* [PATCH] trace: Correct comments about list of pages in buffer
@ 2017-02-16 10:17 Joel Fernandes
2017-02-16 14:33 ` Steven Rostedt
0 siblings, 1 reply; 2+ messages in thread
From: Joel Fernandes @ 2017-02-16 10:17 UTC (permalink / raw)
To: linux-kernel; +Cc: Joel Fernandes, Steven Rostedt, Ingo Molnar
Comments related to list of pages in the ring buffer seem to be incorrect.
This patch corrects them.
Signed-off-by: Joel Fernandes <joelaf@google.com>
---
kernel/trace/trace.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index d7449783987a..94d508c08c7e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -262,11 +262,11 @@ unsigned long long ns2usecs(u64 nsec)
/*
* The global_trace is the descriptor that holds the tracing
* buffers for the live tracing. For each CPU, it contains
- * a link list of pages that will store trace entries. The
- * page descriptor of the pages in the memory is used to hold
- * the link list by linking the lru item in the page descriptor
- * to each of the pages in the buffer per CPU.
- *
+ * a link list of pages that will store trace entries.
+ * Each page is wrapped by a buffer_page descriptor which contains
+ * a list element used to hold the list of pages by linking with
+ * other list elements of other buffer_page descriptors (for each
+ * of the pages) in the ring buffer per CPU.
* For each active CPU there is a data field that holds the
* pages for the buffer for that CPU. Each CPU has the same number
* of pages allocated for its buffer.
--
2.11.0.483.g087da7b7c-goog
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] trace: Correct comments about list of pages in buffer
2017-02-16 10:17 [PATCH] trace: Correct comments about list of pages in buffer Joel Fernandes
@ 2017-02-16 14:33 ` Steven Rostedt
0 siblings, 0 replies; 2+ messages in thread
From: Steven Rostedt @ 2017-02-16 14:33 UTC (permalink / raw)
To: Joel Fernandes; +Cc: linux-kernel, Ingo Molnar
On Thu, 16 Feb 2017 02:17:28 -0800
Joel Fernandes <joelaf@google.com> wrote:
> Comments related to list of pages in the ring buffer seem to be incorrect.
> This patch corrects them.
>
> Signed-off-by: Joel Fernandes <joelaf@google.com>
> ---
> kernel/trace/trace.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index d7449783987a..94d508c08c7e 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -262,11 +262,11 @@ unsigned long long ns2usecs(u64 nsec)
> /*
> * The global_trace is the descriptor that holds the tracing
> * buffers for the live tracing. For each CPU, it contains
> - * a link list of pages that will store trace entries. The
> - * page descriptor of the pages in the memory is used to hold
> - * the link list by linking the lru item in the page descriptor
> - * to each of the pages in the buffer per CPU.
Wow, that's a description of the very first (and poor) implementation
of the ring buffer.
> - *
> + * a link list of pages that will store trace entries.
> + * Each page is wrapped by a buffer_page descriptor which contains
> + * a list element used to hold the list of pages by linking with
> + * other list elements of other buffer_page descriptors (for each
> + * of the pages) in the ring buffer per CPU.
Actually, this comment doesn't even belong here anymore. The code lives
elsewhere.
Want to send another patch that just nukes this?
Thanks!
-- Steve
> * For each active CPU there is a data field that holds the
> * pages for the buffer for that CPU. Each CPU has the same number
> * of pages allocated for its buffer.
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2017-02-16 10:17 [PATCH] trace: Correct comments about list of pages in buffer Joel Fernandes
2017-02-16 14:33 ` Steven Rostedt
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