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* [PATCH v2] perf/x86: Rename local bts_buffer variables
@ 2025-04-07  8:52 Thorsten Blum
  2025-04-09 11:43 ` [tip: perf/core] perf/x86/intel/bts: Rename local bts_buffer variables for clarity tip-bot2 for Thorsten Blum
  0 siblings, 1 reply; 2+ messages in thread
From: Thorsten Blum @ 2025-04-07  8:52 UTC (permalink / raw)
  To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
	Namhyung Kim, Mark Rutland, Alexander Shishkin, Jiri Olsa,
	Ian Rogers, Adrian Hunter, Liang, Kan, Thomas Gleixner,
	Borislav Petkov, Dave Hansen, x86, H. Peter Anvin
  Cc: Thorsten Blum, Ingo Molnar, linux-perf-users, linux-kernel

Rename struct bts_buffer objects from 'buf' to 'bb' to improve the
readability when accessing the structure's 'buf' member. For example,
'buf->buf[]' becomes 'bb->buf[]'.

Indent line 327 using tabs to silence a checkpatch warning.

No functional changes intended.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
Changes in v2:
- struct_size() change should be a separate patch as suggested by Peter
- Link to v1: https://lore.kernel.org/lkml/20250331122938.1837255-2-thorsten.blum@linux.dev/
---
 arch/x86/events/intel/bts.c | 144 ++++++++++++++++++------------------
 1 file changed, 72 insertions(+), 72 deletions(-)

diff --git a/arch/x86/events/intel/bts.c b/arch/x86/events/intel/bts.c
index a95e6c91c4d7..16bc89c8023b 100644
--- a/arch/x86/events/intel/bts.c
+++ b/arch/x86/events/intel/bts.c
@@ -80,54 +80,54 @@ static void *
 bts_buffer_setup_aux(struct perf_event *event, void **pages,
 		     int nr_pages, bool overwrite)
 {
-	struct bts_buffer *buf;
+	struct bts_buffer *bb;
 	struct page *page;
 	int cpu = event->cpu;
 	int node = (cpu == -1) ? cpu : cpu_to_node(cpu);
 	unsigned long offset;
 	size_t size = nr_pages << PAGE_SHIFT;
-	int pg, nbuf, pad;
+	int pg, nr_buf, pad;
 
 	/* count all the high order buffers */
-	for (pg = 0, nbuf = 0; pg < nr_pages;) {
+	for (pg = 0, nr_buf = 0; pg < nr_pages;) {
 		page = virt_to_page(pages[pg]);
 		pg += buf_nr_pages(page);
-		nbuf++;
+		nr_buf++;
 	}
 
 	/*
 	 * to avoid interrupts in overwrite mode, only allow one physical
 	 */
-	if (overwrite && nbuf > 1)
+	if (overwrite && nr_buf > 1)
 		return NULL;
 
-	buf = kzalloc_node(offsetof(struct bts_buffer, buf[nbuf]), GFP_KERNEL, node);
-	if (!buf)
+	bb = kzalloc_node(offsetof(struct bts_buffer, buf[nr_buf]), GFP_KERNEL, node);
+	if (!bb)
 		return NULL;
 
-	buf->nr_pages = nr_pages;
-	buf->nr_bufs = nbuf;
-	buf->snapshot = overwrite;
-	buf->data_pages = pages;
-	buf->real_size = size - size % BTS_RECORD_SIZE;
+	bb->nr_pages = nr_pages;
+	bb->nr_bufs = nr_buf;
+	bb->snapshot = overwrite;
+	bb->data_pages = pages;
+	bb->real_size = size - size % BTS_RECORD_SIZE;
 
