From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f70.google.com (mail-pa0-f70.google.com [209.85.220.70]) by kanga.kvack.org (Postfix) with ESMTP id D91FC6B0005 for ; Fri, 17 Jun 2016 07:23:43 -0400 (EDT) Received: by mail-pa0-f70.google.com with SMTP id b13so125635985pat.3 for ; Fri, 17 Jun 2016 04:23:43 -0700 (PDT) Received: from szxga03-in.huawei.com (szxga03-in.huawei.com. [119.145.14.66]) by mx.google.com with ESMTPS id n8si16540828paw.216.2016.06.17.04.23.42 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 17 Jun 2016 04:23:42 -0700 (PDT) Message-ID: <5763DC85.8080707@huawei.com> Date: Fri, 17 Jun 2016 19:18:29 +0800 From: zhong jiang MIME-Version: 1.0 Subject: Re: [PATCH] mm: fix account pmd page to the process References: <1466076971-24609-1-git-send-email-zhongjiang@huawei.com> <20160616154214.GA12284@dhcp22.suse.cz> In-Reply-To: <20160616154214.GA12284@dhcp22.suse.cz> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On 2016/6/16 23:42, Michal Hocko wrote: > On Thu 16-06-16 19:36:11, zhongjiang wrote: >> From: zhong jiang >> >> when a process acquire a pmd table shared by other process, we >> increase the account to current process. otherwise, a race result >> in other tasks have set the pud entry. so it no need to increase it. >> >> Signed-off-by: zhong jiang >> --- >> mm/hugetlb.c | 5 ++--- >> 1 file changed, 2 insertions(+), 3 deletions(-) >> >> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >> index 19d0d08..3b025c5 100644 >> --- a/mm/hugetlb.c >> +++ b/mm/hugetlb.c >> @@ -4189,10 +4189,9 @@ pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) >> if (pud_none(*pud)) { >> pud_populate(mm, pud, >> (pmd_t *)((unsigned long)spte & PAGE_MASK)); >> - } else { >> + } else >> put_page(virt_to_page(spte)); >> - mm_inc_nr_pmds(mm); >> - } > The code is quite puzzling but is this correct? Shouldn't we rather do > mm_dec_nr_pmds(mm) in that path to undo the previous inc? Yes, you are right. I will modify it in V2. Thanks zhongjiang > >> + >> spin_unlock(ptl); >> out: >> pte = (pte_t *)pmd_alloc(mm, pud, addr); >> -- >> 1.8.3.1 -- 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