Commit bcb362eb authored Jun 04, 2024 by Yu Liao

arm64/mpam: Fix softlockup when reading mondata

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I9SXQ8



--------------------------------

resctrl_dom_mon_data() call do_device_sync() wait for other CPU to respond
IPI, which is expensive (up to a few ms). resctrl_dom_mon_data() may be
called hundreds of times by resctrl_group_mondata_show(), causing soft
lockup.

Fix this by adding a cond_resched between each loop.

Do the same for resctrl_group_update_domain_ctrls().

Fixes: 8d7469cd ("arm64/mpam: Integrate monitor data for Memory Bandwidth if cdp enabled")
Signed-off-by: Yu Liao <liaoyu15@huawei.com>

parent 3b7f6009

arch/arm64/kernel/mpam/mpam_ctrlmon.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -285,6 +285,7 @@ static void resctrl_group_update_domain_ctrls(struct rdtgroup *rdtgrp,
		resctrl_cdp_mpamid_map_val(entry->closid.reqpartid,
		cfg[i].conf_type, closid.reqpartid);
		resctrl_dom_ctrl_config(cdp_both_ctrl, r, dom, &para);
		cond_resched();
		}
		}
		}
		@@ -658,6 +659,8 @@ int resctrl_group_mondata_show(struct seq_file m, void arg)
		r->rid), type, md.u.mon);

		usage += resctrl_dom_mon_data(r, d, md.priv);

		cond_resched();
		}
		}