From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f198.google.com (mail-pg1-f198.google.com [209.85.215.198]) by kanga.kvack.org (Postfix) with ESMTP id 5ACBB8E0001 for ; Wed, 12 Sep 2018 05:27:21 -0400 (EDT) Received: by mail-pg1-f198.google.com with SMTP id s11-v6so788253pgv.9 for ; Wed, 12 Sep 2018 02:27:21 -0700 (PDT) Received: from alexa-out-blr-01.qualcomm.com (alexa-out-blr-01.qualcomm.com. [103.229.18.197]) by mx.google.com with ESMTPS id k4-v6si469773pfc.328.2018.09.12.02.27.19 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 12 Sep 2018 02:27:19 -0700 (PDT) From: Arun KS Subject: [RFC] memory_hotplug: Free pages as pageblock_order Date: Wed, 12 Sep 2018 14:56:45 +0530 Message-Id: <1536744405-16752-1-git-send-email-arunks@codeaurora.org> Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, dan.j.williams@intel.com, mhocko@suse.com, vbabka@suse.cz, pasha.tatashin@oracle.com, iamjoonsoo.kim@lge.com, osalvador@suse.de, arunks@codeaurora.org, malat@debian.org, gregkh@linuxfoundation.org, yasu.isimatu@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: arunks.linux@gmail.com, vinmenon@codeaurora.org When free pages are done with pageblock_order, time spend on coalescing pages by buddy allocator can be reduced. With section size of 256MB, hot add latency of a single section shows improvement from 50-60 ms to less than 1 ms, hence improving the hot add latency by 60%. If this looks okey, I'll modify users of set_online_page_callback and resend clean patch. Signed-off-by: Arun KS --- include/linux/memory_hotplug.h | 1 + mm/memory_hotplug.c | 52 ++++++++++++++++++++++++++++++++++++------ 2 files changed, 46 insertions(+), 7 deletions(-) diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 34a2822..447047d 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -88,6 +88,7 @@ extern int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn, extern void __offline_isolated_pages(unsigned long, unsigned long); typedef void (*online_page_callback_t)(struct page *page); +typedef int (*online_pages_callback_t)(struct page *page, unsigned int order); extern int set_online_page_callback(online_page_callback_t callback); extern int restore_online_page_callback(online_page_callback_t callback); diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 38d94b7..853104d 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -662,19 +662,57 @@ static void generic_online_page(struct page *page) __online_page_free(page); } +static int generic_online_pages(struct page *page, unsigned int order); +static online_pages_callback_t online_pages_callback = generic_online_pages; + +static int generic_online_pages(struct page *page, unsigned int order) +{ + unsigned long nr_pages = 1 << order; + struct page *p = page; + unsigned int loop; + + for (loop = 0 ; loop < nr_pages ; loop++, p++) { + __ClearPageReserved(p); + set_page_count(p, 0); + } + adjust_managed_page_count(page, nr_pages); + init_page_count(page); + __free_pages(page, order); + + return 0; +} + +static int online_pages_blocks(unsigned long start_pfn, unsigned long nr_pages) +{ + unsigned long pages_per_block = (1 << pageblock_order); + unsigned long nr_pageblocks = nr_pages / pages_per_block; +// unsigned long rem_pages = nr_pages % pages_per_block; + int i, ret, onlined_pages = 0; + struct page *page; + + for (i = 0 ; i < nr_pageblocks ; i++) { + page = pfn_to_page(start_pfn + (i * pages_per_block)); + ret = (*online_pages_callback)(page, pageblock_order); + if (!ret) + onlined_pages += pages_per_block; + else if (ret > 0) + onlined_pages += ret; + } +/* + if (rem_pages) + onlined_pages += online_page_single(start_pfn + i, rem_pages); +*/ + + return onlined_pages; +} + static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, void *arg) { - unsigned long i; unsigned long onlined_pages = *(unsigned long *)arg; - struct page *page; if (PageReserved(pfn_to_page(start_pfn))) - for (i = 0; i < nr_pages; i++) { - page = pfn_to_page(start_pfn + i); - (*online_page_callback)(page); - onlined_pages++; - } + onlined_pages = online_pages_blocks(start_pfn, nr_pages); online_mem_sections(start_pfn, start_pfn + nr_pages); -- 1.9.1