From patchwork Mon Jan 23 17:37:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13112710 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 94A02C54EAA for ; Mon, 23 Jan 2023 18:05:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233706AbjAWSFJ (ORCPT ); Mon, 23 Jan 2023 13:05:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233100AbjAWSFE (ORCPT ); Mon, 23 Jan 2023 13:05:04 -0500 Received: from 66-220-144-178.mail-mxout.facebook.com (66-220-144-178.mail-mxout.facebook.com [66.220.144.178]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D9083303D7 for ; Mon, 23 Jan 2023 10:05:03 -0800 (PST) Received: by dev0134.prn3.facebook.com (Postfix, from userid 425415) id 572115616BDD; Mon, 23 Jan 2023 09:37:56 -0800 (PST) From: Stefan Roesch To: linux-mm@kvack.org Cc: shr@devkernel.io, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [RESEND RFC PATCH v1 06/20] mm: add new prctl option to get and set ksm for a process Date: Mon, 23 Jan 2023 09:37:34 -0800 Message-Id: <20230123173748.1734238-7-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230123173748.1734238-1-shr@devkernel.io> References: <20230123173748.1734238-1-shr@devkernel.io> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org This adds two new options to the prctl system call - enable ksm for all vmas of a process (if the vmas support it). - query if ksm has been enabled for a process. Signed-off-by: Stefan Roesch --- include/uapi/linux/prctl.h | 2 ++ kernel/sys.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 31 insertions(+) diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index a5e06dcbba13..b8ba85f18e43 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -284,4 +284,6 @@ struct prctl_mm_map { #define PR_SET_VMA 0x53564d41 # define PR_SET_VMA_ANON_NAME 0 +#define PR_SET_MEMORY_MERGE 65 +#define PR_GET_MEMORY_MERGE 66 #endif /* _LINUX_PRCTL_H */ diff --git a/kernel/sys.c b/kernel/sys.c index 5fd54bf0e886..de218e3b6f42 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -2626,6 +2627,34 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, case PR_SET_VMA: error = prctl_set_vma(arg2, arg3, arg4, arg5); break; +#ifdef CONFIG_KSM + case PR_SET_MEMORY_MERGE: + if (!capable(CAP_SYS_RESOURCE)) + return -EPERM; + + if (arg2) { + if (mmap_write_lock_killable(me->mm)) + return -EINTR; + + if (test_bit(MMF_VM_MERGEABLE, &me->mm->flags)) + error = -EINVAL; + else if (!test_bit(MMF_VM_MERGE_ANY, &me->mm->flags)) + error = __ksm_enter(me->mm, MMF_VM_MERGE_ANY); + mmap_write_unlock(me->mm); + } else { + __ksm_exit(me->mm, MMF_VM_MERGE_ANY); + } + break; + case PR_GET_MEMORY_MERGE: + if (!capable(CAP_SYS_RESOURCE)) + return -EPERM; + + if (arg2 || arg3 || arg4 || arg5) + return -EINVAL; + + error = !!test_bit(MMF_VM_MERGE_ANY, &me->mm->flags); + break; +#endif default: error = -EINVAL; break;