From d23569979ca1cd139a42c410e0c7b9e6014c3b3a Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" Date: Wed, 13 Dec 2023 09:37:01 -0500 Subject: tracing: Allow creating instances with specified system events A trace instance may only need to enable specific events. As the eventfs directory of an instance currently creates all events which adds overhead, allow internal instances to be created with just the events in systems that they care about. This currently only deals with systems and not individual events, but this should bring down the overhead of creating instances for specific use cases quite bit. The trace_array_get_by_name() now has another parameter "systems". This parameter is a const string pointer of a comma/space separated list of event systems that should be created by the trace_array. (Note if the trace_array already exists, this parameter is ignored). The list of systems is saved and if a module is loaded, its events will not be added unless the system for those events also match the systems string. Link: https://lore.kernel.org/linux-trace-kernel/20231213093701.03fddec0@gandalf.local.home Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Sean Paul Cc: Arun Easi Cc: Daniel Wagner Tested-by: Dmytro Maluka Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace.h | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/trace/trace.h') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 0489e72c8169..79180aed13ee 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -377,6 +377,7 @@ struct trace_array { unsigned char trace_flags_index[TRACE_FLAGS_MAX_SIZE]; unsigned int flags; raw_spinlock_t start_lock; + const char *system_names; struct list_head err_log; struct dentry *dir; struct dentry *options; -- cgit v1.2.3 From 139f84002145d8624f0195fb090b3a7670744a13 Mon Sep 17 00:00:00 2001 From: "Tzvetomir Stoyanov (VMware)" Date: Tue, 19 Dec 2023 13:54:16 -0500 Subject: ring-buffer: Page size per ring buffer Currently the size of one sub buffer page is global for all buffers and it is hard coded to one system page. In order to introduce configurable ring buffer sub page size, the internal logic should be refactored to work with sub page size per ring buffer. Link: https://lore.kernel.org/linux-trace-devel/20211213094825.61876-3-tz.stoyanov@gmail.com Link: https://lore.kernel.org/linux-trace-kernel/20231219185628.009147038@goodmis.org Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Andrew Morton Cc: Vincent Donnefort Cc: Kent Overstreet Signed-off-by: Tzvetomir Stoyanov (VMware) Signed-off-by: Steven Rostedt (Google) --- include/linux/ring_buffer.h | 2 +- kernel/trace/ring_buffer.c | 68 +++++++++++++++++++++++++-------------------- kernel/trace/trace.c | 2 +- kernel/trace/trace.h | 1 + kernel/trace/trace_events.c | 59 +++++++++++++++++++++++++++++---------- 5 files changed, 86 insertions(+), 46 deletions(-) (limited to 'kernel/trace/trace.h') diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h index b1b03b2c0f08..ce46218ce46d 100644 --- a/include/linux/ring_buffer.h +++ b/include/linux/ring_buffer.h @@ -200,7 +200,7 @@ int ring_buffer_read_page(struct trace_buffer *buffer, void **data_page, struct trace_seq; int ring_buffer_print_entry_header(struct trace_seq *s); -int ring_buffer_print_page_header(struct trace_seq *s); +int ring_buffer_print_page_header(struct trace_buffer *buffer, struct trace_seq *s); enum ring_buffer_flags { RB_FL_OVERWRITE = 1 << 0, diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 2400c8e68fd3..d9f656502400 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -374,11 +374,6 @@ static inline bool test_time_stamp(u64 delta) return !!