Nice. I've got minor nits below, and you might also want to run the patch
through checkpatch and fix up some of the whitespace warnings.
-Olof
On Tue, Sep 28, 2010 at 12:02:51PM -0500, Will Schmidt wrote:
>
> This introduces a pair of kernel parameters that can be used to disable
> the MULTITCE and BULK_REMOVE h-calls.
>
> By default, those hcalls are enabled, active, and good for throughput
> and performance. The ability to disable them will be useful for some of
> the PREEMPT_RT related investigation and work occurring on Power.
>
>
> Signed-off-by: Will Schmidt <will_schm...@vnet.ibm.com>
> cc: Olof Johansson <o...@lixom.net>
> cc: Anton Blanchard <an...@samba.org>
> cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
>
> ---
>
> v2 - Per feedback from Olof, the code is reworked to utilize kernel
> parameter runtime checks, rather than CONFIG options.
> - Added relevant change to kernel-parameters.txt
>
>
>
> diff --git a/Documentation/kernel-parameters.txt
> b/Documentation/kernel-parameters.txt
> index e2c7487..5c40801 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -426,6 +426,10 @@ and is between 256 and 4096 characters. It is defined in
> the file
> bttv.pll= See Documentation/video4linux/bttv/Insmod-options
> bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
>
> + bulk_remove=off [PPC] This parameter disables the use of the pSeries
> + firmware feature for flushing multiple hpte entries
> + at a time.
> +
> BusLogic= [HW,SCSI]
> See drivers/scsi/BusLogic.c, comment before function
> BusLogic_ParseDriverOptions().
> @@ -1499,6 +1503,10 @@ and is between 256 and 4096 characters. It is defined
> in the file
> mtdparts= [MTD]
> See drivers/mtd/cmdlinepart.c.
>
> + multitce=off [PPC] This parameter disables the use of the pSeries
> + firmware feature for updating multiple TCE entries
> + at a time.
> +
> onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
>
> Format:
> [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
> diff --git a/arch/powerpc/platforms/pseries/iommu.c
> b/arch/powerpc/platforms/pseries/iommu.c
> index 902987d..e174a2f 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -625,3 +625,19 @@ void iommu_init_early_pSeries(void)
> set_pci_dma_ops(&dma_iommu_ops);
> }
>
> +static int __init disable_multitce(char *str)
> +{
> + if (strcmp(str,"off")==0) {
> + if (firmware_has_feature(FW_FEATURE_LPAR)) {
> + if (firmware_has_feature(FW_FEATURE_MULTITCE)) {
> + printk(KERN_INFO "Disabling MULTITCE firmware
> feature\n");
> + ppc_md.tce_build = tce_build_pSeriesLP;
> + ppc_md.tce_free = tce_free_pSeriesLP;
> + powerpc_firmware_features &=
> ~FW_FEATURE_MULTITCE;
> + }
> + }
> + }
I personally prefer to keep cases like these in one if statement to save
indentation:
if (strcmp(str, "off") == 0 &&
firmware_has_feature(FW_FEATURE_LPAR) &&
firmware_has_feature(FW_FEATURE_MULTITCE)) {
<...>
}
> + return 1;
> +}
> +
> +__setup("multitce=",disable_multitce);
> diff --git a/arch/powerpc/platforms/pseries/lpar.c
> b/arch/powerpc/platforms/pseries/lpar.c
> index 0707653..82d15e7 100644
> --- a/arch/powerpc/platforms/pseries/lpar.c
> +++ b/arch/powerpc/platforms/pseries/lpar.c
> @@ -599,6 +599,19 @@ static void pSeries_lpar_flush_hash_range(unsigned long
> number, int local)
> spin_unlock_irqrestore(&pSeries_lpar_tlbie_lock, flags);
> }
>
> +static int __init disable_bulk_remove(char *str)
> +{
> + if (strcmp(str,"off")==0) {
> + if (firmware_has_feature(FW_FEATURE_BULK_REMOVE)) {
> + printk(KERN_INFO "Disabling BULK_REMOVE firmware
> feature");
> + powerpc_firmware_features &= ~FW_FEATURE_BULK_REMOVE;
> + }
> + }
Same here.
> + return 1;
> +}
> +
> +__setup("bulk_remove=",disable_bulk_remove);
> +
> void __init hpte_init_lpar(void)
> {
> ppc_md.hpte_invalidate = pSeries_lpar_hpte_invalidate;
>
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