From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f42.google.com (mail-pa0-f42.google.com [209.85.220.42]) by kanga.kvack.org (Postfix) with ESMTP id 1F64F6B0035 for ; Thu, 31 Jul 2014 20:12:11 -0400 (EDT) Received: by mail-pa0-f42.google.com with SMTP id lf10so4587483pab.15 for ; Thu, 31 Jul 2014 17:12:10 -0700 (PDT) Received: from lgeamrelo02.lge.com (lgeamrelo02.lge.com. [156.147.1.126]) by mx.google.com with ESMTP id vd9si7680964pab.148.2014.07.31.17.12.07 for ; Thu, 31 Jul 2014 17:12:09 -0700 (PDT) Message-ID: <53DADB56.3050103@lge.com> Date: Fri, 01 Aug 2014 09:12:06 +0900 From: Gioh Kim MIME-Version: 1.0 Subject: Re: [PATCHv2] CMA/HOTPLUG: clear buffer-head lru before page migration References: <53D9A86B.20208@lge.com> <20140731155703.a8bc3b77af913c8b3a63090a@linux-foundation.org> In-Reply-To: <20140731155703.a8bc3b77af913c8b3a63090a@linux-foundation.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: =?UTF-8?B?J+q5gOykgOyImCc=?= , Marek Szyprowski , Minchan Kim , Laura Abbott , Michal Nazarewicz , Alexander Viro , Johannes Weiner , linux-kernel@vger.kernel.org, linux-mm@kvack.org, ????????? , 'Chanho Min' 2014-08-01 i??i ? 7:57, Andrew Morton i?' e,?: > On Thu, 31 Jul 2014 11:22:35 +0900 Gioh Kim wrote: > >> The previous PATCH inserts invalidate_bh_lrus() only into CMA code. >> HOTPLUG needs also dropping bh of lru. >> So v2 inserts invalidate_bh_lrus() into both of CMA and HOTPLUG. >> >> >> ---------------------------- 8< ---------------------------- >> The bh must be free to migrate a page at which bh is mapped. >> The reference count of bh is increased when it is installed >> into lru so that the bh of lru must be freed before migrating the page. >> >> This frees every bh of lru. We could free only bh of migrating page. >> But searching lru sometimes costs more than invalidating entire lru. >> >> Signed-off-by: Gioh Kim >> Acked-by: Michal Nazarewicz >> --- >> mm/memory_hotplug.c | 1 + >> mm/page_alloc.c | 2 ++ >> 2 files changed, 3 insertions(+) >> >> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >> index a3797d3..1c5454f 100644 >> --- a/mm/memory_hotplug.c >> +++ b/mm/memory_hotplug.c >> @@ -1672,6 +1672,7 @@ repeat: >> lru_add_drain_all(); >> cond_resched(); >> drain_all_pages(); >> + invalidate_bh_lrus(); > > Both of these calls should have a comment explaining why > invalidate_bh_lrus() is being called. > >> } >> >> pfn = scan_movable_pages(start_pfn, end_pfn); >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> index b99643d4..c00dedf 100644 >> --- a/mm/page_alloc.c >> +++ b/mm/page_alloc.c >> @@ -6369,6 +6369,8 @@ int alloc_contig_range(unsigned long start, unsigned long end, >> if (ret) >> return ret; >> >> + invalidate_bh_lrus(); >> + >> ret = __alloc_contig_migrate_range(&cc, start, end); >> if (ret) >> goto done; > > I do feel that this change is likely to be beneficial, but I don't want > to apply such a patch until I know what its effects are upon all > alloc_contig_range() callers. Especially hugetlb. I'm very sorry to hear that. How can I check the effects? > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- 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