From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751380AbdBXLlE (ORCPT ); Fri, 24 Feb 2017 06:41:04 -0500 Received: from mga05.intel.com ([192.55.52.43]:23851 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751312AbdBXLkl (ORCPT ); Fri, 24 Feb 2017 06:40:41 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,200,1484035200"; d="scan'208";a="69710332" From: Aaron Lu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Dave Hansen , Tim Chen , Andrew Morton , Ying Huang , Aaron Lu Subject: [PATCH 4/5] mm: add force_free_pages in zap_pte_range Date: Fri, 24 Feb 2017 19:40:35 +0800 Message-Id: <20170224114036.15621-5-aaron.lu@intel.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170224114036.15621-1-aaron.lu@intel.com> References: <20170224114036.15621-1-aaron.lu@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org force_flush in zap_pte_range is set in the following 2 conditions: 1 When no more batches can be allocated (either due to no memory or MAX_GATHER_BATCH_COUNT has reached) to store those to-be-freed page pointers; 2 When a TLB_only flush is needed before dropping the PTE lock to avoid a race condition as explained in commit 1cf35d47712d ("mm: split 'tlb_flush_mmu()' into tlb flushing and memory freeing parts"). Once force_flush is set, the pages accumulated thus far will all be freed. Since there is no need to do page free if condition 2 occurred, add a new variable named force_free_pages to decide if page free should be done and it will only only be set if condition 1 occured. With this change, the page accumulation will not be interrupted by condition 2 anymore. In the meantime, rename force_flush to force_flush_tlb for condition 2. Signed-off-by: Aaron Lu --- mm/memory.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index eb8b17fc1b2b..7d1fe74084be 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1185,7 +1185,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, struct zap_details *details) { struct mm_struct *mm = tlb->mm; - int force_flush = 0; + int force_flush_tlb = 0, force_free_pages = 0; int rss[NR_MM_COUNTERS]; spinlock_t *ptl; pte_t *start_pte; @@ -1232,7 +1232,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, */ if (unlikely(details && details->ignore_dirty)) continue; - force_flush = 1; + force_flush_tlb = 1; set_page_dirty(page); } if (pte_young(ptent) && @@ -1244,7 +1244,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, if (unlikely(page_mapcount(page) < 0)) print_bad_pte(vma, addr, ptent, page); if (unlikely(__tlb_remove_page(tlb, page))) { - force_flush = 1; + force_free_pages = 1; addr += PAGE_SIZE; break; } @@ -1272,18 +1272,14 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, arch_leave_lazy_mmu_mode(); /* Do the actual TLB flush before dropping ptl */ - if (force_flush) + if (force_flush_tlb) { + force_flush_tlb = 0; tlb_flush_mmu_tlbonly(tlb); + } pte_unmap_unlock(start_pte, ptl); - /* - * If we forced a TLB flush (either due to running out of - * batch buffers or because we needed to flush dirty TLB - * entries before releasing the ptl), free the batched - * memory too. Restart if we didn't do everything. - */ - if (force_flush) { - force_flush = 0; + if (force_free_pages) { + force_free_pages = 0; tlb_flush_mmu_free(tlb); if (addr != end) goto again; -- 2.9.3