From: David Gibson <david@gibson.dropbear.id.au>
To: paulus@samba.org, mpe@ellerman.id.au, benh@kernel.crashing.org
Cc: linuxppc-dev@lists.ozlabs.org, aik@ozlabs.ru, thuth@redhat.com,
lvivier@redhat.com, David Gibson <david@gibson.dropbear.id.au>
Subject: [RFCv2 5/9] arch/powerpc: Split hash page table sizing heuristic into a helper
Date: Fri, 29 Jan 2016 16:23:59 +1100 [thread overview]
Message-ID: <1454045043-25545-6-git-send-email-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <1454045043-25545-1-git-send-email-david@gibson.dropbear.id.au>
htab_get_table_size() either retrieve the size of the hash page table (HPT)
from the device tree - if the HPT size is determined by firmware - or
uses a heuristic to determine a good size based on RAM size if the kernel
is responsible for allocating the HPT.
To support a PAPR extension allowing resizing of the HPT, we're going to
want the memory size -> HPT size logic elsewhere, so split it out into a
helper function.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
arch/powerpc/include/asm/mmu-hash64.h | 3 +++
arch/powerpc/mm/hash_utils_64.c | 30 +++++++++++++++++-------------
2 files changed, 20 insertions(+), 13 deletions(-)
diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
index 7352d3f..cf070fd 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -607,6 +607,9 @@ static inline unsigned long get_kernel_vsid(unsigned long ea, int ssize)
context = (MAX_USER_CONTEXT) + ((ea >> 60) - 0xc) + 1;
return get_vsid(context, ea, ssize);
}
+
+unsigned htab_shift_for_mem_size(unsigned long mem_size);
+
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_MMU_HASH64_H_ */
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index e88a86e..d63f7dc 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -606,10 +606,24 @@ static int __init htab_dt_scan_pftsize(unsigned long node,
return 0;
}
-static unsigned long __init htab_get_table_size(void)
+unsigned htab_shift_for_mem_size(unsigned long mem_size)
{
- unsigned long mem_size, rnd_mem_size, pteg_count, psize;
+ unsigned memshift = __ilog2(mem_size);
+ unsigned pshift = mmu_psize_defs[mmu_virtual_psize].shift;
+ unsigned pteg_shift;
+
+ /* round mem_size up to next power of 2 */
+ if ((1UL << memshift) < mem_size)
+ memshift += 1;
+
+ /* aim for 2 pages / pteg */
+ pteg_shift = memshift - (pshift + 1);
+
+ return max(pteg_shift + 7, 18U);
+}
+static unsigned long __init htab_get_table_size(void)
+{
/* If hash size isn't already provided by the platform, we try to
* retrieve it from the device-tree. If it's not there neither, we
* calculate it now based on the total RAM size
@@ -619,17 +633,7 @@ static unsigned long __init htab_get_table_size(void)
if (ppc64_pft_size)
return 1UL << ppc64_pft_size;
- /* round mem_size up to next power of 2 */
- mem_size = memblock_phys_mem_size();
- rnd_mem_size = 1UL << __ilog2(mem_size);
- if (rnd_mem_size < mem_size)
- rnd_mem_size <<= 1;
-
- /* # pages / 2 */
- psize = mmu_psize_defs[mmu_virtual_psize].shift;
- pteg_count = max(rnd_mem_size >> (psize + 1), 1UL << 11);
-
- return pteg_count << 7;
+ return htab_shift_for_mem_size(memblock_phys_mem_size());
}
#ifdef CONFIG_MEMORY_HOTPLUG
--
2.5.0
next prev parent reply other threads:[~2016-01-29 5:23 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-29 5:23 [RFCv2 0/9] PAPR hash page table resizing (guest side) David Gibson
2016-01-29 5:23 ` [RFCv2 1/9] memblock: Don't mark memblock_phys_mem_size() as __init David Gibson
2016-02-01 5:50 ` Anshuman Khandual
2016-02-08 2:46 ` Paul Mackerras
2016-01-29 5:23 ` [RFCv2 2/9] arch/powerpc: Clean up error handling for htab_remove_mapping David Gibson
2016-02-01 5:54 ` Anshuman Khandual
2016-02-08 2:48 ` Paul Mackerras
2016-01-29 5:23 ` [RFCv2 3/9] arch/powerpc: Handle removing maybe-present bolted HPTEs David Gibson
2016-02-01 5:58 ` Anshuman Khandual
2016-02-02 1:08 ` David Gibson
2016-02-02 13:49 ` Denis Kirjanov
2016-02-08 2:54 ` Paul Mackerras
2016-02-09 0:43 ` David Gibson
2016-01-29 5:23 ` [RFCv2 4/9] arch/powerpc: Clean up memory hotplug failure paths David Gibson
2016-02-01 6:29 ` Anshuman Khandual
2016-02-02 15:04 ` Nathan Fontenot
2016-02-03 4:31 ` David Gibson
2016-02-08 5:47 ` Paul Mackerras
2016-01-29 5:23 ` David Gibson [this message]
2016-02-01 7:04 ` [RFCv2 5/9] arch/powerpc: Split hash page table sizing heuristic into a helper Anshuman Khandual
2016-02-02 1:04 ` David Gibson
2016-02-04 10:56 ` Anshuman Khandual
2016-02-08 5:57 ` Paul Mackerras
2016-01-29 5:24 ` [RFCv2 6/9] pseries: Add hypercall wrappers for hash page table resizing David Gibson
2016-02-01 7:11 ` Anshuman Khandual
2016-02-02 0:58 ` David Gibson
2016-02-04 11:11 ` Anshuman Khandual
2016-02-07 22:33 ` David Gibson
2016-02-08 5:58 ` Paul Mackerras
2016-01-29 5:24 ` [RFCv2 7/9] pseries: Add support for hash " David Gibson
2016-02-01 8:31 ` Anshuman Khandual
2016-02-01 11:04 ` David Gibson
2016-02-08 5:59 ` Paul Mackerras
2016-01-29 5:24 ` [RFCv2 8/9] pseries: Advertise HPT resizing support via CAS David Gibson
2016-02-01 8:36 ` Anshuman Khandual
2016-02-08 6:00 ` Paul Mackerras
2016-01-29 5:24 ` [RFCv2 9/9] pseries: Automatically resize HPT for memory hot add/remove David Gibson
2016-02-01 8:51 ` Anshuman Khandual
2016-02-01 10:55 ` David Gibson
2016-02-08 6:01 ` Paul Mackerras
2016-02-01 5:50 ` [RFCv2 0/9] PAPR hash page table resizing (guest side) Anshuman Khandual
2016-02-02 0:57 ` David Gibson
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