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 BFDF2C74A4B for ; Sun, 12 Mar 2023 20:36:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230309AbjCLUgr (ORCPT ); Sun, 12 Mar 2023 16:36:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44618 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229828AbjCLUgn (ORCPT ); Sun, 12 Mar 2023 16:36:43 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 062AB37F21 for ; Sun, 12 Mar 2023 13:36:41 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 69FB8B80C0A for ; Sun, 12 Mar 2023 20:36:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 23CC2C433D2; Sun, 12 Mar 2023 20:36:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1678653399; bh=XUwbMzDHCqGZkjlknqUYpaOOMxwgZNelh/OrB4h98Lw=; h=Date:To:From:Subject:From; b=dZzvwTk1bNBSfthenaNBBlt4rxmsd3E8fZhrO5oIDZJkbYBD+ch6xFxRi+s/mU1d/ deDb6lTD+4LRqJsLOq0mM4FxKSsJw6gBcvBGy+liX39tWJDgX8sraxONeldZHXjACL 1pfdhLtAAdvdW6Xc7BIjEocbY9/outJ4VJx4v5DI= Date: Sun, 12 Mar 2023 13:36:38 -0700 To: mm-commits@vger.kernel.org, riel@surriel.com, mhocko@suse.com, hannes@cmpxchg.org, david@redhat.com, bagasdotme@gmail.com, shr@devkernel.io, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-add-new-ksm-process-and-sysfs-knobs.patch added to mm-unstable branch Message-Id: <20230312203639.23CC2C433D2@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm: add new KSM process and sysfs knobs has been added to the -mm mm-unstable branch. Its filename is mm-add-new-ksm-process-and-sysfs-knobs.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-add-new-ksm-process-and-sysfs-knobs.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Stefan Roesch Subject: mm: add new KSM process and sysfs knobs Date: Fri, 10 Mar 2023 10:28:50 -0800 This adds the general_profit KSM sysfs knob and the process profit metric and process merge type knobs to ksm_stat. 1) split off pages_volatile function This splits off the pages_volatile function. The next patch will use this function. 2) expose general_profit metric The documentation mentions a general profit metric, however this metric is not calculated. In addition the formula depends on the size of internal structures, which makes it more difficult for an administrator to make the calculation. Adding the metric for a better user experience. 3) document general_profit sysfs knob 4) calculate ksm process profit metric The ksm documentation mentions the process profit metric and how to calculate it. This adds the calculation of the metric. 5) add ksm_merge_type() function This adds the ksm_merge_type function. The function returns the merge type for the process. For madvise it returns "madvise", for prctl it returns "process" and otherwise it returns "none". 6) mm: expose ksm process profit metric and merge type in ksm_stat This exposes the ksm process profit metric in /proc//ksm_stat. The name of the value is ksm_merge_type. The documentation mentions the formula for the ksm process profit metric, however it does not calculate it. In addition the formula depends on the size of internal structures. So it makes sense to expose it. 7) document new procfs ksm knobs Link: https://lkml.kernel.org/r/20230224044000.3084046-3-shr@devkernel.io Link: https://lkml.kernel.org/r/20230310182851.2579138-3-shr@devkernel.io Signed-off-by: Stefan Roesch Reviewed-by: Bagas Sanjaya Cc: David Hildenbrand Cc: Johannes Weiner Cc: Michal Hocko Cc: Rik van Riel Signed-off-by: Andrew Morton --- --- a/Documentation/ABI/testing/sysfs-kernel-mm-ksm~mm-add-new-ksm-process-and-sysfs-knobs +++ a/Documentation/ABI/testing/sysfs-kernel-mm-ksm @@ -51,3 +51,11 @@ Description: Control merging pages acros When it is set to 0 only pages from the same node are merged, otherwise pages from all nodes can be merged together (default). + +What: /sys/kernel/mm/ksm/general_profit +Date: January 2023 +KernelVersion: 6.1 +Contact: Linux memory management mailing list +Description: Measure how effective KSM is. + general_profit: how effective is KSM. The formula for the + calculation is in Documentation/admin-guide/mm/ksm.rst. --- a/Documentation/admin-guide/mm/ksm.rst~mm-add-new-ksm-process-and-sysfs-knobs +++ a/Documentation/admin-guide/mm/ksm.rst @@ -157,6 +157,8 @@ stable_node_chains_prune_millisecs The effectiveness of KSM and MADV_MERGEABLE is shown in ``/sys/kernel/mm/ksm/``: +general_profit + how effective is KSM. The calculation is explained below. pages_shared how many shared pages are being used