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[2620:137:e000::1:20]) by mx.google.com with ESMTP id f7-20020a170902684700b001b88dbc8b09si7981905pln.454.2023.07.31.16.56.39; Mon, 31 Jul 2023 16:56:51 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230459AbjGaXSZ (ORCPT + 99 others); Mon, 31 Jul 2023 19:18:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40412 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229845AbjGaXRg (ORCPT ); Mon, 31 Jul 2023 19:17:36 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B57F1FEB for ; Mon, 31 Jul 2023 16:17:22 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 812CA61360 for ; Mon, 31 Jul 2023 23:17:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DAE1CC433CC; Mon, 31 Jul 2023 23:17:08 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.96) (envelope-from ) id 1qQc8R-003fRa-2y; Mon, 31 Jul 2023 19:17:07 -0400 Message-ID: <20230731231707.741705134@goodmis.org> User-Agent: quilt/0.66 Date: Mon, 31 Jul 2023 19:16:48 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Andrew Morton , Ajay Kaher , Ching-lin Yu Subject: [for-next][PATCH 14/15] eventfs: Move tracing/events to eventfs References: <20230731231634.031452225@goodmis.org> MIME-Version: 1.0 X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1772982435143243363 X-GMAIL-MSGID: 1772982435143243363 From: Ajay Kaher Up until now, /sys/kernel/tracing/events was no different than any other part of tracefs. The files and directories within the events directory was created when the tracefs was mounted, and also created for the instances in /sys/kernel/tracing/instances//events. Most of these files and directories will never be referenced. Since there are thousands of these files and directories they spend their time wasting precious memory resources. Move the "events" directory to the new eventfs. The eventfs will take the meta data of the events that they represent and store that. When the files in the events directory are referenced, the dentry and inodes to represent them are then created. When the files are no longer referenced, they are freed. This saves the precious memory resources that were wasted on these seldom referenced dentries and inodes. Running the following: ~# cat /proc/meminfo /proc/slabinfo > before.out ~# mkdir /sys/kernel/tracing/instances/foo ~# cat /proc/meminfo /proc/slabinfo > after.out to test the changes produces the following deltas: Before this change: Before after deltas for meminfo: MemFree: -32260 MemAvailable: -21496 KReclaimable: 21528 Slab: 22440 SReclaimable: 21528 SUnreclaim: 912 VmallocUsed: 16 Before after deltas for slabinfo: : [ * = ] tracefs_inode_cache: 14472 [* 1184 = 17134848] buffer_head: 24 [* 168 = 4032] hmem_inode_cache: 28 [* 1480 = 41440] dentry: 14450 [* 312 = 4508400] lsm_inode_cache: 14453 [* 32 = 462496] vma_lock: 11 [* 152 = 1672] vm_area_struct: 2 [* 184 = 368] trace_event_file: 1748 [* 88 = 153824] kmalloc-256: 1072 [* 256 = 274432] kmalloc-64: 2842 [* 64 = 181888] Total slab additions in size: 22,763,400 bytes With this change: Before after deltas for meminfo: MemFree: -12600 MemAvailable: -12580 Cached: 24 Active: 12 Inactive: 68 Inactive(anon): 48 Active(file): 12 Inactive(file): 20 Dirty: -4 AnonPages: 68 KReclaimable: 12 Slab: 1856 SReclaimable: 12 SUnreclaim: 1844 KernelStack: 16 PageTables: 36 VmallocUsed: 16 Before after deltas for slabinfo: : [ * = ] tracefs_inode_cache: 108 [* 1184 = 127872] buffer_head: 24 [* 168 = 4032] hmem_inode_cache: 18 [* 1480 = 26640] dentry: 127 [* 312 = 39624] lsm_inode_cache: 152 [* 32 = 4864] vma_lock: 67 [* 152 = 10184] vm_area_struct: -12 [* 184 = -2208] trace_event_file: 1764 [* 96 = 169344] kmalloc-96: 14322 [* 96 = 1374912] kmalloc-64: 2814 [* 64 = 180096] kmalloc-32: 1103 [* 32 = 35296] kmalloc-16: 2308 [* 16 = 36928] kmalloc-8: 12800 [* 8 = 102400] Total slab additions in size: 2,109,984 bytes Which is a savings of 20,653,416 bytes (20 MB) per tracing instance. Link: https://lkml.kernel.org/r/1690568452-46553-10-git-send-email-akaher@vmware.com Signed-off-by: Ajay Kaher Co-developed-by: Steven Rostedt (VMware) Signed-off-by: Steven Rostedt (VMware) Tested-by: Ching-lin Yu Signed-off-by: Steven Rostedt (Google) --- fs/tracefs/inode.c | 18 ++++++++++ include/linux/trace_events.h | 1 + kernel/trace/trace.h | 2 +- kernel/trace/trace_events.c | 65 ++++++++++++++++++------------------ 4 files changed, 53 insertions(+), 33 deletions(-) diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c index d9273066f25f..bb6de89eb446 100644 --- a/fs/tracefs/inode.c +++ b/fs/tracefs/inode.c @@ -374,6 +374,23 @@ static const struct super_operations tracefs_super_operations = { .show_options = tracefs_show_options, }; +static void tracefs_dentry_iput(struct dentry *dentry, struct inode *inode) +{ + struct tracefs_inode *ti; + + if (!dentry || !inode) + return; + + ti = get_tracefs(inode); + if (ti && ti->flags & TRACEFS_EVENT_INODE) + eventfs_set_ef_status_free(dentry); + iput(inode); +} + +static const struct dentry_operations tracefs_dentry_operations = { + .d_iput = tracefs_dentry_iput, +}; + static int trace_fill_super(struct super_block *sb, void *data, int silent) { static const struct tree_descr trace_files[] = {{""}}; @@ -396,6 +413,7 @@ static int trace_fill_super(struct super_block *sb, void *data, int silent) goto fail; sb->s_op = &tracefs_super_operations; + sb->s_d_op = &tracefs_dentry_operations; tracefs_apply_options(sb, false); diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 3930e676436c..c17623c78029 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -638,6 +638,7 @@ struct trace_event_file { struct list_head list; struct trace_event_call *event_call; struct event_filter __rcu *filter; + struct eventfs_file *ef; struct dentry *dir; struct trace_array *tr; struct trace_subsystem_dir *system; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index ba7ababb8308..5b1f9e24764a 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1334,7 +1334,7 @@ struct trace_subsystem_dir { struct list_head list; struct event_subsystem *subsystem; struct trace_array *tr; - struct dentry *entry; + struct eventfs_file *ef; int ref_count; int nr_events; }; diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 3ecc41f6acd9..ed367d713be0 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -984,7 +984,7 @@ static void remove_subsystem(struct trace_subsystem_dir *dir) return; if (!--dir->nr_events) { - tracefs_remove(dir->entry); + eventfs_remove(dir->ef); list_del(&dir->list); __put_system_dir(dir); } @@ -1005,7 +1005,7 @@ static void remove_event_file_dir(struct trace_event_file *file) tracefs_remove(dir); } - + eventfs_remove(file->ef); list_del(&file->list); remove_subsystem(file->system); free_event_filter(file->filter); @@ -2291,13 +2291,13 @@ create_new_subsystem(const char *name) return NULL; } -static struct dentry * +static struct eventfs_file * event_subsystem_dir(struct trace_array *tr, const char *name, struct trace_event_file *file, struct dentry *parent) { struct event_subsystem *system, *iter; struct trace_subsystem_dir *dir; - struct dentry *entry; + int res; /* First see if we did not already create this dir */ list_for_each_entry(dir, &tr->systems, list) { @@ -2305,7 +2305,7 @@ event_subsystem_dir(struct trace_array *tr, const char *name, if (strcmp(system->name, name) == 0) { dir->nr_events++; file->system = dir; - return dir->entry; + return dir->ef; } } @@ -2329,8 +2329,8 @@ event_subsystem_dir(struct trace_array *tr, const char *name, } else __get_system(system); - dir->entry = tracefs_create_dir(name, parent); - if (!dir->entry) { + dir->ef = eventfs_add_subsystem_dir(name, parent); + if (IS_ERR(dir->ef)) { pr_warn("Failed to create system directory %s\n", name); __put_system(system); goto out_free; @@ -2345,22 +2345,22 @@ event_subsystem_dir(struct trace_array *tr, const char *name, /* the ftrace system is special, do not create enable or filter files */ if (strcmp(name, "ftrace") != 0) { - entry = tracefs_create_file("filter", TRACE_MODE_WRITE, - dir->entry, dir, + res = eventfs_add_file("filter", TRACE_MODE_WRITE, + dir->ef, dir, &ftrace_subsystem_filter_fops); - if (!entry) { + if (res) { kfree(system->filter); system->filter = NULL; pr_warn("Could not create tracefs '%s/filter' entry\n", name); } - trace_create_file("enable", TRACE_MODE_WRITE, dir->entry, dir, + eventfs_add_file("enable", TRACE_MODE_WRITE, dir->ef, dir, &ftrace_system_enable_fops); } list_add(&dir->list, &tr->systems); - return