From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754763Ab2IQQkG (ORCPT ); Mon, 17 Sep 2012 12:40:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40774 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753440Ab2IQQi7 (ORCPT ); Mon, 17 Sep 2012 12:38:59 -0400 From: Rafael Aquini To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Rusty Russell , "Michael S. Tsirkin" , Rik van Riel , Mel Gorman , Andi Kleen , Andrew Morton , Konrad Rzeszutek Wilk , Minchan Kim , Peter Zijlstra , "Paul E. McKenney" , aquini@redhat.com Subject: [PATCH v10 2/5] mm: introduce compaction and migration for ballooned pages Date: Mon, 17 Sep 2012 13:38:17 -0300 Message-Id: In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Memory fragmentation introduced by ballooning might reduce significantly the number of 2MB contiguous memory blocks that can be used within a guest, thus imposing performance penalties associated with the reduced number of transparent huge pages that could be used by the guest workload. This patch introduces the helper functions as well as the necessary changes to teach compaction and migration bits how to cope with pages which are part of a guest memory balloon, in order to make them movable by memory compaction procedures. Signed-off-by: Rafael Aquini --- mm/compaction.c | 47 ++++++++++++++++++++++++++++------------------- mm/migrate.c | 36 ++++++++++++++++++++++++++++++++++-- 2 files changed, 62 insertions(+), 21 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index 7fcd3a5..e50836b 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "internal.h" #if defined CONFIG_COMPACTION || defined CONFIG_CMA @@ -358,32 +359,40 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc, continue; } - if (!PageLRU(page)) - continue; - /* - * PageLRU is set, and lru_lock excludes isolation, - * splitting and collapsing (collapsing has already - * happened if PageLRU is set). + * It is possible to migrate LRU pages and balloon pages. + * Skip any other type of page. */ - if (PageTransHuge(page)) { - low_pfn += (1 << compound_order(page)) - 1; - continue; - } + if (PageLRU(page)) { + /* + * PageLRU is set, and lru_lock excludes isolation, + * splitting and collapsing (collapsing has already + * happened if PageLRU is set). + */ + if (PageTransHuge(page)) { + low_pfn += (1 << compound_order(page)) - 1; + continue; + } - if (!cc->sync) - mode |= ISOLATE_ASYNC_MIGRATE; + if (!cc->sync) + mode |= ISOLATE_ASYNC_MIGRATE; - lruvec = mem_cgroup_page_lruvec(page, zone); + lruvec = mem_cgroup_page_lruvec(page, zone); - /* Try isolate the page */ - if (__isolate_lru_page(page, mode) != 0) - continue; + /* Try isolate the page */ + if (__isolate_lru_page(page, mode) != 0) + continue; - VM_BUG_ON(PageTransCompound(page)); + VM_BUG_ON(PageTransCompound(page)); + + /* Successfully isolated */ + del_page_from_lru_list(page, lruvec, page_lru(page)); + } else if (unlikely(movable_balloon_page(page))) { + if (!isolate_balloon_page(page)) + continue; + } else + continue; - /* Successfully isolated */ - del_page_from_lru_list(page, lruvec, page_lru(page)); list_add(&page->lru, migratelist); cc->nr_migratepages++; nr_isolated++; diff --git a/mm/migrate.c b/mm/migrate.c index 77ed2d7..ec439f8 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -35,6 +35,7 @@ #include #include #include +#include #include @@ -79,7 +80,10 @@ void putback_lru_pages(struct list_head *l) list_del(&page->lru); dec_zone_page_state(page, NR_ISOLATED_ANON + page_is_file_cache(page)); - putback_lru_page(page); + if (unlikely(movable_balloon_page(page))) + putback_balloon_page(page); + else + putback_lru_page(page); } } @@ -799,6 +803,18 @@ static int __unmap_and_move(struct page *page, struct page *newpage, goto skip_unmap; } + if (unlikely(movable_balloon_page(page))) { + /* + * A ballooned page does not need any special attention from + * physical to virtual reverse mapping procedures. + * Skip any attempt to unmap PTEs or to remap swap cache, + * in order to avoid burning cycles at rmap level, and perform + * the page migration right away (proteced by page lock). + */ + rc = migrate_balloon_page(newpage, page, mode); + goto uncharge; + } + /* Establish migration ptes or remove ptes */ try_to_unmap(page, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS); @@ -814,7 +830,8 @@ skip_unmap: put_anon_vma(anon_vma); uncharge: - mem_cgroup_end_migration(mem, page, newpage, rc == 0); + mem_cgroup_end_migration(mem, page, newpage, + (rc == 0 || rc == BALLOON_MIGRATION_RETURN)); unlock: unlock_page(page); out: @@ -846,6 +863,21 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, goto out; rc = __unmap_and_move(page, newpage, force, offlining, mode); + + if (unlikely(rc == BALLOON_MIGRATION_RETURN)) { + /* + * A ballooned page has been migrated already. + * Now, it's the time to remove the old page from the isolated + * pageset list and handle it back to Buddy, wrap-up counters + * and return. + */ + dec_zone_page_state(page, NR_ISOLATED_ANON + + page_is_file_cache(page)); + list_del(&page->lru); + put_page(page); + __free_page(page); + return 0; + } out: if (rc != -EAGAIN) { /* -- 1.7.11.4