Web* Scan the leaves of the rcu_node hierarchy for the rcu_state structure. * Note that if there is a singleton rcu_node tree with but one rcu_node * structure, this loop -will- visit the rcu_node structure. It is still * a leaf node, even if it is also the root node. */ #define rcu_for_each_leaf_node(rnp) \ for ((rnp) = rcu_first_leaf_node ... WebIf your system has more than 1,024 CPUs (or more than 512 CPUs on a 32-bit system), then RCU will automatically add more levels to the tree. For example, if you are crazy enough to build a 64-bit system with 65,536 CPUs, RCU would configure the rcu_node tree as follows: . RCU currently permits up to a four-level tree, which on a 64-bit system accommodates up …
Using RCU’s CPU Stall Detector - Linux kernel
Web* Re: [syzbot] INFO: rcu detected stall in ext4_file_write_iter (6) [not found] <[email protected]> @ 2024-02-08 14:15 ` syzbot 0 siblings, 0 replies; 9+ messages in thread From: syzbot @ 2024-02-08 14:15 UTC (permalink / raw) To: hdanton, linux-kernel, syzkaller-bugs Hello, syzbot has tested the proposed patch but the … WebJan 21, 2024 · Such systems will also need to boot with skew_tick=1 to avoid massive lock contention on the leaf rcu_node ‑>lock fields. This fanout can also be set at boot time: rcutree.rcu_fanout_leaf= sets the number of CPUs to assign to each leaf-level rcu_node structure. This defaults to 16 CPUs. shut out the light
A Tour Through TREE_RCU’s Expedited Grace Periods
Web[ 1161.661459] INFO: rcu_preempt detected stalls on CPUs/tasks: [ 1161.661763] Tasks blocked on level-0 rcu_node (CPUs 0-3): [ 1161.661840] Tasks blocked on level-0 … WebIf Tasks C and D also arrive at this point, they will compute the same desired grace-period sequence number, and see that both leaf rcu_node structures already have that value recorded. They will therefore block on their respective rcu_node structures’ ->exp_wq[1] fields, as shown below: WebRCU: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=1 NR_IRQS:16 nr_irqs:16 16 mxc_clocksource_init 24000000 Switching to timer-based delay loop, resolution 41ns sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 89478484971ns clocksource mxc_timer1: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 79635851949 ns … shut out the light springsteen