>
> On 03/06/2012 06:10 PM, Zou, Yi wrote:
> >> On 03/05/2012 09:42 PM, Yi Zou wrote:
> >>> When performing a cable pull test w/ active stress I/O using fio over
> >>> a dual port Intel 82599 FCoE CNA, w/ 256LUNs on one port and about
> >> 32LUNs
> >>> on the other, it is observed that the system becomes not usable due
> to
> >>> scsi-ml being busy printing the error messages for all the failing
> >> commands.
> >>> I don't believe this problem is specific to FCoE and these commands
> are
> >>> anyway failing due to link being down (DID_NO_CONNECT), just rate-
> limit
> >>> the messages here to solve this issue.
> >>>
> >>> Signed-off-by: Yi Zou <yi.zou@xxxxxxxxx>
> >>> Cc: www.Open-FCoE.org <devel@xxxxxxxxxxxxx>
> >> Hi Zou,
> >> you shouldn't use printk_ratelimit .
> >> checkpatch says: WARNING: Prefer printk_ratelimited or
> >> pr_<level>_ratelimited to printk_ratelimit
> >> Tomas
> > Yes, I saw that when I did the checkpatch, but pratek_ratelimit()
> actually
> > serves the purpose better, as it guards the block of the several scsi
> related
> > prints that follow, and this works well particularly for this bug. For
> the worst
> > case, the shared ratelimit surpresses everything here, blk i/o error
> report
> > would still be able pick up printing something.
> >
> > If it is desired, which I doubt, I could change all scmd_printk,
> scsi_print_xxxx
> > calls to use printk_ratelimited(), seems an overkill for this to me. I
> am open
> > for a better solution.
> For a whole block of commands you can use __ratelimit, so something like
> this
> were possible:
>
> @@ -20,6 +20,7 @@
> #include <linux/delay.h>
> #include <linux/hardirq.h>
> #include <linux/scatterlist.h>
> +#include <linux/ratelimit.h>
>
> #include <scsi/scsi.h>
> #include <scsi/scsi_cmnd.h>
> @@ -745,6 +746,8 @@ void scsi_io_completion(struct scsi_cmnd *cmd,
> unsigned int good_bytes)
> enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
> ACTION_DELAYED_RETRY} action;
> char *description = NULL;
> + static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
> + DEFAULT_RATELIMIT_BURST);
>
> if (result) {
> sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
> @@ -935,7 +938,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd,
> unsigned int good_bytes)
> case ACTION_FAIL:
> /* Give up and fail the remainder of the request */
> scsi_release_buffers(cmd);
> - if (!(req->cmd_flags & REQ_QUIET)) {
> + if (!(req->cmd_flags & REQ_QUIET) && __ratelimit(&rs)) {
> if (description)
> scmd_printk(KERN_INFO, cmd, "%s\n",
> description);yi
>
This looks better, I will resend the patch, which will be pretty much the same
what you have here.
thanks.
yi
>
> >>> ---
> >>>
> >>> drivers/scsi/scsi_lib.c | 3 ++-
> >>> 1 files changed, 2 insertions(+), 1 deletions(-)
> >>>
> >>> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> >>> index b2c95db..e2128d9 100644
> >>> --- a/drivers/scsi/scsi_lib.c
> >>> +++ b/drivers/scsi/scsi_lib.c
> >>> @@ -934,7 +934,8 @@ void scsi_io_completion(struct scsi_cmnd *cmd,
> >> unsigned int good_bytes)
> >>> case ACTION_FAIL:
> >>> /* Give up and fail the remainder of the request */
> >>> scsi_release_buffers(cmd);
> >>> - if (!(req->cmd_flags & REQ_QUIET)) {
> >>> + if (!(req->cmd_flags & REQ_QUIET) &&
> >>> + printk_ratelimit()) {
> >>> if (description)
> >>> scmd_printk(KERN_INFO, cmd, "%s\n",
> >>> description);
> >>>
> >>> --
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> >> in
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> >> --
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