(delta & TS_DELTA_TEST); } -#define BUF_PAGE_SIZE (PAGE_SIZE - BUF_PAGE_HDR_SIZE) - -/* Max payload is BUF_PAGE_SIZE - header (8bytes) */ -#define BUF_MAX_DATA_SIZE (BUF_PAGE_SIZE - (sizeof(u32) * 2)) - struct rb_irq_work { struct irq_work work; wait_queue_head_t waiters; @@ -510,6 +505,9 @@ struct trace_buffer { struct rb_irq_work irq_work; bool time_stamp_abs; + + unsigned int subbuf_size; + unsigned int max_data_size; }; struct ring_buffer_iter { @@ -523,10 +521,11 @@ struct ring_buffer_iter { u64 read_stamp; u64 page_stamp; struct ring_buffer_event *event; + size_t event_size; int missed_events; }; -int ring_buffer_print_page_header(struct trace_seq *s) +int ring_buffer_print_page_header(struct trace_buffer *buffer, struct trace_seq *s) { struct buffer_data_page field; @@ -550,7 +549,7 @@ int ring_buffer_print_page_header(struct trace_seq *s) trace_seq_printf(s, "\tfield: char data;\t" "offset:%u;\tsize:%u;\tsigned:%u;\n", (unsigned int)offsetof(typeof(field), data), - (unsigned int)BUF_PAGE_SIZE, + (unsigned int)buffer->subbuf_size, (unsigned int)is_signed_type(char)); return !trace_seq_has_overflowed(s); @@ -1625,7 +1624,13 @@ struct trace_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags, if (!zalloc_cpumask_var(&buffer->cpumask, GFP_KERNEL)) goto fail_free_buffer; - nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE); + /* Default buffer page size - one system page */ + buffer->subbuf_size = PAGE_SIZE - BUF_PAGE_HDR_SIZE; + + /* Max payload is buffer page size - header (8bytes) */ + buffer->max_data_size = buffer->subbuf_size - (sizeof(u32) * 2); + + nr_pages = DIV_ROUND_UP(size, buffer->subbuf_size); buffer->flags = flags; buffer->clock = trace_clock_local; buffer->reader_lock_key = key; @@ -1944,7 +1949,7 @@ static void update_pages_handler(struct work_struct *work) * @size: the new size. * @cpu_id: the cpu buffer to resize * - * Minimum size is 2 * BUF_PAGE_SIZE. + * Minimum size is 2 * buffer->subbuf_size. * * Returns 0 on success and < 0 on failure. */ @@ -1966,7 +1971,7 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, !cpumask_test_cpu(cpu_id, buffer->cpumask)) return 0; - nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE); + nr_pages = DIV_ROUND_UP(size, buffer->subbuf_size); /* we need a minimum of two pages */ if (nr_pages < 2) @@ -2213,7 +2218,7 @@ rb_iter_head_event(struct ring_buffer_iter *iter) */ barrier(); - if ((iter->head + length) > commit || length > BUF_PAGE_SIZE) + if ((iter->head + length) > commit || length > iter->event_size) /* Writer corrupted the read? */ goto reset; @@ -2446,6 +2451,7 @@ static inline void rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer, unsigned long tail, struct rb_event_info *info) { + unsigned long bsize = READ_ONCE(cpu_buffer->buffer->subbuf_size); struct buffer_page *tail_page = info->tail_page; struct ring_buffer_event *event; unsigned long length = info->length; @@ -2454,13 +2460,13 @@ rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer, * Only the event that crossed the page boundary * must fill the old tail_page with padding. */ - if (tail >= BUF_PAGE_SIZE) { + if (tail >= bsize) { /* * If the page was filled, then we still need * to update the real_end. Reset it to zero * and the reader will ignore it. */ - if (tail == BUF_PAGE_SIZE) + if (tail == bsize) tail_page->real_end = 0; local_sub(length, &tail_page->write); @@ -2488,7 +2494,7 @@ rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer, * If we are less than the minimum size, we don't need to * worry about it. */ - if (tail > (BUF_PAGE_SIZE - RB_EVNT_MIN_SIZE)) { + if (tail > (bsize - RB_EVNT_MIN_SIZE)) { /* No room for any events */ /* Mark the rest of the page with padding */ @@ -2503,19 +2509,19 @@ rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer, } /* Put in a discarded event */ - event->array[0] = (BUF_PAGE_SIZE - tail) - RB_EVNT_HDR_SIZE; + event->array[0] = (bsize - tail) - RB_EVNT_HDR_SIZE; event->type_len = RINGBUF_TYPE_PADDING; /* time delta must be non zero */ event->time_delta = 1; /* account for padding bytes */ - local_add(BUF_PAGE_SIZE - tail, &cpu_buffer->entries_bytes); + local_add(bsize - tail, &cpu_buffer->entries_bytes); /* Make sure the padding is visible before the tail_page->write update */ smp_wmb(); /* Set write to end of buffer */ - length = (tail + length) - BUF_PAGE_SIZE; + length = (tail + length) - bsize; local_sub(length, &tail_page->write); } @@ -3469,7 +3475,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, tail = write - info->length; /* See if we shot pass the end of this buffer page */ - if (unlikely(write > BUF_PAGE_SIZE)) { + if (unlikely(write > cpu_buffer->buffer->subbuf_size)) { check_buffer(cpu_buffer, info, CHECK_FULL_PAGE); return rb_move_tail(cpu_buffer, tail, info); } @@ -3600,7 +3606,7 @@ rb_reserve_next_event(struct trace_buffer *buffer, if (ring_buffer_time_stamp_abs(cpu_buffer->buffer)) { add_ts_default = RB_ADD_STAMP_ABSOLUTE; info.length += RB_LEN_TIME_EXTEND; - if (info.length > BUF_MAX_DATA_SIZE) + if (info.length > cpu_buffer->buffer->max_data_size) goto out_fail; } else { add_ts_default = RB_ADD_STAMP_NONE; @@ -3675,7 +3681,7 @@ ring_buffer_lock_reserve(struct trace_buffer *buffer, unsigned long length) if (unlikely(atomic_read(&cpu_buffer->record_disabled))) goto out; - if (unlikely(length > BUF_MAX_DATA_SIZE)) + if (unlikely(length > buffer->max_data_size)) goto out; if (unlikely(trace_recursive_lock(cpu_buffer))) @@ -3825,7 +3831,7 @@ int ring_buffer_write(struct trace_buffer *buffer, if (atomic_read(&cpu_buffer->record_disabled)) goto out; - if (length > BUF_MAX_DATA_SIZE) + if (length > buffer->max_data_size) goto out; if (unlikely(trace_recursive_lock(cpu_buffer))) @@ -4405,6 +4411,7 @@ static struct buffer_page * rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer) { struct buffer_page *reader = NULL; + unsigned long bsize = READ_ONCE(cpu_buffer->buffer->subbuf_size); unsigned long overwrite; unsigned long flags; int nr_loops = 0; @@ -4540,7 +4547,7 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer) #define USECS_WAIT 1000000 for (nr_loops = 0; nr_loops < USECS_WAIT; nr_loops++) { /* If the write is past the end of page, a writer is still updating it */ - if (likely(!reader || rb_page_write(reader) <= BUF_PAGE_SIZE)) + if (likely(!reader || rb_page_write(reader) <= bsize)) break; udelay(1); @@ -4984,7 +4991,8 @@ ring_buffer_read_prepare(struct trace_buffer *buffer, int cpu, gfp_t flags) return NULL; /* Holds the entire event: data and meta data */ - iter->event = kmalloc(BUF_PAGE_SIZE, flags); + iter->event_size = buffer->subbuf_size; + iter->event = kmalloc(iter->event_size, flags); if (!iter->event) { kfree(iter); return NULL; @@ -5102,14 +5110,14 @@ unsigned long ring_buffer_size(struct trace_buffer *buffer, int cpu) { /* * Earlier, this method returned - * BUF_PAGE_SIZE * buffer->nr_pages + * buffer->subbuf_size * buffer->nr_pages * Since the nr_pages field is now removed, we have converted this to * return the per cpu buffer value. */ if (!cpumask_test_cpu(cpu, buffer->cpumask)) return 0; - return BUF_PAGE_SIZE * buffer->buffers[cpu]->nr_pages; + return buffer->subbuf_size * buffer->buffers[cpu]->nr_pages; } EXPORT_SYMBOL_GPL(ring_buffer_size); @@ -5123,8 +5131,8 @@ unsigned long ring_buffer_max_event_size(struct trace_buffer *buffer) { /* If abs timestamp is requested, events have a timestamp too */ if (ring_buffer_time_stamp_abs(buffer)) - return BUF_MAX_DATA_SIZE - RB_LEN_TIME_EXTEND; - return BUF_MAX_DATA_SIZE; + return buffer->max_data_size - RB_LEN_TIME_EXTEND; + return buffer->max_data_size; } EXPORT_SYMBOL_GPL(ring_buffer_max_event_size); @@ -5730,7 +5738,7 @@ int ring_buffer_read_page(struct trace_buffer *buffer, /* If there is room at the end of the page to save the * missed events, then record it there. */ - if (BUF_PAGE_SIZE - commit >= sizeof(missed_events)) { + if (buffer->subbuf_size - commit >= sizeof(missed_events)) { memcpy(&bpage->data[commit], &missed_events, sizeof(missed_events)); local_add(RB_MISSED_STORED, &bpage->commit); @@ -5742,8 +5750,8 @@ int ring_buffer_read_page(struct trace_buffer *buffer, /* * This page may be off to user land. Zero it out here. */ - if (commit < BUF_PAGE_SIZE) - memset(&bpage->data[commit], 0, BUF_PAGE_SIZE - commit); + if (commit < buffer->subbuf_size) + memset(&bpage->data[commit], 0, buffer->subbuf_size - commit); out_unlock: raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 55dabee4c78b..76dd0a4c8cb5 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5018,7 +5018,7 @@ static int tracing_release(struct inode *inode, struct file *file) return 0; } -static int tracing_release_generic_tr(struct inode *inode, struct file *file) +int tracing_release_generic_tr(struct inode *inode, struct file *file) { struct trace_array *tr = inode->i_private; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 79180aed13ee..00f873910c5d 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -616,6 +616,7 @@ void tracing_reset_all_online_cpus(void); void tracing_reset_all_online_cpus_unlocked(void); int tracing_open_generic(struct inode *inode, struct file *filp); int tracing_open_generic_tr(struct inode *inode, struct file *filp); +int tracing_release_generic_tr(struct inode *inode, struct file *file); int tracing_open_file_tr(struct inode *inode, struct file *filp); int tracing_release_file_tr(struct inode *inode, struct file *filp); int tracing_single_release_file_tr(struct inode *inode, struct file *filp); diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index b70d03818038..7c364b87352e 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1893,9 +1893,9 @@ subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt, } static ssize_t -show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) +show_header_page_file(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { - int (*func)(struct trace_seq *s) = filp->private_data; + struct trace_array *tr = filp->private_data; struct trace_seq *s; int r; @@ -1908,7 +1908,31 @@ show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) trace_seq_init(s); - func(s); + ring_buffer_print_page_header(tr->array_buffer.buffer, s); + r = simple_read_from_buffer(ubuf, cnt, ppos, + s->buffer, trace_seq_used(s)); + + kfree(s); + + return r; +} + +static ssize_t +show_header_event_file(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) +{ + struct trace_seq *s; + int r; + + if (*ppos) + return 0; + + s = kmalloc(sizeof(*s), GFP_KERNEL); + if (!s) + return -ENOMEM; + + trace_seq_init(s); + + ring_buffer_print_entry_header(s); r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, trace_seq_used(s)); @@ -2165,10 +2189,18 @@ static const struct file_operations ftrace_tr_enable_fops = { .release = subsystem_release, }; -static const struct file_operations ftrace_show_header_fops = { - .open = tracing_open_generic, - .read = show_header, +static const struct file_operations ftrace_show_header_page_fops = { + .open = tracing_open_generic_tr, + .read = show_header_page_file, .llseek = default_llseek, + .release = tracing_release_generic_tr, +}; + +static const struct file_operations ftrace_show_header_event_fops = { + .open = tracing_open_generic_tr, + .read = show_header_event_file, + .llseek = default_llseek, + .release = tracing_release_generic_tr, }; static int @@ -3794,17 +3826,16 @@ static int events_callback(const char *name, umode_t *mode, void **data, return 1; } - if (strcmp(name, "header_page") == 0) - *data = ring_buffer_print_page_header; - - else if (strcmp(name, "header_event") == 0) - *data = ring_buffer_print_entry_header; + if (strcmp(name, "header_page") == 0) { + *mode = TRACE_MODE_READ; + *fops = &ftrace_show_header_page_fops; - else + } else if (strcmp(name, "header_event") == 0) { + *mode = TRACE_MODE_READ; + *fops = &ftrace_show_header_event_fops; + } else return 0; - *mode = TRACE_MODE_READ; - *fops = &ftrace_show_header_fops; return 1; } -- cgit v1.2.3