From nobody Thu Sep 18 12:54:50 2025 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 0EC1CC63706 for ; Tue, 6 Dec 2022 15:51:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234372AbiLFPvD (ORCPT ); Tue, 6 Dec 2022 10:51:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39492 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234618AbiLFPuo (ORCPT ); Tue, 6 Dec 2022 10:50:44 -0500 X-Greylist: delayed 527 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Tue, 06 Dec 2022 07:50:37 PST Received: from mailout.easymail.ca (mailout.easymail.ca [64.68.200.34]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DFA702DA90; Tue, 6 Dec 2022 07:50:37 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by mailout.easymail.ca (Postfix) with ESMTP id A0B62E74B3; Tue, 6 Dec 2022 15:41:50 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at emo08-pco.easydns.vpn Received: from mailout.easymail.ca ([127.0.0.1]) by localhost (emo08-pco.easydns.vpn [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id o6MELZ_AxPs3; Tue, 6 Dec 2022 15:41:50 +0000 (UTC) Received: from mail.gonehiking.org (unknown [38.15.45.1]) by mailout.easymail.ca (Postfix) with ESMTPA id 43637E7494; Tue, 6 Dec 2022 15:41:50 +0000 (UTC) Received: from localhost.localdomain (internal [192.168.1.4]) by mail.gonehiking.org (Postfix) with ESMTP id 877713EEF7; Tue, 6 Dec 2022 08:41:48 -0700 (MST) From: Khalid Aziz To: akpm@linux-foundation.org, willy@infradead.org, djwong@kernel.org, markhemm@googlemail.com, viro@zeniv.linux.org.uk, david@redhat.com, mike.kravetz@oracle.com Cc: Khalid Aziz , andreyknvl@gmail.com, dave.hansen@intel.com, luto@kernel.org, 21cnbao@gmail.com, arnd@arndb.de, ebiederm@xmission.com, elver@google.com, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhiramat@kernel.org, rostedt@goodmis.org, vasily.averin@linux.dev, Khalid Aziz Subject: [RFC PATCH 1/2] mm/ptshare: Add vm flag for shared PTE Date: Tue, 6 Dec 2022 08:41:40 -0700 Message-Id: X-Mailer: git-send-email 2.34.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Add a bit to vm_flags to indicate a vma shares PTEs with others. Add a function to determine if a vma shares PTE by checking this flag. This is to be used to find the shared page table entries on page fault for vmas sharing PTE. Signed-off-by: Khalid Aziz Signed-off-by: Matthew Wilcox (Oracle) --- include/linux/mm.h | 8 ++++++++ include/trace/events/mmflags.h | 3 ++- mm/internal.h | 5 +++++ 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 8bbcccbc5565..699323be7502 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -314,11 +314,13 @@ extern unsigned int kobjsize(const void *objp); #define VM_HIGH_ARCH_BIT_2 34 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_BIT_3 35 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_BIT_4 36 /* bit only usable on 64-bit architectures */ +#define VM_HIGH_ARCH_BIT_5 37 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_0 BIT(VM_HIGH_ARCH_BIT_0) #define VM_HIGH_ARCH_1 BIT(VM_HIGH_ARCH_BIT_1) #define VM_HIGH_ARCH_2 BIT(VM_HIGH_ARCH_BIT_2) #define VM_HIGH_ARCH_3 BIT(VM_HIGH_ARCH_BIT_3) #define VM_HIGH_ARCH_4 BIT(VM_HIGH_ARCH_BIT_4) +#define VM_HIGH_ARCH_5 BIT(VM_HIGH_ARCH_BIT_5) #endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */ =20 #ifdef CONFIG_ARCH_HAS_PKEYS @@ -360,6 +362,12 @@ extern unsigned int kobjsize(const void *objp); # define VM_MTE_ALLOWED VM_NONE #endif =20 +#ifdef CONFIG_ARCH_USES_HIGH_VMA_FLAGS +#define VM_SHARED_PT VM_HIGH_ARCH_5 +#else +#define VM_SHARED_PT VM_NONE +#endif + #ifndef VM_GROWSUP # define VM_GROWSUP VM_NONE #endif diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h index e87cb2b80ed3..30e56cbac99b 100644 --- a/include/trace/events/mmflags.h +++ b/include/trace/events/mmflags.h @@ -194,7 +194,8 @@ IF_HAVE_VM_SOFTDIRTY(VM_SOFTDIRTY, "softdirty" ) \ {VM_MIXEDMAP, "mixedmap" }, \ {VM_HUGEPAGE, "hugepage" }, \ {VM_NOHUGEPAGE, "nohugepage" }, \ - {VM_MERGEABLE, "mergeable" } \ + {VM_MERGEABLE, "mergeable" }, \ + {VM_SHARED_PT, "sharedpt" } \ =20 #define show_vma_flags(flags) \ (flags) ? __print_flags(flags, "|", \ diff --git a/mm/internal.h b/mm/internal.h index 6b7ef495b56d..16083eca720e 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -856,4 +856,9 @@ static inline bool vma_soft_dirty_enabled(struct vm_are= a_struct *vma) return !(vma->vm_flags & VM_SOFTDIRTY); } =20 +static inline bool vma_is_shared(const struct vm_area_struct *vma) +{ + return vma->vm_flags & VM_SHARED_PT; +} + #endif /* __MM_INTERNAL_H */ --=20 2.34.1