diff mbox

[v7,0/2] ring-buffer: Rename sub-buffer into buffer page

Message ID 20231218154618.954997-1-vdonnefort@google.com
State New
Headers

Commit Message

Vincent Donnefort Dec. 18, 2023, 3:46 p.m. UTC 
  Previously was introduced the ability to change the ring-buffer page
size. It also introduced the concept of sub-buffer that is, a contiguous
virtual memory space which can now be bigger than the system page size
(4K on most systems). But behind the scene this is really just a page
with an order > 0 and a struct buffer_page (often refered as "bpage")
already exists. We have then an unnecessary duplicate subbuffer ==
bpage.

Remove all references to sub-buffer and replace them with either bpage
or ring_buffer_page.

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>

---

I forgot this patch when sending the v7 :-(

Comments

Steven Rostedt Dec. 18, 2023, 4:28 p.m. UTC | #1 
On Mon, 18 Dec 2023 15:46:18 +0000
Vincent Donnefort <vdonnefort@google.com> wrote:

> Previously was introduced the ability to change the ring-buffer page
> size. It also introduced the concept of sub-buffer that is, a contiguous
> virtual memory space which can now be bigger than the system page size
> (4K on most systems). But behind the scene this is really just a page
> with an order > 0 and a struct buffer_page (often refered as "bpage")
> already exists. We have then an unnecessary duplicate subbuffer ==
> bpage.
> 
> Remove all references to sub-buffer and replace them with either bpage
> or ring_buffer_page.

No! I think you misunderstood me before.

I want it the other way around. In Linux, "page" usually means the
architecture page (4096 on x86). If we are going to remove the duplicate of
subbuffer == bpage, remove the "page" part, *not* the subbuffer part. The
"subbuf" part is part of the design, not an implementation detail. The page
part, was just an implementation detail that we do not want to expose!

When you say "page" you mean a single page. If you say buffer_page_size,
one will think this is an architecture page, not the subbuffer size.

The ring buffer is broken up into subbuffers, The page is just an
implementation detail. Let's not confuse that with the design.

Thanks,

-- Steve
Steven Rostedt Dec. 18, 2023, 4:43 p.m. UTC | #2 
On Mon, 18 Dec 2023 11:28:17 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> > Remove all references to sub-buffer and replace them with either bpage
> > or ring_buffer_page.  

The user interface should not be changed.

But what I would like to have changed (and this will come after all other
changes are complete), is to do the following renaming:

  original structure name		new name		variable reference
  -----------------------		--------		------------------
 struct buffer_data_page		struct buffer_data	bdata  (was bpage)
 struct buffer_page			struct buffer_subbuf	subbuf (was also bpage)

Also change:

struct buffer_page {
	[..]
	struct buffer_data_page *page;	/* Actual data page */
};

Into:

struct buffer_subbuf {
	[..]
	struct buffer_data *data;	/* Actual data */
};



Then we can do a global rename of functions like:

 free_buffer_page() -> free_buffer_subbuf()

And things like rb_init_page() into rb_init_subbuf()

__rb_allocate_pages() -> rb_allocate_subbufs()

etc.

This should be broken up into steps of changes:

1. Rename the struct buffer_data_page and bpage->bdata
2. Rename the struct buffer_page and bpage->subbuf
3. Rename static functions

And I just realized that the two functions exposed outside of the file are
not used anywhere else. We can remove one and make the other one static (as
it is used within the file).

ring_buffer_nr_pages() -> delete
ring_buffer_nr_dirty_pages -> convert to static rb_nr_dirty_pages()


Thanks,

-- Steve
diff mbox

Patch

diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst
index 8571d84d129b..4cd1d89b4ac6 100644
--- a/Documentation/trace/ftrace.rst
+++ b/Documentation/trace/ftrace.rst
@@ -203,26 +203,26 @@  of ftrace. Here is a list of some of the key files:
 
 	This displays the total combined size of all the trace buffers.
 