-	for (pg = 0, nbuf = 0, offset = 0, pad = 0; nbuf < buf->nr_bufs; nbuf++) {
+	for (pg = 0, nr_buf = 0, offset = 0, pad = 0; nr_buf < bb->nr_bufs; nr_buf++) {
 		unsigned int __nr_pages;
 
 		page = virt_to_page(pages[pg]);
 		__nr_pages = buf_nr_pages(page);
-		buf->buf[nbuf].page = page;
-		buf->buf[nbuf].offset = offset;
-		buf->buf[nbuf].displacement = (pad ? BTS_RECORD_SIZE - pad : 0);
-		buf->buf[nbuf].size = buf_size(page) - buf->buf[nbuf].displacement;
-		pad = buf->buf[nbuf].size % BTS_RECORD_SIZE;
-		buf->buf[nbuf].size -= pad;
+		bb->buf[nr_buf].page = page;
+		bb->buf[nr_buf].offset = offset;
+		bb->buf[nr_buf].displacement = (pad ? BTS_RECORD_SIZE - pad : 0);
+		bb->buf[nr_buf].size = buf_size(page) - bb->buf[nr_buf].displacement;
+		pad = bb->buf[nr_buf].size % BTS_RECORD_SIZE;
+		bb->buf[nr_buf].size -= pad;
 
 		pg += __nr_pages;
 		offset += __nr_pages << PAGE_SHIFT;
 	}
 
-	return buf;
+	return bb;
 }
 
 static void bts_buffer_free_aux(void *data)
@@ -135,25 +135,25 @@ static void bts_buffer_free_aux(void *data)
 	kfree(data);
 }
 
-static unsigned long bts_buffer_offset(struct bts_buffer *buf, unsigned int idx)
+static unsigned long bts_buffer_offset(struct bts_buffer *bb, unsigned int idx)
 {
-	return buf->buf[idx].offset + buf->buf[idx].displacement;
+	return bb->buf[idx].offset + bb->buf[idx].displacement;
 }
 
 static void
-bts_config_buffer(struct bts_buffer *buf)
+bts_config_buffer(struct bts_buffer *bb)
 {
 	int cpu = raw_smp_processor_id();
 	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
-	struct bts_phys *phys = &buf->buf[buf->cur_buf];
+	struct bts_phys *phys = &bb->buf[bb->cur_buf];
 	unsigned long index, thresh = 0, end = phys->size;
 	struct page *page = phys->page;
 
-	index = local_read(&buf->head);
+	index = local_read(&bb->head);
 
-	if (!buf->snapshot) {
-		if (buf->end < phys->offset + buf_size(page))
-			end = buf->end - phys->offset - phys->displacement;
+	if (!bb->snapshot) {
+		if (bb->end < phys->offset + buf_size(page))
+			end = bb->end - phys->offset - phys->displacement;
 
 		index -= phys->offset + phys->displacement;
 
@@ -168,7 +168,7 @@ bts_config_buffer(struct bts_buffer *buf)
 	ds->bts_buffer_base = (u64)(long)page_address(page) + phys->displacement;
 	ds->bts_index = ds->bts_buffer_base + index;
 	ds->bts_absolute_maximum = ds->bts_buffer_base + end;
-	ds->bts_interrupt_threshold = !buf->snapshot
+	ds->bts_interrupt_threshold = !bb->snapshot
 		? ds->bts_buffer_base + thresh
 		: ds->bts_absolute_maximum + BTS_RECORD_SIZE;
 }
@@ -184,16 +184,16 @@ static void bts_update(struct bts_ctx *bts)
 {
 	int cpu = raw_smp_processor_id();
 	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
-	struct bts_buffer *buf = perf_get_aux(&bts->handle);
+	struct bts_buffer *bb = perf_get_aux(&bts->handle);
 	unsigned long index = ds->bts_index - ds->bts_buffer_base, old, head;
 
-	if (!buf)
+	if (!bb)
 		return;
 
-	head = index + bts_buffer_offset(buf, buf->cur_buf);
-	old = local_xchg(&buf->head, head);
+	head = index + bts_buffer_offset(bb, bb->cur_buf);
+	old = local_xchg(&bb->head, head);
 
-	if (!buf->snapshot) {
+	if (!bb->snapshot) {
 		if (old == head)
 			return;
 
@@ -205,9 +205,9 @@ static void bts_update(struct bts_ctx *bts)
 		 * old and head are always in the same physical buffer, so we
 		 * can subtract them to get the data size.
 		 */
-		local_add(head - old, &buf->data_size);
+		local_add(head - old, &bb->data_size);
 	} else {
-		local_set(&buf->data_size, head);
+		local_set(&bb->data_size, head);
 	}
 
