From: David Laight <David.Laight@ACULAB.COM>
To: 'Steven Rostedt' <rostedt@goodmis.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-trace-kernel@vger.kernel.org"
<linux-trace-kernel@vger.kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <akpm@linux-foundation.org>,
Tzvetomir Stoyanov <tz.stoyanov@gmail.com>,
Vincent Donnefort <vdonnefort@google.com>,
"Kent Overstreet" <kent.overstreet@gmail.com>
Subject: RE: [PATCH v5 02/15] ring-buffer: Page size per ring buffer
Date: Wed, 20 Dec 2023 08:48:02 +0000 [thread overview]
Message-ID: <84d3b41a72bd43dbb9d44921ef535c92@AcuMS.aculab.com> (raw)
In-Reply-To: <20231219185628.009147038@goodmis.org>
From: Steven Rostedt
> Sent: 19 December 2023 18:54
> From: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>
>
> 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.
>
...
> - 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);
While not new, does this really make any sense for systems with 64k pages?
Wouldn't it be better to have units of 4k?
...
> @@ -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.
Overenthusiastic global replace...
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2023-12-20 8:48 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-19 18:54 [PATCH v5 00/15] ring-buffer/tracing: Allow ring buffer to have bigger sub buffers Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 01/15] ring-buffer: Refactor ring buffer implementation Steven Rostedt
2023-12-20 9:48 ` Masami Hiramatsu
2023-12-20 12:53 ` Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 02/15] ring-buffer: Page size per ring buffer Steven Rostedt
2023-12-20 8:48 ` David Laight [this message]
2023-12-20 13:01 ` Steven Rostedt
2023-12-21 9:17 ` David Laight
2023-12-21 14:19 ` Steven Rostedt
2023-12-21 14:51 ` David Laight
2023-12-21 14:57 ` Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 03/15] ring-buffer: Add interface for configuring trace sub buffer size Steven Rostedt
2023-12-20 14:26 ` Masami Hiramatsu
2023-12-20 14:40 ` Steven Rostedt
2023-12-21 0:10 ` Masami Hiramatsu
2023-12-19 18:54 ` [PATCH v5 04/15] ring-buffer: Set new size of the ring buffer sub page Steven Rostedt
2023-12-20 16:34 ` Masami Hiramatsu
2023-12-20 16:56 ` Steven Rostedt
2023-12-21 0:11 ` Masami Hiramatsu
2023-12-19 18:54 ` [PATCH v5 05/15] ring-buffer: Read and write to ring buffers with custom sub buffer size Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 06/15] ring-buffer: Clear pages on error in ring_buffer_subbuf_order_set() failure Steven Rostedt
2023-12-20 16:23 ` Masami Hiramatsu
2023-12-20 16:30 ` Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 07/15] ring-buffer: Do no swap cpu buffers if order is different Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 08/15] ring-buffer: Make sure the spare sub buffer used for reads has same size Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 09/15] tracing: Update snapshot order along with main buffer order Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 10/15] tracing: Stop the tracing while changing the ring buffer subbuf size Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 11/15] ring-buffer: Keep the same size when updating the order Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 12/15] ring-buffer: Just update the subbuffers when changing their allocation order Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 13/15] ring-buffer: Add documentation on the buffer_subbuf_order file Steven Rostedt
2023-12-19 18:54 ` [PATCH v5 14/15] ringbuffer/selftest: Add basic selftest to test changing subbuf order Steven Rostedt
2023-12-21 0:23 ` Masami Hiramatsu
2023-12-19 18:54 ` [PATCH v5 15/15] tracing: Update subbuffer with kilobytes not page order Steven Rostedt
2023-12-21 0:26 ` Masami Hiramatsu
2023-12-21 1:57 ` Steven Rostedt
2023-12-19 22:38 ` [PATCH v5 16/15] ring-buffer: Use subbuf_order for buffer page masking Steven Rostedt
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