From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:44774 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732400AbeGJS1Z (ORCPT ); Tue, 10 Jul 2018 14:27:25 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Cannon Matthews , Andrew Morton , Mike Kravetz , Michal Hocko , Andres Lagar-Cavilla , Peter Feiner , Greg Thelen , Linus Torvalds Subject: [PATCH 4.4 16/47] mm: hugetlb: yield when prepping struct pages Date: Tue, 10 Jul 2018 20:24:40 +0200 Message-Id: <20180710182337.820113168@linuxfoundation.org> In-Reply-To: <20180710182337.047502999@linuxfoundation.org> References: <20180710182337.047502999@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cannon Matthews commit 520495fe96d74e05db585fc748351e0504d8f40d upstream. When booting with very large numbers of gigantic (i.e. 1G) pages, the operations in the loop of gather_bootmem_prealloc, and specifically prep_compound_gigantic_page, takes a very long time, and can cause a softlockup if enough pages are requested at boot. For example booting with 3844 1G pages requires prepping (set_compound_head, init the count) over 1 billion 4K tail pages, which takes considerable time. Add a cond_resched() to the outer loop in gather_bootmem_prealloc() to prevent this lockup. Tested: Booted with softlockup_panic=1 hugepagesz=1G hugepages=3844 and no softlockup is reported, and the hugepages are reported as successfully setup. Link: http://lkml.kernel.org/r/20180627214447.260804-1-cannonmatthews@google.com Signed-off-by: Cannon Matthews Reviewed-by: Andrew Morton Reviewed-by: Mike Kravetz Acked-by: Michal Hocko Cc: Andres Lagar-Cavilla Cc: Peter Feiner Cc: Greg Thelen Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/hugetlb.c | 1 + 1 file changed, 1 insertion(+) --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2038,6 +2038,7 @@ static void __init gather_bootmem_preall */ if (hstate_is_gigantic(h)) adjust_managed_page_count(page, 1 << h->order); + cond_resched(); } }