 	/*
@@ -218,7 +218,7 @@ static void bts_update(struct bts_ctx *bts)
 }
 
 static int
-bts_buffer_reset(struct bts_buffer *buf, struct perf_output_handle *handle);
+bts_buffer_reset(struct bts_buffer *bb, struct perf_output_handle *handle);
 
 /*
  * Ordering PMU callbacks wrt themselves and the PMI is done by means
@@ -232,17 +232,17 @@ bts_buffer_reset(struct bts_buffer *buf, struct perf_output_handle *handle);
 static void __bts_event_start(struct perf_event *event)
 {
 	struct bts_ctx *bts = this_cpu_ptr(bts_ctx);
-	struct bts_buffer *buf = perf_get_aux(&bts->handle);
+	struct bts_buffer *bb = perf_get_aux(&bts->handle);
 	u64 config = 0;
 
-	if (!buf->snapshot)
+	if (!bb->snapshot)
 		config |= ARCH_PERFMON_EVENTSEL_INT;
 	if (!event->attr.exclude_kernel)
 		config |= ARCH_PERFMON_EVENTSEL_OS;
 	if (!event->attr.exclude_user)
 		config |= ARCH_PERFMON_EVENTSEL_USR;
 
-	bts_config_buffer(buf);
+	bts_config_buffer(bb);
 
 	/*
 	 * local barrier to make sure that ds configuration made it
@@ -261,13 +261,13 @@ static void bts_event_start(struct perf_event *event, int flags)
 {
 	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
 	struct bts_ctx *bts = this_cpu_ptr(bts_ctx);
-	struct bts_buffer *buf;
+	struct bts_buffer *bb;
 
-	buf = perf_aux_output_begin(&bts->handle, event);
-	if (!buf)
+	bb = perf_aux_output_begin(&bts->handle, event);
+	if (!bb)
 		goto fail_stop;
 
-	if (bts_buffer_reset(buf, &bts->handle))
+	if (bts_buffer_reset(bb, &bts->handle))
 		goto fail_end_stop;
 
 	bts->ds_back.bts_buffer_base = cpuc->ds->bts_buffer_base;
@@ -306,27 +306,27 @@ static void bts_event_stop(struct perf_event *event, int flags)
 {
 	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
 	struct bts_ctx *bts = this_cpu_ptr(bts_ctx);
-	struct bts_buffer *buf = NULL;
+	struct bts_buffer *bb = NULL;
 	int state = READ_ONCE(bts->state);
 
 	if (state == BTS_STATE_ACTIVE)
 		__bts_event_stop(event, BTS_STATE_STOPPED);
 
 	if (state != BTS_STATE_STOPPED)
-		buf = perf_get_aux(&bts->handle);
+		bb = perf_get_aux(&bts->handle);
 
 	event->hw.state |= PERF_HES_STOPPED;
 
 	if (flags & PERF_EF_UPDATE) {
 		bts_update(bts);
 
-		if (buf) {
-			if (buf->snapshot)
+		if (bb) {
+			if (bb->snapshot)
 				bts->handle.head =
-					local_xchg(&buf->data_size,
-						   buf->nr_pages << PAGE_SHIFT);
+					local_xchg(&bb->data_size,
+						   bb->nr_pages << PAGE_SHIFT);
 			perf_aux_output_end(&bts->handle,
-			                    local_xchg(&buf->data_size, 0));
+					    local_xchg(&bb->data_size, 0));
 		}
 
 		cpuc->ds->bts_index = bts->ds_back.bts_buffer_base;
@@ -382,19 +382,19 @@ void intel_bts_disable_local(void)
 }
 
 static int
-bts_buffer_reset(struct bts_buffer *buf, struct perf_output_handle *handle)
+bts_buffer_reset(struct bts_buffer *bb, struct perf_output_handle *handle)
 {
 	unsigned long head, space, next_space, pad, gap, skip, wakeup;
 	unsigned int next_buf;
 	struct bts_phys *phys, *next_phys;
 	int ret;
 
-	if (buf->snapshot)
+	if (bb->snapshot)
 		return 0;
 
