From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9D0B8C77B6C for ; Thu, 13 Apr 2023 05:55:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229787AbjDMFzz (ORCPT ); Thu, 13 Apr 2023 01:55:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229689AbjDMFzy (ORCPT ); Thu, 13 Apr 2023 01:55:54 -0400 Received: from ubuntu20 (unknown [193.203.214.57]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 024864ED8 for ; Wed, 12 Apr 2023 22:55:52 -0700 (PDT) Received: by ubuntu20 (Postfix, from userid 1003) id AE1D7E196E; Thu, 13 Apr 2023 05:55:51 +0000 (UTC) From: Yang Yang To: akpm@linux-foundation.org, david@redhat.com Cc: yang.yang29@zte.com.cn, imbrenda@linux.ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ran.xiaokai@zte.com.cn, xu.xin.sc@gmail.com, xu.xin16@zte.com.cn, Xuexin Jiang Subject: [PATCH v7 3/6] ksm: add ksm zero pages for each process Date: Thu, 13 Apr 2023 13:55:47 +0800 Message-Id: <20230413055547.181107-1-yang.yang29@zte.com.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: <202304131346489021903@zte.com.cn> References: <202304131346489021903@zte.com.cn> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: xu xin As the number of ksm zero pages is not included in ksm_merging_pages per process when enabling use_zero_pages, it's unclear of how many actual pages are merged by KSM. To let users accurately estimate their memory demands when unsharing KSM zero-pages, it's necessary to show KSM zero- pages per process. In addition, it help users to know the actual KSM profit because KSM-placed zero pages are also benefit from KSM. since unsharing zero pages placed by KSM accurately is achieved, then tracking empty pages merging and unmerging is not a difficult thing any longer. Since we already have /proc//ksm_stat, just add the information of 'ksm_zero_pages' in it. Signed-off-by: xu xin Cc: Claudio Imbrenda Cc: David Hildenbrand Cc: Xuexin Jiang Cc: Xiaokai Ran Cc: Yang Yang --- fs/proc/base.c | 3 +++ include/linux/ksm.h | 10 ++++++---- include/linux/mm_types.h | 11 +++++++++-- mm/ksm.c | 2 +- mm/memory.c | 4 ++-- 5 files changed, 21 insertions(+), 9 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index ab9fa5b1b6be..235182cd143d 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3211,6 +3211,9 @@ static int proc_pid_ksm_stat(struct seq_file *m, struct pid_namespace *ns, seq_printf(m, "ksm_merging_pages %lu\n", mm->ksm_merging_pages); seq_printf(m, "ksm_merge_type %s\n", ksm_merge_type(mm)); seq_printf(m, "ksm_process_profit %ld\n", ksm_process_profit(mm)); +#ifdef CONFIG_KSM_ZERO_PAGES_TRACK + seq_printf(m, "ksm_zero_pages %lu\n", mm->ksm_zero_pages); +#endif mmput(mm); } diff --git a/include/linux/ksm.h b/include/linux/ksm.h index ea628d2a9105..2da40af9ad4d 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -100,22 +100,24 @@ static inline void folio_migrate_ksm(struct folio *newfolio, struct folio *old) #define set_pte_ksm_zero(pte) pte_mkdirty(pte_mkspecial(pte)) #define is_ksm_zero_pte(pte) (is_zero_pfn(pte_pfn(pte)) && pte_dirty(pte)) extern unsigned long ksm_zero_pages; -static inline void inc_ksm_zero_pages(void) +static inline void inc_ksm_zero_pages(struct mm_struct *mm) { ksm_zero_pages++; + mm->ksm_zero_pages++; } -static inline void dec_ksm_zero_pages(void) +static inline void dec_ksm_zero_pages(struct mm_struct *mm) { ksm_zero_pages--; + mm->ksm_zero_pages--; } #else /* !CONFIG_KSM_ZERO_PAGES_TRACK */ #define set_pte_ksm_zero(pte) pte_mkspecial(pte) #define is_ksm_zero_pte(pte) 0 -static inline void inc_ksm_zero_pages(void) +static inline void inc_ksm_zero_pages(struct mm_struct *mm) { } -static inline void dec_ksm_zero_pages(void) +static inline void dec_ksm_zero_pages(struct mm_struct *mm) { } #endif /* CONFIG_KSM_ZERO_PAGES_TRACK */ diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 3fc9e680f174..2e72329ed1a2 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -766,7 +766,7 @@ struct mm_struct { #ifdef CONFIG_KSM /* * Represent how many pages of this process are involved in KSM - * merging. + * merging (not including ksm_zero_pages). */ unsigned long ksm_merging_pages; /* @@ -774,7 +774,14 @@ struct mm_struct { * including merged and not merged. */ unsigned long ksm_rmap_items; -#endif +#ifdef CONFIG_KSM_ZERO_PAGES_TRACK + /* + * Represent how many empty pages are merged with kernel zero + * pages when enabling KSM use_zero_pages. + */ + unsigned long ksm_zero_pages; +#endif /* CONFIG_KSM_ZERO_PAGES_TRACK */ +#endif /* CONFIG_KSM */ #ifdef CONFIG_LRU_GEN struct { /* this mm_struct is on lru_gen_mm_list */ diff --git a/mm/ksm.c b/mm/ksm.c index 232680393741..7867fae3c61c 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -1248,7 +1248,7 @@ static int replace_page(struct vm_area_struct *vma, struct page *page, } else { newpte = set_pte_ksm_zero(pfn_pte(page_to_pfn(kpage), vma->vm_page_prot)); - inc_ksm_zero_pages(); + inc_ksm_zero_pages(mm); /* * We're replacing an anonymous page with a zero page, which is * not anonymous. We need to do proper accounting otherwise we diff --git a/mm/memory.c b/mm/memory.c index 76598287280f..ec89b81a14fd 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1418,7 +1418,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, ptent); if (unlikely(!page)) { if (is_ksm_zero_pte(ptent)) - dec_ksm_zero_pages(); + dec_ksm_zero_pages(mm); continue; } @@ -3122,7 +3122,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) } } else { if (is_ksm_zero_pte(vmf->orig_pte)) - dec_ksm_zero_pages(); + dec_ksm_zero_pages(mm); inc_mm_counter(mm, MM_ANONPAGES); } flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); -- 2.15.2