Re: [dm-devel] [PATCH] scsi_dh_rdac: Changing the memory allocation flag from GFP_KERNEL to GFP_NOIO

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Acked-by: Chandra Seetharaman <sekharan@xxxxxxxxxx>

On Tue, 2010-01-05 at 10:20 -0700, Moger, Babu wrote:
> This patch changes the memory allocation flag from GFP_KERNEL to GFP_NOIO which is more appropriate.
> 
> This was noticed by Mike Christie and Rob Evers.. 
> Mike Christie wrote:
> > Rob Evers wrote:
> >> +
> >> +static int queue_mode_select(struct scsi_device *sdev,
> >> +                activate_complete fn, void *data)
> >> +{
> >> +    struct rdac_queue_data *qdata;
> >> +    struct rdac_controller *ctlr;
> >> +
> >> +    qdata = kzalloc(sizeof(*qdata), GFP_KERNEL);
> >> +    if (!qdata)
> >> +        return SCSI_DH_RETRY;
> >> +
> >
> > It looks like this is called in the main IO path. A failed IO could cause, the path to go down,
> > then we would call this to active a new path. If the system needed to write out pages to the same
> > disk that just had the failed path so it can allocate memory then GFP_KERNEL would be bad to use here.
> > You would use a mempool and still use something like GFP_NOIO. If a mempool is not possible for some 
> > reason, then you would want to still use GFP_NOIO.
> 
> Using mempool would become bit more complex here because I cannot assume about the number of elements
> during the allocation. I would use GFP_NOIO.
> 
> CC: Mike Christie <michaelc@xxxxxxxxxxx>
> CC: Rob Evers <revers@xxxxxxxxxx>
> CC: Chandra Seetharaman <chandra.seetharaman@xxxxxxxxxx>
> Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
> 
> ---
> --- linux-2.6.33-rc2/drivers/scsi/device_handler/scsi_dh_rdac.c.orig	2010-01-05 11:49:22.000000000 -0400
> +++ linux-2.6.33-rc2/drivers/scsi/device_handler/scsi_dh_rdac.c	2010-01-05 11:53:13.000000000 -0400
> @@ -624,7 +624,7 @@ static int queue_mode_select(struct scsi
>  	struct rdac_queue_data *qdata;
>  	struct rdac_controller *ctlr;
> 
> -	qdata = kzalloc(sizeof(*qdata), GFP_KERNEL);
> +	qdata = kzalloc(sizeof(*qdata), GFP_NOIO);
>  	if (!qdata)
>  		return SCSI_DH_RETRY;
> 
> 
> 
> 
> --
> dm-devel mailing list
> dm-devel@xxxxxxxxxx
> https://www.redhat.com/mailman/listinfo/dm-devel

--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [SCSI Target Devel]     [Linux SCSI Target Infrastructure]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Linux IIO]     [Samba]     [Device Mapper]
  Powered by Linux