[PATCH v6 17/18] mm/memory-failure: increase queued recovery work's priority
From: james.morse@arm.com (James Morse)
Date: 2018-09-21 22:19:06
Also in:
kvmarm, linux-acpi, linux-mm
Subsystem:
hwpoison memory failure handling, memory management, the rest · Maintainers:
Miaohe Lin, Andrew Morton, Linus Torvalds
arm64 can take an NMI-like error notification when user-space steps in some corrupt memory. APEI's GHES code will call memory_failure_queue() to schedule the recovery work. We then return to user-space, possibly taking the fault again. Currently the arch code unconditionally signals user-space from this path, so we don't get stuck in this loop, but the affected process never benefits from memory_failure()s recovery work. To fix this we need to know the recovery work will run before we get back to user-space. Increase the priority of the recovery work by scheduling it on the system_highpri_wq, then try to bump the current task off this CPU so that the recovery work starts immediately. Reported-by: Xie XiuQi <redacted> Signed-off-by: James Morse <james.morse@arm.com> Reviewed-by: Punit Agrawal <redacted> Tested-by: Tyler Baicar <redacted> Tested-by: gengdongjiu <redacted> CC: Xie XiuQi <redacted> CC: gengdongjiu <redacted> --- mm/memory-failure.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 0cd3de3550f0..4e7b115cea5a 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c@@ -56,6 +56,7 @@ #include <linux/memory_hotplug.h> #include <linux/mm_inline.h> #include <linux/memremap.h> +#include <linux/preempt.h> #include <linux/kfifo.h> #include <linux/ratelimit.h> #include <linux/page-isolation.h>
@@ -1454,6 +1455,7 @@ static DEFINE_PER_CPU(struct memory_failure_cpu, memory_failure_cpu); */ void memory_failure_queue(unsigned long pfn, int flags) { + int cpu = smp_processor_id(); struct memory_failure_cpu *mf_cpu; unsigned long proc_flags; struct memory_failure_entry entry = {
@@ -1463,11 +1465,14 @@ void memory_failure_queue(unsigned long pfn, int flags) mf_cpu = &get_cpu_var(memory_failure_cpu); spin_lock_irqsave(&mf_cpu->lock, proc_flags); - if (kfifo_put(&mf_cpu->fifo, entry)) - schedule_work_on(smp_processor_id(), &mf_cpu->work); - else + if (kfifo_put(&mf_cpu->fifo, entry)) { + queue_work_on(cpu, system_highpri_wq, &mf_cpu->work); + set_tsk_need_resched(current); + preempt_set_need_resched(); + } else { pr_err("Memory failure: buffer overflow when queuing memory failure at %#lx\n", pfn); + } spin_unlock_irqrestore(&mf_cpu->lock, proc_flags); put_cpu_var(memory_failure_cpu); }
--
2.19.0