Re: [evlog-dev] [PATCH] save most recent event when the buffer overflows

When reimplementing Zhu Yi's feature on top of the revised evlog-buffer
code, we'd need to add some locking around evl_ebuf.bf_head.  In the
current implementation, only the function that drains the buffer can
advance  the bf_head pointer.  In Zhu Yi's code, cbuf_wrap advances the
bf_head pointer when discarding old records to make room for the new one.

We'd also need to adjust counting of discarded records -- but retain the
policy that we don't log an "event records dropped" message until draining
has restored significant free space to the buffer.

Jim


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  |       To:       "Zhu, Yi" <[email protected]>                                                                                                     |
  |       cc:       [email protected], Hien Q Nguyen/Beaverton/IBM@IBMUS, James Keniston/Beaverton/IBM@IBMUS,                   |
  |        [email protected]                                                                                                           |
  |       Subject:  Re: [evlog-dev] [PATCH] save most recent event when the buffer overflows                                                         |
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Hi Yi,

We are currently making a lot of changes in the kernel (i.e. Jim
re-wrote the evlog kernel buffer and combined the evl_buf.c and
evl_cmd.c files to just one file evlog.c etc...). We will release the
new kernel patch in the near future, we like to postpone this patch
until then.

Thanks for your contributions.

Hien.


Zhu, Yi wrote:
> Hi,
>
> I implemented the "saving most recent event when the buffer overflows"
feature
> (TODO list 16) for kernel 2.4.20 in below patch. Currently it is enabled
by
> selecting CONFIG_EVLOG_SAVE_RECENT when make menuconfig. I am also glad
to know
> if there is any requirement to export it as a proc interface to configure
it at
> run time.
>
>
> [SNIP]




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