From patchwork Fri May 1 16:45:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Morse X-Patchwork-Id: 11522861 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 82F721805 for ; Fri, 1 May 2020 16:46:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7414E24957 for ; Fri, 1 May 2020 16:46:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729089AbgEAQqC (ORCPT ); Fri, 1 May 2020 12:46:02 -0400 Received: from foss.arm.com ([217.140.110.172]:43758 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728896AbgEAQqB (ORCPT ); Fri, 1 May 2020 12:46:01 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id DB59431B; Fri, 1 May 2020 09:46:00 -0700 (PDT) Received: from melchizedek.cambridge.arm.com (melchizedek.cambridge.arm.com [10.1.196.50]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0797F3F305; Fri, 1 May 2020 09:45:58 -0700 (PDT) From: James Morse To: linux-mm@kvack.org, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Naoya Horiguchi Cc: Andrew Morton , Rafael Wysocki , Len Brown , Tony Luck , Borislav Petkov , Catalin Marinas , Will Deacon , Mark Rutland , Tyler Baicar , Xie XiuQi , James Morse Subject: [PATCH v2 1/3] mm/memory-failure: Add memory_failure_queue_kick() Date: Fri, 1 May 2020 17:45:41 +0100 Message-Id: <20200501164543.24423-2-james.morse@arm.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20200501164543.24423-1-james.morse@arm.com> References: <20200501164543.24423-1-james.morse@arm.com> MIME-Version: 1.0 Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org The GHES code calls memory_failure_queue() from IRQ context to schedule work on the current CPU so that memory_failure() can sleep. For synchronous memory errors the arch code needs to know any signals that memory_failure() will trigger are pending before it returns to user-space, possibly when exiting from the IRQ. Add a helper to kick the memory failure queue, to ensure the scheduled work has happened. This has to be called from process context, so may have been migrated from the original cpu. Pass the cpu the work was queued on. Change memory_failure_work_func() to permit being called on the 'wrong' cpu. Signed-off-by: James Morse Tested-by: Tyler Baicar Acked-by: Naoya Horiguchi --- include/linux/mm.h | 1 + mm/memory-failure.c | 15 ++++++++++++++- 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 5a323422d783..c606dbbfa5e1 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3012,6 +3012,7 @@ enum mf_flags { }; extern int memory_failure(unsigned long pfn, int flags); extern void memory_failure_queue(unsigned long pfn, int flags); +extern void memory_failure_queue_kick(int cpu); extern int unpoison_memory(unsigned long pfn); extern int get_hwpoison_page(struct page *page); #define put_hwpoison_page(page) put_page(page) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index a96364be8ab4..c4afb407bf0f 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1493,7 +1493,7 @@ static void memory_failure_work_func(struct work_struct *work) unsigned long proc_flags; int gotten; - mf_cpu = this_cpu_ptr(&memory_failure_cpu); + mf_cpu = container_of(work, struct memory_failure_cpu, work); for (;;) { spin_lock_irqsave(&mf_cpu->lock, proc_flags); gotten = kfifo_get(&mf_cpu->fifo, &entry); @@ -1507,6 +1507,19 @@ static void memory_failure_work_func(struct work_struct *work) } } +/* + * Process memory_failure work queued on the specified CPU. + * Used to avoid return-to-userspace racing with the memory_failure workqueue. + */ +void memory_failure_queue_kick(int cpu) +{ + struct memory_failure_cpu *mf_cpu; + + mf_cpu = &per_cpu(memory_failure_cpu, cpu); + cancel_work_sync(&mf_cpu->work); + memory_failure_work_func(&mf_cpu->work); +} + static int __init memory_failure_init(void) { struct memory_failure_cpu *mf_cpu;