pages_sharing @@ -214,7 +216,8 @@ several times, which are unprofitable me ksm_rmap_items * sizeof(rmap_item). where ksm_merging_pages is shown under the directory ``/proc//``, - and ksm_rmap_items is shown in ``/proc//ksm_stat``. + and ksm_rmap_items is shown in ``/proc//ksm_stat``. The process profit + is also shown in ``/proc//ksm_stat`` as ksm_process_profit. From the perspective of application, a high ratio of ``ksm_rmap_items`` to ``ksm_merging_pages`` means a bad madvise-applied policy, so developers or @@ -225,6 +228,9 @@ so if the ``ksm_rmap_items/ksm_merging_p or exceeds 128 on 32-bit CPU, then the app's madvise policy should be dropped, because the ksm profit is approximately zero or negative. +The ksm_merge_type in ``/proc//ksm_stat`` shows the merge type of the +process. Valid values are ``none``, ``madvise`` and ``process``. + Monitoring KSM events ===================== --- a/fs/proc/base.c~mm-add-new-ksm-process-and-sysfs-knobs +++ a/fs/proc/base.c @@ -96,6 +96,7 @@ #include #include #include +#include #include #include "internal.h" #include "fd.h" @@ -3199,6 +3200,7 @@ static int proc_pid_ksm_merging_pages(st return 0; } + static int proc_pid_ksm_stat(struct seq_file *m, struct pid_namespace *ns, struct pid *pid, struct task_struct *task) { @@ -3208,6 +3210,9 @@ static int proc_pid_ksm_stat(struct seq_ if (mm) { seq_printf(m, "ksm_rmap_items %lu\n", mm->ksm_rmap_items); seq_printf(m, "zero_pages_sharing %lu\n", mm->ksm_zero_pages_sharing); + 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)); mmput(mm); } --- a/include/linux/ksm.h~mm-add-new-ksm-process-and-sysfs-knobs +++ a/include/linux/ksm.h @@ -55,6 +55,11 @@ struct page *ksm_might_need_to_copy(stru void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc); void folio_migrate_ksm(struct folio *newfolio, struct folio *folio); +#ifdef CONFIG_PROC_FS +long ksm_process_profit(struct mm_struct *); +const char *ksm_merge_type(struct mm_struct *mm); +#endif /* CONFIG_PROC_FS */ + #else /* !CONFIG_KSM */ static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) --- a/mm/ksm.c~mm-add-new-ksm-process-and-sysfs-knobs +++ a/mm/ksm.c @@ -3031,6 +3031,25 @@ static void wait_while_offlining(void) } #endif /* CONFIG_MEMORY_HOTREMOVE */ +#ifdef CONFIG_PROC_FS +long ksm_process_profit(struct mm_struct *mm) +{ + return (long)mm->ksm_merging_pages * PAGE_SIZE - + mm->ksm_rmap_items * sizeof(struct ksm_rmap_item); +} + +/* Return merge type name as string. */ +const char *ksm_merge_type(struct mm_struct *mm) +{ + if (test_bit(MMF_VM_MERGE_ANY, &mm->flags)) + return "process"; + else if (test_bit(MMF_VM_MERGEABLE, &mm->flags)) + return "madvise"; + else + return "none"; +} +#endif /* CONFIG_PROC_FS */ + #ifdef CONFIG_SYSFS /* * This all compiles without CONFIG_SYSFS, but is a waste of space. @@ -3278,8 +3297,7 @@ static ssize_t pages_unshared_show(struc } KSM_ATTR_RO(pages_unshared); -static ssize_t pages_volatile_show(struct kobject *kobj, - struct kobj_attribute *attr, char *buf) +static long pages_volatile(void) { long ksm_pages_volatile; @@ -3291,7 +3309,14 @@ static ssize_t pages_volatile_show(struc */ if (ksm_pages_volatile < 0) ksm_pages_volatile = 0; - return sysfs_emit(buf, "%ld\n", ksm_pages_volatile); + + return ksm_pages_volatile; +} + +static ssize_t pages_volatile_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%ld\n", pages_volatile()); } KSM_ATTR_RO(pages_volatile); @@ -3302,6 +3327,21 @@ static ssize_t zero_pages_sharing_show(s } KSM_ATTR_RO(zero_pages_sharing); +static ssize_t general_profit_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + long general_profit; + long all_rmap_items; + + all_rmap_items = ksm_max_page_sharing + ksm_pages_shared + + ksm_pages_unshared + pages_volatile(); + general_profit = ksm_pages_sharing * PAGE_SIZE - + all_rmap_items * sizeof(struct ksm_rmap_item); + + return sysfs_emit(buf, "%ld\n", general_profit); +} +KSM_ATTR_RO(general_profit); + static ssize_t stable_node_dups_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { @@ -3367,6 +3407,7 @@ static struct attribute *ksm_attrs[] = { &stable_node_dups_attr.attr, &stable_node_chains_prune_millisecs_attr.attr, &use_zero_pages_attr.attr, + &general_profit_attr.attr, NULL, }; _ Patches currently in -mm which might be from shr@devkernel.io are mm-add-tracepoints-to-ksm.patch mm-add-new-api-to-enable-ksm-per-process.patch mm-add-new-ksm-process-and-sysfs-knobs.patch selftests-mm-add-new-selftests-for-ksm.patch