On 10/01/2016 04:11 PM, Anton Blanchard wrote:
> From: Anton Blanchard <an...@samba.org>
>
> An hcall was recently added that does exactly what we need
> during kexec - it clears the entire MMU hash table, ignoring any
> VRMA mappings.
>
> Try it and fall back to the old method if we get a failure.
>
> On a POWER8 box with 5TB of memory, this reduces the time it takes to
> kexec a new kernel from from 4 minutes to 1 minute.
>
> Signed-off-by: Anton Blanchard <an...@samba.org>
Tested-by: Mahesh Salgaonkar <mah...@linux.vnet.ibm.com>
> ---
> arch/powerpc/include/asm/hvcall.h | 3 ++-
> arch/powerpc/platforms/pseries/lpar.c | 14 +++++++++++++-
> 2 files changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/hvcall.h
> b/arch/powerpc/include/asm/hvcall.h
> index 708edeb..489748e 100644
> --- a/arch/powerpc/include/asm/hvcall.h
> +++ b/arch/powerpc/include/asm/hvcall.h
> @@ -275,7 +275,8 @@
> #define H_COP 0x304
> #define H_GET_MPP_X 0x314
> #define H_SET_MODE 0x31C
> -#define MAX_HCALL_OPCODE H_SET_MODE
> +#define H_CLEAR_HPT 0x358
> +#define MAX_HCALL_OPCODE H_CLEAR_HPT
>
> /* H_VIOCTL functions */
> #define H_GET_VIOA_DUMP_SIZE 0x01
> diff --git a/arch/powerpc/platforms/pseries/lpar.c
> b/arch/powerpc/platforms/pseries/lpar.c
> index 86707e6..03884a8 100644
> --- a/arch/powerpc/platforms/pseries/lpar.c
> +++ b/arch/powerpc/platforms/pseries/lpar.c
> @@ -221,7 +221,7 @@ static long pSeries_lpar_hpte_remove(unsigned long
> hpte_group)
> return -1;
> }
>
> -static void pSeries_lpar_hptab_clear(void)
> +static void __pSeries_lpar_clear_hpt(void)
> {
> unsigned long size_bytes = 1UL << ppc64_pft_size;
> unsigned long hpte_count = size_bytes >> 4;
> @@ -249,6 +249,18 @@ static void pSeries_lpar_hptab_clear(void)
> &(ptes[j].pteh), &(ptes[j].ptel));
> }
> }
> +}
> +
> +static void pSeries_lpar_hptab_clear(void)
> +{
> + int rc;
> +
> + do {
> + rc = plpar_hcall_norets(H_CLEAR_HPT);
> + } while (rc == H_CONTINUE);
> +
> + if (rc != H_SUCCESS)
> + __pSeries_lpar_clear_hpt();
>
> #ifdef __LITTLE_ENDIAN__
> /*
>