-	head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1);
+	head = handle->head & ((bb->nr_pages << PAGE_SHIFT) - 1);
 
-	phys = &buf->buf[buf->cur_buf];
+	phys = &bb->buf[bb->cur_buf];
 	space = phys->offset + phys->displacement + phys->size - head;
 	pad = space;
 	if (space > handle->size) {
@@ -403,10 +403,10 @@ bts_buffer_reset(struct bts_buffer *buf, struct perf_output_handle *handle)
 	}
 	if (space <= BTS_SAFETY_MARGIN) {
 		/* See if next phys buffer has more space */
-		next_buf = buf->cur_buf + 1;
-		if (next_buf >= buf->nr_bufs)
+		next_buf = bb->cur_buf + 1;
+		if (next_buf >= bb->nr_bufs)
 			next_buf = 0;
-		next_phys = &buf->buf[next_buf];
+		next_phys = &bb->buf[next_buf];
 		gap = buf_size(phys->page) - phys->displacement - phys->size +
 		      next_phys->displacement;
 		skip = pad + gap;
@@ -431,8 +431,8 @@ bts_buffer_reset(struct bts_buffer *buf, struct perf_output_handle *handle)
 				 * anymore, so we must not be racing with
 				 * bts_update().
 				 */
-				buf->cur_buf = next_buf;
-				local_set(&buf->head, head);
+				bb->cur_buf = next_buf;
+				local_set(&bb->head, head);
 			}
 		}
 	}
@@ -445,7 +445,7 @@ bts_buffer_reset(struct bts_buffer *buf, struct perf_output_handle *handle)
 		space -= space % BTS_RECORD_SIZE;
 	}
 
-	buf->end = head + space;
+	bb->end = head + space;
 
 	/*
 	 * If we have no space, the lost notification would have been sent when
@@ -462,7 +462,7 @@ int intel_bts_interrupt(void)
 	struct debug_store *ds = this_cpu_ptr(&cpu_hw_events)->ds;
 	struct bts_ctx *bts;
 	struct perf_event *event;
-	struct bts_buffer *buf;
+	struct bts_buffer *bb;
 	s64 old_head;
 	int err = -ENOSPC, handled = 0;
 
@@ -485,8 +485,8 @@ int intel_bts_interrupt(void)
 	if (READ_ONCE(bts->state) == BTS_STATE_STOPPED)
 		return handled;
 
-	buf = perf_get_aux(&bts->handle);
-	if (!buf)
+	bb = perf_get_aux(&bts->handle);
+	if (!bb)
 		return handled;
 
 	/*
@@ -494,26 +494,26 @@ int intel_bts_interrupt(void)
 	 * there's no other way of telling, because the pointer will
 	 * keep moving
 	 */
-	if (buf->snapshot)
+	if (bb->snapshot)
 		return 0;
 
-	old_head = local_read(&buf->head);
+	old_head = local_read(&bb->head);
 	bts_update(bts);
 
 	/* no new data */
-	if (old_head == local_read(&buf->head))
+	if (old_head == local_read(&bb->head))
 		return handled;
 
-	perf_aux_output_end(&bts->handle, local_xchg(&buf->data_size, 0));
+	perf_aux_output_end(&bts->handle, local_xchg(&bb->data_size, 0));
 
-	buf = perf_aux_output_begin(&bts->handle, event);
-	if (buf)
-		err = bts_buffer_reset(buf, &bts->handle);
+	bb = perf_aux_output_begin(&bts->handle, event);
+	if (bb)
+		err = bts_buffer_reset(bb, &bts->handle);
 
 	if (err) {
 		WRITE_ONCE(bts->state, BTS_STATE_STOPPED);
 
-		if (buf) {
+		if (bb) {
 			/*
 			 * BTS_STATE_STOPPED should be visible before
 			 * cleared handle::event
-- 
2.49.0


^ permalink raw reply	[flat|nested] 2+ messages in thread
end of thread, other threads:[~2025-04-09 11:43 UTC | newest]

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2025-04-07  8:52 [PATCH v2] perf/x86: Rename local bts_buffer variables Thorsten Blum
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