From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f72.google.com (mail-pa0-f72.google.com [209.85.220.72]) by kanga.kvack.org (Postfix) with ESMTP id 8DA736B0005 for ; Wed, 18 May 2016 17:53:49 -0400 (EDT) Received: by mail-pa0-f72.google.com with SMTP id yl2so86976381pac.2 for ; Wed, 18 May 2016 14:53:49 -0700 (PDT) Received: from mail-pf0-x22c.google.com (mail-pf0-x22c.google.com. [2607:f8b0:400e:c00::22c]) by mx.google.com with ESMTPS id v80si605519pfj.199.2016.05.18.14.53.48 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 18 May 2016 14:53:48 -0700 (PDT) Received: by mail-pf0-x22c.google.com with SMTP id 206so22698994pfu.0 for ; Wed, 18 May 2016 14:53:48 -0700 (PDT) Date: Wed, 18 May 2016 14:53:46 -0700 (PDT) From: David Rientjes Subject: [patch] mm, thp: khugepaged should scan when sleep value is written Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: "Kirill A. Shutemov" , Andrea Arcangeli , linux-mm@kvack.org, linux-kernel@vger.kernel.org If a large value is written to scan_sleep_millisecs, for example, that period must lapse before khugepaged will wake up for periodic collapsing. If this value is tuned to 1 day, for example, and then re-tuned to its default 10s, khugepaged will still wait for a day before scanning again. This patch causes khugepaged to wakeup immediately when the value is changed and then sleep until that value is rewritten or the new value lapses. Signed-off-by: David Rientjes --- mm/huge_memory.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -89,6 +89,7 @@ static unsigned int khugepaged_full_scans; static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000; /* during fragmentation poll the hugepage allocator once every minute */ static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000; +static unsigned long khugepaged_sleep_expire; static struct task_struct *khugepaged_thread __read_mostly; static DEFINE_MUTEX(khugepaged_mutex); static DEFINE_SPINLOCK(khugepaged_mm_lock); @@ -467,6 +468,7 @@ static ssize_t scan_sleep_millisecs_store(struct kobject *kobj, return -EINVAL; khugepaged_scan_sleep_millisecs = msecs; + khugepaged_sleep_expire = 0; wake_up_interruptible(&khugepaged_wait); return count; @@ -494,6 +496,7 @@ static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj, return -EINVAL; khugepaged_alloc_sleep_millisecs = msecs; + khugepaged_sleep_expire = 0; wake_up_interruptible(&khugepaged_wait); return count; @@ -2797,15 +2800,25 @@ static void khugepaged_do_scan(void) put_page(hpage); } +static bool khugepaged_should_wakeup(void) +{ + return kthread_should_stop() || + time_after_eq(jiffies, khugepaged_sleep_expire); +} + static void khugepaged_wait_work(void) { if (khugepaged_has_work()) { - if (!khugepaged_scan_sleep_millisecs) + const unsigned long scan_sleep_jiffies = + msecs_to_jiffies(khugepaged_scan_sleep_millisecs); + + if (!scan_sleep_jiffies) return; + khugepaged_sleep_expire = jiffies + scan_sleep_jiffies; wait_event_freezable_timeout(khugepaged_wait, - kthread_should_stop(), - msecs_to_jiffies(khugepaged_scan_sleep_millisecs)); + khugepaged_should_wakeup(), + scan_sleep_jiffies); return; } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org