From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id BD8486B0033 for ; Sun, 5 Feb 2017 23:03:02 -0500 (EST) Received: by mail-pg0-f71.google.com with SMTP id d185so95340174pgc.2 for ; Sun, 05 Feb 2017 20:03:02 -0800 (PST) Received: from out0-142.mail.aliyun.com (out0-142.mail.aliyun.com. [140.205.0.142]) by mx.google.com with ESMTP id r14si32578192pli.158.2017.02.05.20.03.01 for ; Sun, 05 Feb 2017 20:03:01 -0800 (PST) Reply-To: "Hillf Danton" From: "Hillf Danton" References: <20170205161252.85004-1-zi.yan@sent.com> <20170205161252.85004-4-zi.yan@sent.com> In-Reply-To: <20170205161252.85004-4-zi.yan@sent.com> Subject: Re: [PATCH v3 03/14] mm: use pmd lock instead of racy checks in zap_pmd_range() Date: Mon, 06 Feb 2017 12:02:54 +0800 Message-ID: <001101d2802d$e4ec9800$aec5c800$@alibaba-inc.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Language: zh-cn Sender: owner-linux-mm@kvack.org List-ID: To: 'Zi Yan' , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kirill.shutemov@linux.intel.com Cc: akpm@linux-foundation.org, minchan@kernel.org, vbabka@suse.cz, mgorman@techsingularity.net, n-horiguchi@ah.jp.nec.com, khandual@linux.vnet.ibm.com, zi.yan@cs.rutgers.edu, 'Zi Yan' On February 06, 2017 12:13 AM Zi Yan wrote: > > @@ -1233,33 +1233,31 @@ static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, > struct zap_details *details) > { > pmd_t *pmd; > + spinlock_t *ptl; > unsigned long next; > > pmd = pmd_offset(pud, addr); > + ptl = pmd_lock(vma->vm_mm, pmd); > do { > next = pmd_addr_end(addr, end); > if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { > if (next - addr != HPAGE_PMD_SIZE) { > VM_BUG_ON_VMA(vma_is_anonymous(vma) && > !rwsem_is_locked(&tlb->mm->mmap_sem), vma); > - __split_huge_pmd(vma, pmd, addr, false, NULL); > - } else if (zap_huge_pmd(tlb, vma, pmd, addr)) > - goto next; > + __split_huge_pmd_locked(vma, pmd, addr, false); > + } else if (__zap_huge_pmd_locked(tlb, vma, pmd, addr)) > + continue; > /* fall through */ > } > - /* > - * Here there can be other concurrent MADV_DONTNEED or > - * trans huge page faults running, and if the pmd is > - * none or trans huge it can change under us. This is > - * because MADV_DONTNEED holds the mmap_sem in read > - * mode. > - */ > - if (pmd_none_or_trans_huge_or_clear_bad(pmd)) > - goto next; > + > + if (pmd_none_or_clear_bad(pmd)) > + continue; > + spin_unlock(ptl); > next = zap_pte_range(tlb, vma, pmd, addr, next, details); > -next: > cond_resched(); > + spin_lock(ptl); > } while (pmd++, addr = next, addr != end); spin_lock() is appointed to the bench of pmd_lock(). > + spin_unlock(ptl); > > return addr; > } -- 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