-  buffer_subbuf_size_kb:
-
-	This sets or displays the sub buffer size. The ring buffer is broken up
-	into several same size "sub buffers". An event can not be bigger than
-	the size of the sub buffer. Normally, the sub buffer is the size of the
-	architecture's page (4K on x86). The sub buffer also contains meta data
-	at the start which also limits the size of an event.  That means when
-	the sub buffer is a page size, no event can be larger than the page
-	size minus the sub buffer meta data.
-
-	Note, the buffer_subbuf_size_kb is a way for the user to specify the
-	minimum size of the subbuffer. The kernel may make it bigger due to the
-	implementation details, or simply fail the operation if the kernel can
-	not handle the request.
-
-	Changing the sub buffer size allows for events to be larger than the
-	page size.
-
-	Note: When changing the sub-buffer size, tracing is stopped and any
-	data in the ring buffer and the snapshot buffer will be discarded.
+  buffer_page_size_kb:
+
+        This sets or displays the ring-buffer page size. The ring buffer is
+        broken up into several same size "buffer pages". An event can not be
+        bigger than the size of the buffer page. Normally, the buffer page is
+        the size of the architecture's page (4K on x86). The buffer page also
+        contains meta data at the start which also limits the size of an event.
+        That means when the buffer page is a system page size, no event can be
+        larger than the system page size minus the buffer page meta data.
+
+        Note, the buffer_page_size_kb is a way for the user to specify the
+        minimum size for each buffer page. The kernel may make it bigger due to
+        the implementation details, or simply fail the operation if the kernel
+        can not handle the request.
+
+        Changing the ring-buffer page size allows for events to be larger than
+        the system page size.
+
+        Note: When changing the buffer page size, tracing is stopped and any
+        data in the ring buffer and the snapshot buffer will be discarded.
 
   free_buffer:
 
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index fa802db216f9..929ed54dd651 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -207,9 +207,9 @@  struct trace_seq;
 int ring_buffer_print_entry_header(struct trace_seq *s);
 int ring_buffer_print_page_header(struct trace_buffer *buffer, struct trace_seq *s);
 
-int ring_buffer_subbuf_order_get(struct trace_buffer *buffer);
-int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order);
-int ring_buffer_subbuf_size_get(struct trace_buffer *buffer);
+int ring_buffer_page_order_get(struct trace_buffer *buffer);
+int ring_buffer_page_order_set(struct trace_buffer *buffer, int order);
+int ring_buffer_page_size_get(struct trace_buffer *buffer);
 
 enum ring_buffer_flags {
 	RB_FL_OVERWRITE		= 1 << 0,
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 9b95297339b6..f95ad0f5be1b 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -511,8 +511,8 @@  struct trace_buffer {
 	struct rb_irq_work		irq_work;
 	bool				time_stamp_abs;
 
-	unsigned int			subbuf_size;
-	unsigned int			subbuf_order;
+	unsigned int			bpage_size;
+	unsigned int			bpage_order;
 	unsigned int			max_data_size;
 };
 
@@ -555,7 +555,7 @@  int ring_buffer_print_page_header(struct trace_buffer *buffer, struct trace_seq
 	trace_seq_printf(s, "\tfield: char data;\t"
 			 "offset:%u;\tsize:%u;\tsigned:%u;\n",
 			 (unsigned int)offsetof(typeof(field), data),
-			 (unsigned int)buffer->subbuf_size,
+			 (unsigned int)buffer->bpage_size,
 			 (unsigned int)is_signed_type(char));
 
 	return !trace_seq_has_overflowed(s);
@@ -1488,11 +1488,11 @@  static int __rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
 		list_add(&bpage->list, pages);
 
 		page = alloc_pages_node(cpu_to_node(cpu_buffer->cpu), mflags,
-					cpu_buffer->buffer->subbuf_order);
+					cpu_buffer->buffer->bpage_order);
 		if (!page)
 			goto free_pages;
 		bpage->page = page_address(page);
-		bpage->order = cpu_buffer->buffer->subbuf_order;
+		bpage->order = cpu_buffer->buffer->bpage_order;
 		rb_init_page(bpage->page);
 
 		if (user_thread && fatal_signal_pending(current))
@@ -1572,7 +1572,7 @@  rb_allocate_cpu_buffer(struct trace_buffer *buffer, long nr_pages, int cpu)
 
 	cpu_buffer->reader_page = bpage;
 
-	page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL, cpu_buffer->buffer->subbuf_order);
+	page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL, cpu_buffer->buffer->bpage_order);
 	if (!page)
 		goto fail_free_reader;
 	bpage->page = page_address(page);
@@ -1656,13 +1656,13 @@  struct trace_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
 		goto fail_free_buffer;
 
