> c0da313e0 kernel/rcu/tree.c Paul E. McKenney 2017-09-22 917 *
> CONFIG_RCU_EQS_DEBUG=y.
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 918 */
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 919 void
> rcu_user_exit(void)
> adf5091e6 kernel/rcutree.c Frederic Weisbecker 2012-06-28 920 {
> 91d1aa43d kernel/rcutree.c Frederic Weisbecker 2012-11-27 921
> rcu_eqs_exit(1);
> c5d900bf6 kernel/rcutree.c Frederic Weisbecker 2012-07-11 922 }
> d1ec4c34c kernel/rcu/tree.c Paul E. McKenney 2015-05-13 923 #endif /*
> CONFIG_NO_HZ_FULL */
> 19dd1591f kernel/rcutree.c Frederic Weisbecker 2012-06-04 924
> 19dd1591f kernel/rcutree.c Frederic Weisbecker 2012-06-04 925 /**
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 926 *
> rcu_nmi_enter_common - inform RCU of entry to NMI context
> 64db4cfff kernel/rcutree.c Paul E. McKenney 2008-12-18 927 *
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 928 * If the
> CPU was idle from RCU's viewpoint, update rdtp->dynticks and
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 929 *
> rdtp->dynticks_nmi_nesting to let the RCU grace-period handling know
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 930 * that the
> CPU is active. This implementation permits nested NMIs, as
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 931 * long as
> the nesting level does not overflow an int. (You will probably
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 932 * run out
> of stack space first.)
> c0da313e0 kernel/rcu/tree.c Paul E. McKenney 2017-09-22 933 *
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 934 * If you
> add or remove a call to rcu_nmi_enter_common(), be sure to test
> c0da313e0 kernel/rcu/tree.c Paul E. McKenney 2017-09-22 935 * with
> CONFIG_RCU_EQS_DEBUG=y.
> 64db4cfff kernel/rcutree.c Paul E. McKenney 2008-12-18 936 */
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 937 static
> __always_inline void rcu_nmi_enter_common(bool irq)
> 64db4cfff kernel/rcutree.c Paul E. McKenney 2008-12-18 @938 {
> c9d4b0af9 kernel/rcutree.c Christoph Lameter 2013-08-31 939 struct
> rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
> 84585aa8b kernel/rcu/tree.c Paul E. McKenney 2017-10-04 940 long
> incby = 2;
> 64db4cfff kernel/rcutree.c Paul E. McKenney 2008-12-18 941
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 942 /*
> Complain about underflow. */
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 943
> WARN_ON_ONCE(rdtp->dynticks_nmi_nesting < 0);
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 944
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 945 /*
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 946 * If
> idle from RCU viewpoint, atomically increment ->dynticks
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 947 * to
> mark non-idle and increment ->dynticks_nmi_nesting by one.
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 948 *
> Otherwise, increment ->dynticks_nmi_nesting by two. This means
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 949 * if
> ->dynticks_nmi_nesting is equal to one, we are guaranteed
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 950 * to
> be in the outermost NMI handler that interrupted an RCU-idle
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 951 *
> period (observation due to Andy Lutomirski).
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 952 */
> 02a5c550b kernel/rcu/tree.c Paul E. McKenney 2016-11-02 953 if
> (rcu_dynticks_curr_cpu_in_eqs()) {
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 954
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 955
> if (irq)
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 956
> rcu_dynticks_task_exit();
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 957
> 2625d469b kernel/rcu/tree.c Paul E. McKenney 2016-11-02 958
> rcu_dynticks_eqs_exit();
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 959
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 960
> if (irq)
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 961
> rcu_cleanup_after_idle();
> 1e8a49734 kernel/rcu/tree.c Byungchul Park 2018-06-22 962
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 963
> incby = 1;
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 964 }
> bd2b879a1 kernel/rcu/tree.c Paul E. McKenney 2017-10-04 965
> trace_rcu_dyntick(incby == 1 ? TPS("Endirq") : TPS("++="),
> bd2b879a1 kernel/rcu/tree.c Paul E. McKenney 2017-10-04 966
> rdtp->dynticks_nmi_nesting,
> dec98900e kernel/rcu/tree.c Paul E. McKenney 2017-10-04 967
> rdtp->dynticks_nmi_nesting + incby, rdtp->dynticks);
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 968
> WRITE_ONCE(rdtp->dynticks_nmi_nesting, /* Prevent store tearing. */
> fd581a91a kernel/rcu/tree.c Paul E. McKenney 2017-10-02 969
> rdtp->dynticks_nmi_nesting + incby);
> 734d16801 kernel/rcu/tree.c Paul E. McKenney 2014-11-21 970
> barrier();
> 64db4cfff kernel/rcutree.c Paul E. McKenney 2008-12-18 971 }
> 64db4cfff kernel/rcutree.c Paul E. McKenney 2008-12-18 972
>
> :::::: The code at line 778 was first introduced by commit
> :::::: fd581a91ac16187625ec509414d08d37827472c4 rcu: Move
> rcu_nmi_{enter,exit}() to prepare for consolidation
>
> :::::: TO: Paul E. McKenney <[email protected]>
> :::::: CC: Paul E. McKenney <[email protected]>
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all Intel Corporation