dir->entry; + return dir->ef; out_free: kfree(dir); @@ -2413,8 +2413,8 @@ static int event_create_dir(struct dentry *parent, struct trace_event_file *file) { struct trace_event_call *call = file->event_call; + struct eventfs_file *ef_subsystem = NULL; struct trace_array *tr = file->tr; - struct dentry *d_events; const char *name; int ret; @@ -2426,24 +2426,24 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file) if (WARN_ON_ONCE(strcmp(call->class->system, TRACE_SYSTEM) == 0)) return -ENODEV; - d_events = event_subsystem_dir(tr, call->class->system, file, parent); - if (!d_events) + ef_subsystem = event_subsystem_dir(tr, call->class->system, file, parent); + if (!ef_subsystem) return -ENOMEM; name = trace_event_name(call); - file->dir = tracefs_create_dir(name, d_events); - if (!file->dir) { + file->ef = eventfs_add_dir(name, ef_subsystem); + if (IS_ERR(file->ef)) { pr_warn("Could not create tracefs '%s' directory\n", name); return -1; } if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) - trace_create_file("enable", TRACE_MODE_WRITE, file->dir, file, + eventfs_add_file("enable", TRACE_MODE_WRITE, file->ef, file, &ftrace_enable_fops); #ifdef CONFIG_PERF_EVENTS if (call->event.type && call->class->reg) - trace_create_file("id", TRACE_MODE_READ, file->dir, + eventfs_add_file("id", TRACE_MODE_READ, file->ef, (void *)(long)call->event.type, &ftrace_event_id_fops); #endif @@ -2459,27 +2459,27 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file) * triggers or filters. */ if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) { - trace_create_file("filter", TRACE_MODE_WRITE, file->dir, + eventfs_add_file("filter", TRACE_MODE_WRITE, file->ef, file, &ftrace_event_filter_fops); - trace_create_file("trigger", TRACE_MODE_WRITE, file->dir, + eventfs_add_file("trigger", TRACE_MODE_WRITE, file->ef, file, &event_trigger_fops); } #ifdef CONFIG_HIST_TRIGGERS - trace_create_file("hist", TRACE_MODE_READ, file->dir, file, + eventfs_add_file("hist", TRACE_MODE_READ, file->ef, file, &event_hist_fops); #endif #ifdef CONFIG_HIST_TRIGGERS_DEBUG - trace_create_file("hist_debug", TRACE_MODE_READ, file->dir, file, + eventfs_add_file("hist_debug", TRACE_MODE_READ, file->ef, file, &event_hist_debug_fops); #endif - trace_create_file("format", TRACE_MODE_READ, file->dir, call, + eventfs_add_file("format", TRACE_MODE_READ, file->ef, call, &ftrace_event_format_fops); #ifdef CONFIG_TRACE_EVENT_INJECT if (call->event.type && call->class->reg) - trace_create_file("inject", 0200, file->dir, file, + eventfs_add_file("inject", 0200, file->ef, file, &event_inject_fops); #endif @@ -3632,21 +3632,22 @@ create_event_toplevel_files(struct dentry *parent, struct trace_array *tr) { struct dentry *d_events; struct dentry *entry; + int error = 0; entry = trace_create_file("set_event", TRACE_MODE_WRITE, parent, tr, &ftrace_set_event_fops); if (!entry) return -ENOMEM; - d_events = tracefs_create_dir("events", parent); - if (!d_events) { + d_events = eventfs_create_events_dir("events", parent); + if (IS_ERR(d_events)) { pr_warn("Could not create tracefs 'events' directory\n"); return -ENOMEM; } - entry = trace_create_file("enable", TRACE_MODE_WRITE, d_events, + error = eventfs_add_events_file("enable", TRACE_MODE_WRITE, d_events, tr, &ftrace_tr_enable_fops); - if (!entry) + if (error) return -ENOMEM; /* There are not as crucial, just warn if they are not created */ @@ -3659,11 +3660,11 @@ create_event_toplevel_files(struct dentry *parent, struct trace_array *tr) &ftrace_set_event_notrace_pid_fops); /* ring buffer internal formats */ - trace_create_file("header_page", TRACE_MODE_READ, d_events, + eventfs_add_events_file("header_page", TRACE_MODE_READ, d_events, ring_buffer_print_page_header, &ftrace_show_header_fops); - trace_create_file("header_event", TRACE_MODE_READ, d_events, + eventfs_add_events_file("header_event", TRACE_MODE_READ, d_events, ring_buffer_print_entry_header, &ftrace_show_header_fops); @@ -3751,7 +3752,7 @@ int event_trace_del_tracer(struct trace_array *tr) down_write(&trace_event_sem); __trace_remove_event_dirs(tr); - tracefs_remove(tr->event_dir); + eventfs_remove_events_dir(tr->event_dir); up_write(&trace_event_sem); tr->event_dir = NULL;