 	/* Default buffer page size - one system page */
-	buffer->subbuf_order = 0;
-	buffer->subbuf_size = PAGE_SIZE - BUF_PAGE_HDR_SIZE;
+	buffer->bpage_order = 0;
+	buffer->bpage_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);
+	buffer->max_data_size = buffer->bpage_size - (sizeof(u32) * 2);
 
-	nr_pages = DIV_ROUND_UP(size, buffer->subbuf_size);
+	nr_pages = DIV_ROUND_UP(size, buffer->bpage_size);
 	buffer->flags = flags;
 	buffer->clock = trace_clock_local;
 	buffer->reader_lock_key = key;
@@ -1981,7 +1981,7 @@  static void update_pages_handler(struct work_struct *work)
  * @size: the new size.
  * @cpu_id: the cpu buffer to resize
  *
- * Minimum size is 2 * buffer->subbuf_size.
+ * Minimum size is 2 * buffer->bpage_size.
  *
  * Returns 0 on success and < 0 on failure.
  */
@@ -2003,7 +2003,7 @@  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, buffer->subbuf_size);
+	nr_pages = DIV_ROUND_UP(size, buffer->bpage_size);
 
 	/* we need a minimum of two pages */
 	if (nr_pages < 2)
@@ -2483,7 +2483,7 @@  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);
+	unsigned long bsize = READ_ONCE(cpu_buffer->buffer->bpage_size);
 	struct buffer_page *tail_page = info->tail_page;
 	struct ring_buffer_event *event;
 	unsigned long length = info->length;
@@ -3426,7 +3426,7 @@  __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 > cpu_buffer->buffer->subbuf_size)) {
+	if (unlikely(write > cpu_buffer->buffer->bpage_size)) {
 		check_buffer(cpu_buffer, info, CHECK_FULL_PAGE);
 		return rb_move_tail(cpu_buffer, tail, info);
 	}
@@ -4355,7 +4355,7 @@  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 bsize = READ_ONCE(cpu_buffer->buffer->bpage_size);
 	unsigned long overwrite;
 	unsigned long flags;
 	int nr_loops = 0;
@@ -4935,7 +4935,7 @@  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_size = buffer->subbuf_size;
+	iter->event_size = buffer->bpage_size;
 	iter->event = kmalloc(iter->event_size, flags);
 	if (!iter->event) {
 		kfree(iter);
@@ -5054,14 +5054,14 @@  unsigned long ring_buffer_size(struct trace_buffer *buffer, int cpu)
 {
 	/*
 	 * Earlier, this method returned
-	 *	buffer->subbuf_size * buffer->nr_pages
+	 *	buffer->bpage_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 buffer->subbuf_size * buffer->buffers[cpu]->nr_pages;
+	return buffer->bpage_size * buffer->buffers[cpu]->nr_pages;
 }
 EXPORT_SYMBOL_GPL(ring_buffer_size);
 
@@ -5350,7 +5350,7 @@  int ring_buffer_swap_cpu(struct trace_buffer *buffer_a,
 	if (cpu_buffer_a->nr_pages != cpu_buffer_b->nr_pages)
 		goto out;
 
-	if (buffer_a->subbuf_order != buffer_b->subbuf_order)
+	if (buffer_a->bpage_order != buffer_b->bpage_order)
 		goto out;
 
 	ret = -EAGAIN;
@@ -5439,7 +5439,7 @@  ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu)
 	if (!bpage)
 		return ERR_PTR(-ENOMEM);
 
-	bpage->order = buffer->subbuf_order;
+	bpage->order = buffer->bpage_order;
 	cpu_buffer = buffer->buffers[cpu];
 	local_irq_save(flags);
 	arch_spin_lock(&cpu_buffer->lock);
@@ -5456,7 +5456,7 @@  ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu)
 		goto out;
 
 	page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL | __GFP_NORETRY,
-				cpu_buffer->buffer->subbuf_order);
+				cpu_buffer->buffer->bpage_order);
 	if (!page) {
 		kfree(bpage);
 		return ERR_PTR(-ENOMEM);
@@ -5494,10 +5494,10 @@  void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu,
 
