From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f69.google.com (mail-pl0-f69.google.com [209.85.160.69]) by kanga.kvack.org (Postfix) with ESMTP id 05A4D6B026F for ; Tue, 12 Jun 2018 03:16:45 -0400 (EDT) Received: by mail-pl0-f69.google.com with SMTP id 89-v6so13558834plc.1 for ; Tue, 12 Jun 2018 00:16:44 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id 33-v6sor78565ply.63.2018.06.12.00.16.43 for (Google Transport Security); Tue, 12 Jun 2018 00:16:43 -0700 (PDT) From: Nicholas Piggin Subject: [RFC PATCH 1/3] Revert "mm: always flush VMA ranges affected by zap_page_range" Date: Tue, 12 Jun 2018 17:16:19 +1000 Message-Id: <20180612071621.26775-2-npiggin@gmail.com> In-Reply-To: <20180612071621.26775-1-npiggin@gmail.com> References: <20180612071621.26775-1-npiggin@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: Nicholas Piggin , linuxppc-dev@lists.ozlabs.org, linux-arch@vger.kernel.org, "Aneesh Kumar K . V" , Minchan Kim , Mel Gorman , Nadav Amit , Andrew Morton , Linus Torvalds This reverts commit 4647706ebeee6e50f7b9f922b095f4ec94d581c3. Patch 99baac21e4585 ("mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem") provides a superset of the TLB flush coverage of this commit, and even includes in the changelog "this patch supersedes 'mm: Always flush VMA ranges affected by zap_page_range v2'". Reverting this avoids double flushing the TLB range, and the less efficient flush_tlb_range() call (the mmu_gather API is more precise about what ranges it invalidates). Signed-off-by: Nicholas Piggin --- mm/memory.c | 14 +------------- 1 file changed, 1 insertion(+), 13 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 7206a634270b..9d472e00fc2d 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1603,20 +1603,8 @@ void zap_page_range(struct vm_area_struct *vma, unsigned long start, tlb_gather_mmu(&tlb, mm, start, end); update_hiwater_rss(mm); mmu_notifier_invalidate_range_start(mm, start, end); - for ( ; vma && vma->vm_start < end; vma = vma->vm_next) { + for ( ; vma && vma->vm_start < end; vma = vma->vm_next) unmap_single_vma(&tlb, vma, start, end, NULL); - - /* - * zap_page_range does not specify whether mmap_sem should be - * held for read or write. That allows parallel zap_page_range - * operations to unmap a PTE and defer a flush meaning that - * this call observes pte_none and fails to flush the TLB. - * Rather than adding a complex API, ensure that no stale - * TLB entries exist when this call returns. - */ - flush_tlb_range(vma, start, end); - } - mmu_notifier_invalidate_range_end(mm, start, end); tlb_finish_mmu(&tlb, start, end); } -- 2.17.0