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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1743424281; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=7XEWEmd5LWdFQWEvEb923ykZHXXlz1bJMpcel5KSrlk=; b=Oa0MvpIpXxMjZP67+MGyMm07znRrgBk/7woerEUR91JCGfKX0ao4riXEcBgUZKdL4eJmlK HLRw0sZrKd4OLPCwGa5kEdoVSsLOWBZyX9gFj4LpumWBEOOCEEHaW662OW8IBnZguoYSpj xXGFfPlRfH9Vpg5iTewB44kqgOqpEFE= From: Thorsten Blum 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@kernel.org, "H. Peter Anvin" Cc: Thorsten Blum , Ingo Molnar , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] perf/x86: Rename bts_buffer variables and use struct_size() Date: Mon, 31 Mar 2025 14:29:38 +0200 Message-ID: <20250331122938.1837255-2-thorsten.blum@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT 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[]'. Use struct_size() to calculate the number of bytes to allocate for a new bts_buffer. Compared to offsetof(), struct_size() provides additional compile-time checks (e.g., __must_be_array()). Indent line 327 using tabs to silence a checkpatch warning. No functional changes intended. Suggested-by: Ingo Molnar Signed-off-by: Thorsten Blum --- arch/x86/events/intel/bts.c | 146 ++++++++++++++++++------------------ 1 file changed, 72 insertions(+), 74 deletions(-) diff --git a/arch/x86/events/intel/bts.c b/arch/x86/events/intel/bts.c index a95e6c91c4d7..bbc7d914050c 100644 --- a/arch/x86/events/intel/bts.c +++ b/arch/x86/events/intel/bts.c @@ -80,54 +78,54 @@ 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(struct_size(bb, 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 +133,25 @@ 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 +166,7 @@ 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 +182,16 @@ 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 +203,9 @@ 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 +216,7 @@ 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 +230,17 @@ 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 +259,13 @@ 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 +304,27 @@ 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 +380,19 @@ 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 +401,10 @@ 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 +429,8 @@ 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 +443,7 @@ 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 +460,7 @@ 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 +483,8 @@ 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 +492,26 @@ 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