 	/*
 	 * If the page is still in use someplace else, or order of the page
-	 * is different from the subbuffer order of the buffer -
+	 * is different from the bpage order of the buffer -
 	 * we can't reuse it
 	 */
-	if (page_ref_count(page) > 1 || data_page->order != buffer->subbuf_order)
+	if (page_ref_count(page) > 1 || data_page->order != buffer->bpage_order)
 		goto out;
 
 	local_irq_save(flags);
@@ -5580,7 +5580,7 @@  int ring_buffer_read_page(struct trace_buffer *buffer,
 
 	if (!data_page || !data_page->data)
 		goto out;
-	if (data_page->order != buffer->subbuf_order)
+	if (data_page->order != buffer->bpage_order)
 		goto out;
 
 	bpage = data_page->data;
@@ -5703,7 +5703,7 @@  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 (buffer->subbuf_size - commit >= sizeof(missed_events)) {
+		if (buffer->bpage_size - commit >= sizeof(missed_events)) {
 			memcpy(&bpage->data[commit], &missed_events,
 			       sizeof(missed_events));
 			local_add(RB_MISSED_STORED, &bpage->commit);
@@ -5715,8 +5715,8 @@  int ring_buffer_read_page(struct trace_buffer *buffer,
 	/*
 	 * This page may be off to user land. Zero it out here.
 	 */
-	if (commit < buffer->subbuf_size)
-		memset(&bpage->data[commit], 0, buffer->subbuf_size - commit);
+	if (commit < buffer->bpage_size)
+		memset(&bpage->data[commit], 0, buffer->bpage_size - commit);
 
  out_unlock:
 	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
@@ -5739,19 +5739,19 @@  void *ring_buffer_read_page_data(struct buffer_data_read_page *page)
 EXPORT_SYMBOL_GPL(ring_buffer_read_page_data);
 
 /**
- * ring_buffer_subbuf_size_get - get size of the sub buffer.
+ * ring_buffer_page_size_get - get size of the sub buffer.
  * @buffer: the buffer to get the sub buffer size from
  *
  * Returns size of the sub buffer, in bytes.
  */
-int ring_buffer_subbuf_size_get(struct trace_buffer *buffer)
+int ring_buffer_page_size_get(struct trace_buffer *buffer)
 {
-	return buffer->subbuf_size + BUF_PAGE_HDR_SIZE;
+	return buffer->bpage_size + BUF_PAGE_HDR_SIZE;
 }
-EXPORT_SYMBOL_GPL(ring_buffer_subbuf_size_get);
+EXPORT_SYMBOL_GPL(ring_buffer_page_size_get);
 
 /**
- * ring_buffer_subbuf_order_get - get order of system sub pages in one buffer page.
+ * ring_buffer_page_order_get - get order of system sub pages in one buffer page.
  * @buffer: The ring_buffer to get the system sub page order from
  *
  * By default, one ring buffer sub page equals to one system page. This parameter
@@ -5762,17 +5762,17 @@  EXPORT_SYMBOL_GPL(ring_buffer_subbuf_size_get);
  * 0 means the sub buffer size is 1 system page and so forth.
  * In case of an error < 0 is returned.
  */
-int ring_buffer_subbuf_order_get(struct trace_buffer *buffer)
+int ring_buffer_page_order_get(struct trace_buffer *buffer)
 {
 	if (!buffer)
 		return -EINVAL;
 
-	return buffer->subbuf_order;
+	return buffer->bpage_order;
 }
-EXPORT_SYMBOL_GPL(ring_buffer_subbuf_order_get);
+EXPORT_SYMBOL_GPL(ring_buffer_page_order_get);
 
 /**
- * ring_buffer_subbuf_order_set - set the size of ring buffer sub page.
+ * ring_buffer_page_order_set - set the size of ring buffer sub page.
  * @buffer: The ring_buffer to set the new page size.
  * @order: Order of the system pages in one sub buffer page
  *
@@ -5787,7 +5787,7 @@  EXPORT_SYMBOL_GPL(ring_buffer_subbuf_order_get);
  *
  * Returns 0 on success or < 0 in case of an error.
  */
-int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order)
+int ring_buffer_page_order_set(struct trace_buffer *buffer, int order)
 {
 	struct ring_buffer_per_cpu *cpu_buffer;
 	struct buffer_page *bpage, *tmp;
@@ -5800,15 +5800,15 @@  int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order)
 	if (!buffer || order < 0)
 		return -EINVAL;
 
