From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 96F8E17745; Tue, 26 May 2026 05:06:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779771973; cv=none; b=rLjmnHH9p/h1axf8i/N4dD1KDUK/dNdPoFAaZFnF06vXup8KfA4lo0zZ0YSzJjRVSoehxNAC5GcC1H3J8LzLOva5KQcXeb+o0YnhLs7MyX0ADVtWRpgncKiAA2DxnWEGD005Zh4q6/yXnL4OS3gy8UUIJISrFsn2bfIayh7Uj8k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779771973; c=relaxed/simple; bh=9+dvesZqHCez6C4ImG/1xrjdB0ok+iwKeIEfOLvMUVc=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=J+KVCY/YiEQ7T/eKi9xLwjgGEL4tdSSRQux3PENHbRcZoziFvi5h+FqAdQLBYzHfxwoWBGnWOzFgfBrUy4AfItgIoF45xC5RjqjUbgm+2zSYVUUidw35AtxOQdemRB7v780akKsf2clHmgsB+wWS0FX3Dm7FWdKCGxgkUK3qIhw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ad4avntu; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ad4avntu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B5AF1F00A3A; Tue, 26 May 2026 05:06:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779771972; bh=vEPpbuA9hCnZ8dvT8zTkda0SXclRyd3TxRFVCR7xy8g=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=ad4avntuP2ZomCQdCoxLLnnUdiNASJfRvJWe9lTkb/tqCYeDA+mlnJC3uZUXOGG5F CVpidv2qdQSXApd3bxWKHCWp2Z57bLFV4vKMYlXh5tleGSG+m+SPHqZ3dFIOA5YfCD ZDEvGlVRkWVpsJDErZvPiHMMPyp6HzVDTTy17g7mJ0UmXaNJbrBls4KMku7ggsr83+ SXKauVdmu1wAfijwBpMSH2zHV7+aEb90Vy8GLLt/E4ALHpaC3bdnYRS3pXLTdmKFO/ q7IkyC1Ob6Q2HvokJcu5gLRxsUldjEls5ciza9Gh++l+q/9p7TIzNuTR133u3i5BP6 qwU7Fxr8NDi/Q== Date: Tue, 26 May 2026 14:06:09 +0900 From: Masami Hiramatsu (Google) To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Ian Rogers Subject: Re: [PATCH v21 8/9] ring-buffer: Show persistent buffer dropped events in trace file Message-Id: <20260526140609.28faf45d9d347e5d748e7cf1@kernel.org> In-Reply-To: <20260522171052.006276604@kernel.org> References: <20260522170857.263969486@kernel.org> <20260522171052.006276604@kernel.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 22 May 2026 13:09:05 -0400 Steven Rostedt wrote: > @@ -7187,6 +7190,8 @@ int ring_buffer_read_page(struct trace_buffer *buffer, > local_set(&reader->entries, 0); > reader->read = 0; > data_page->data = dpage; > + if (!missed_events && rb_data_page_commit(dpage) & RB_MISSED_EVENTS) > + missed_events = -1; > > /* > * Use the real_end for the data size, > @@ -7204,10 +7209,12 @@ int ring_buffer_read_page(struct trace_buffer *buffer, > * Set a flag in the commit field if we lost events > */ > if (missed_events) { > - /* If there is room at the end of the page to save the > + /* > + * 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 (missed_events > 0 && > + buffer->subbuf_size - commit >= sizeof(missed_events)) { > memcpy(&dpage->data[commit], &missed_events, > sizeof(missed_events)); > local_add(RB_MISSED_STORED, &dpage->commit); After this line, we "add" RB_MISSED_EVENTS instead of set. In this case, does it clear the RB_MISSED_EVENTS bit because it already sets RB_MISSED_EVENTS. commit += sizeof(missed_events); } local_add(RB_MISSED_EVENTS, &bpage->commit); ^^^ here. Thanks, -- Masami Hiramatsu (Google)