From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754705AbbCBWpu (ORCPT ); Mon, 2 Mar 2015 17:45:50 -0500 Received: from mail113-251.mail.alibaba.com ([205.204.113.251]:41960 "EHLO us-alimail-mta1.hst.scl.en.alidc.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753757AbbCBWpt (ORCPT ); Mon, 2 Mar 2015 17:45:49 -0500 X-Alimail-AntiSpam: AC=CONTINUE;BC=0.07423419|-1;FP=0|0|0|0|0|-1|-1|-1;HT=r41g03024;MF=gang.chen@sunrus.com.cn;PH=DS;RN=2;RT=2;SR=0; Message-ID: <54F4E84E.6080002@sunrus.com.cn> Date: Tue, 03 Mar 2015 06:46:38 +0800 From: Chen Gang S User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Chen Gang <762976180@qq.com>, "linux-kernel@vger.kernel.org" Subject: Fwd: [PATCH] mm: memcontrol: Let mem_cgroup_move_account() have effect only if MMU enabled References: <54F4E739.6040805@qq.com> In-Reply-To: <54F4E739.6040805@qq.com> X-Forwarded-Message-Id: <54F4E739.6040805@qq.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Just forward mail. -------- Forwarded Message -------- Subject: [PATCH] mm: memcontrol: Let mem_cgroup_move_account() have effect only if MMU enabled Date: Tue, 03 Mar 2015 06:42:01 +0800 From: Chen Gang <762976180@qq.com> To: hannes@cmpxchg.org, mhocko@suse.cz CC: cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org When !MMU, it will report warning. The related warning with allmodconfig under c6x: CC mm/memcontrol.o mm/memcontrol.c:2802:12: warning: 'mem_cgroup_move_account' defined but not used [-Wunused-function] static int mem_cgroup_move_account(struct page *page, ^ Signed-off-by: Chen Gang --- mm/memcontrol.c | 172 ++++++++++++++++++++++++++++---------------------------- 1 file changed, 86 insertions(+), 86 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 0c86945..80f26f5 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2785,92 +2785,6 @@ void mem_cgroup_split_huge_fixup(struct page *head) } #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ -/** - * mem_cgroup_move_account - move account of the page - * @page: the page - * @nr_pages: number of regular pages (>1 for huge pages) - * @from: mem_cgroup which the page is moved from. - * @to: mem_cgroup which the page is moved to. @from != @to. - * - * The caller must confirm following. - * - page is not on LRU (isolate_page() is useful.) - * - compound_lock is held when nr_pages > 1 - * - * This function doesn't do "charge" to new cgroup and doesn't do "uncharge" - * from old cgroup. - */ -static int mem_cgroup_move_account(struct page *page, - unsigned int nr_pages, - struct mem_cgroup *from, - struct mem_cgroup *to) -{ - unsigned long flags; - int ret; - - VM_BUG_ON(from == to); - VM_BUG_ON_PAGE(PageLRU(page), page); - /* - * The page is isolated from LRU. So, collapse function - * will not handle this page. But page splitting can happen. - * Do this check under compound_page_lock(). The caller should - * hold it. - */ - ret = -EBUSY; - if (nr_pages > 1 && !PageTransHuge(page)) - goto out; - - /* - * Prevent mem_cgroup_migrate() from looking at page->mem_cgroup - * of its source page while we change it: page migration takes - * both pages off the LRU, but page cache replacement doesn't. - */ - if (!trylock_page(page)) - goto out; - - ret = -EINVAL; - if (page->mem_cgroup != from) - goto out_unlock; - - spin_lock_irqsave(&from->move_lock, flags); - - if (!PageAnon(page) && page_mapped(page)) { - __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], - nr_pages); - __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], - nr_pages); - } - - if (PageWriteback(page)) { - __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK], - nr_pages); - __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_WRITEBACK], - nr_pages); - } - - /* - * It is safe to change page->mem_cgroup here because the page - * is referenced, charged, and isolated - we can't race with - * uncharging, charging, migration, or LRU putback. - */ - - /* caller should have done css_get */ - page->mem_cgroup = to; - spin_unlock_irqrestore(&from->move_lock, flags); - - ret = 0; - - local_irq_disable(); - mem_cgroup_charge_statistics(to, page, nr_pages); - memcg_check_events(to, page); - mem_cgroup_charge_statistics(from, page, -nr_pages); - memcg_check_events(from, page); - local_irq_enable(); -out_unlock: - unlock_page(page); -out: - return ret; -} - #ifdef CONFIG_MEMCG_SWAP static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg, bool charge) @@ -4822,6 +4736,92 @@ static struct page *mc_handle_file_pte(struct vm_area_struct *vma, return page; } +/** + * mem_cgroup_move_account - move account of the page + * @page: the page + * @nr_pages: number of regular pages (>1 for huge pages) + * @from: mem_cgroup which the page is moved from. + * @to: mem_cgroup which the page is moved to. @from != @to. + * + * The caller must confirm following. + * - page is not on LRU (isolate_page() is useful.) + * - compound_lock is held when nr_pages > 1 + * + * This function doesn't do "charge" to new cgroup and doesn't do "uncharge" + * from old cgroup. + */ +static int mem_cgroup_move_account(struct page *page, + unsigned int nr_pages, + struct mem_cgroup *from, + struct mem_cgroup *to) +{ + unsigned long flags; + int ret; + + VM_BUG_ON(from == to); + VM_BUG_ON_PAGE(PageLRU(page), page); + /* + * The page is isolated from LRU. So, collapse function + * will not handle this page. But page splitting can happen. + * Do this check under compound_page_lock(). The caller should + * hold it. + */ + ret = -EBUSY; + if (nr_pages > 1 && !PageTransHuge(page)) + goto out; + + /* + * Prevent mem_cgroup_migrate() from looking at page->mem_cgroup + * of its source page while we change it: page migration takes + * both pages off the LRU, but page cache replacement doesn't. + */ + if (!trylock_page(page)) + goto out; + + ret = -EINVAL; + if (page->mem_cgroup != from) + goto out_unlock; + + spin_lock_irqsave(&from->move_lock, flags); + + if (!PageAnon(page) && page_mapped(page)) { + __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], + nr_pages); + __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], + nr_pages); + } + + if (PageWriteback(page)) { + __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK], + nr_pages); + __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_WRITEBACK], + nr_pages); + } + + /* + * It is safe to change page->mem_cgroup here because the page + * is referenced, charged, and isolated - we can't race with + * uncharging, charging, migration, or LRU putback. + */ + + /* caller should have done css_get */ + page->mem_cgroup = to; + spin_unlock_irqrestore(&from->move_lock, flags); + + ret = 0; + + local_irq_disable(); + mem_cgroup_charge_statistics(to, page, nr_pages); + memcg_check_events(to, page); + mem_cgroup_charge_statistics(from, page, -nr_pages); + memcg_check_events(from, page); + local_irq_enable(); +out_unlock: + unlock_page(page); +out: + return ret; +} + static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma, unsigned long addr, pte_t ptent, union mc_target *target) { -- 1.9.3