-	if (buffer->subbuf_order == order)
+	if (buffer->bpage_order == order)
 		return 0;
 
 	psize = (1 << order) * PAGE_SIZE;
 	if (psize <= BUF_PAGE_HDR_SIZE)
 		return -EINVAL;
 
-	old_order = buffer->subbuf_order;
-	old_size = buffer->subbuf_size;
+	old_order = buffer->bpage_order;
+	old_size = buffer->bpage_size;
 
 	/* prevent another thread from changing buffer sizes */
 	mutex_lock(&buffer->mutex);
@@ -5817,8 +5817,8 @@  int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order)
 	/* Make sure all commits have finished */
 	synchronize_rcu();
 
-	buffer->subbuf_order = order;
-	buffer->subbuf_size = psize - BUF_PAGE_HDR_SIZE;
+	buffer->bpage_order = order;
+	buffer->bpage_size = psize - BUF_PAGE_HDR_SIZE;
 
 	/* Make sure all new buffers are allocated, before deleting the old ones */
 	for_each_buffer_cpu(buffer, cpu) {
@@ -5830,7 +5830,7 @@  int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order)
 
 		/* Update the number of pages to match the new size */
 		nr_pages = old_size * buffer->buffers[cpu]->nr_pages;
-		nr_pages = DIV_ROUND_UP(nr_pages, buffer->subbuf_size);
+		nr_pages = DIV_ROUND_UP(nr_pages, buffer->bpage_size);
 
 		/* we need a minimum of two pages */
 		if (nr_pages < 2)
@@ -5907,8 +5907,8 @@  int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order)
 	return 0;
 
 error:
-	buffer->subbuf_order = old_order;
-	buffer->subbuf_size = old_size;
+	buffer->bpage_order = old_order;
+	buffer->bpage_size = old_size;
 
 	atomic_dec(&buffer->record_disabled);
 	mutex_unlock(&buffer->mutex);
@@ -5927,7 +5927,7 @@  int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order)
 
 	return err;
 }
-EXPORT_SYMBOL_GPL(ring_buffer_subbuf_order_set);
+EXPORT_SYMBOL_GPL(ring_buffer_page_order_set);
 
 /*
  * We only allocate new buffers, never free them if the CPU goes down.
diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c
index 008187ebd7fe..b58ced8f4626 100644
--- a/kernel/trace/ring_buffer_benchmark.c
+++ b/kernel/trace/ring_buffer_benchmark.c
@@ -118,7 +118,7 @@  static enum event_status read_page(int cpu)
 	if (IS_ERR(bpage))
 		return EVENT_DROPPED;
 
-	page_size = ring_buffer_subbuf_size_get(buffer);
+	page_size = ring_buffer_page_size_get(buffer);
 	ret = ring_buffer_read_page(buffer, bpage, page_size, cpu, 1);
 	if (ret >= 0) {
 		rpage = ring_buffer_read_page_data(bpage);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index b35c85edbb49..c17dd849e6f1 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1269,8 +1269,8 @@  int tracing_alloc_snapshot_instance(struct trace_array *tr)
 	if (!tr->allocated_snapshot) {
 
 		/* Make the snapshot buffer have the same order as main buffer */
-		order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
-		ret = ring_buffer_subbuf_order_set(tr->max_buffer.buffer, order);
+		order = ring_buffer_page_order_get(tr->array_buffer.buffer);
+		ret = ring_buffer_page_order_set(tr->max_buffer.buffer, order);
 		if (ret < 0)
 			return ret;
 
@@ -1293,7 +1293,7 @@  static void free_snapshot(struct trace_array *tr)
 	 * The max_tr ring buffer has some state (e.g. ring->clock) and
 	 * we want preserve it.
 	 */
-	ring_buffer_subbuf_order_set(tr->max_buffer.buffer, 0);
+	ring_buffer_page_order_set(tr->max_buffer.buffer, 0);
 	ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
 	set_buffer_entries(&tr->max_buffer, 1);
 	tracing_reset_online_cpus(&tr->max_buffer);
@@ -8315,7 +8315,7 @@  tracing_buffers_read(struct file *filp, char __user *ubuf,
 		return -EBUSY;
 #endif
 
-	page_size = ring_buffer_subbuf_size_get(iter->array_buffer->buffer);
+	page_size = ring_buffer_page_size_get(iter->array_buffer->buffer);
 
 	/* Make sure the spare matches the current sub buffer size */
 	if (info->spare) {
@@ -8492,7 +8492,7 @@  tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 		return -EBUSY;
 #endif
 
-	page_size = ring_buffer_subbuf_size_get(iter->array_buffer->buffer);
+	page_size = ring_buffer_page_size_get(iter->array_buffer->buffer);
 	if (*ppos & (page_size - 1))
 		return -EINVAL;
 
@@ -9391,7 +9391,7 @@  static const struct file_operations buffer_percent_fops = {
 };
 
 static ssize_t
-buffer_subbuf_size_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
+buffer_page_size_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 {
 	struct trace_array *tr = filp->private_data;
 	size_t size;
@@ -9399,7 +9399,7 @@  buffer_subbuf_size_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t
 	int order;
 	int r;
 
-	order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
+	order = ring_buffer_page_order_get(tr->array_buffer.buffer);
 	size = (PAGE_SIZE << order) / 1024;
 
 	r = sprintf(buf, "%zd\n", size);
@@ -9408,8 +9408,8 @@  buffer_subbuf_size_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t
 }
 
 static ssize_t
-buffer_subbuf_size_write(struct file *filp, const char __user *ubuf,
-			 size_t cnt, loff_t *ppos)
+buffer_page_size_write(struct file *filp, const char __user *ubuf,
+		       size_t cnt, loff_t *ppos)
 {
 	struct trace_array *tr = filp->private_data;
 	unsigned long val;
@@ -9434,11 +9434,11 @@  buffer_subbuf_size_write(struct file *filp, const char __user *ubuf,
 	/* Do not allow tracing while changing the order of the ring buffer */
 	tracing_stop_tr(tr);
 
-	old_order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
+	old_order = ring_buffer_page_order_get(tr->array_buffer.buffer);
 	if (old_order == order)
 		goto out;
 
-	ret = ring_buffer_subbuf_order_set(tr->array_buffer.buffer, order);
+	ret = ring_buffer_page_order_set(tr->array_buffer.buffer, order);
 	if (ret)
 		goto out;
 
@@ -9447,10 +9447,10 @@  buffer_subbuf_size_write(struct file *filp, const char __user *ubuf,
 	if (!tr->allocated_snapshot)
 		goto out_max;
 
-	ret = ring_buffer_subbuf_order_set(tr->max_buffer.buffer, order);
+	ret = ring_buffer_page_order_set(tr->max_buffer.buffer, order);
 	if (ret) {
 		/* Put back the old order */
-		cnt = ring_buffer_subbuf_order_set(tr->array_buffer.buffer, old_order);
+		cnt = ring_buffer_page_order_set(tr->array_buffer.buffer, old_order);
 		if (WARN_ON_ONCE(cnt)) {
 			/*
 			 * AARGH! We are left with different orders!
@@ -9479,10 +9479,10 @@  buffer_subbuf_size_write(struct file *filp, const char __user *ubuf,
 	return cnt;
 }
 
-static const struct file_operations buffer_subbuf_size_fops = {
+static const struct file_operations buffer_page_size_fops = {
 	.open		= tracing_open_generic_tr,
-	.read		= buffer_subbuf_size_read,
-	.write		= buffer_subbuf_size_write,
+	.read		= buffer_page_size_read,
+	.write		= buffer_page_size_write,
 	.release	= tracing_release_generic_tr,
 	.llseek		= default_llseek,
 };
@@ -9953,8 +9953,8 @@  init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
 	trace_create_file("buffer_percent", TRACE_MODE_WRITE, d_tracer,
 			tr, &buffer_percent_fops);
 
-	trace_create_file("buffer_subbuf_size_kb", TRACE_MODE_WRITE, d_tracer,
-			  tr, &buffer_subbuf_size_fops);
+	trace_create_file("buffer_page_size_kb", TRACE_MODE_WRITE, d_tracer,
+			  tr, &buffer_page_size_fops);
 
 	create_trace_options_dir(tr);