From: David Gibson <david@gibson.dropbear.id.au>
To: paulus@samba.org, aik@ozlabs.ru, benh@kernel.crashing.org
Cc: bharata@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org,
David Gibson <david@gibson.dropbear.id.au>
Subject: [RFCv2 04/25] powerpc/mm: Split hash page table sizing heuristic into a helper
Date: Tue, 8 Mar 2016 14:08:41 +1100 [thread overview]
Message-ID: <1457406542-6210-5-git-send-email-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <1457406542-6210-1-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 | 32 +++++++++++++++++++-------------
2 files changed, 22 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 fdcf9d1..da5d279 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -611,10 +611,26 @@ 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);
+
+ /* 2^11 PTEGS / 2^18 bytes is the minimum htab size permitted
+ * by the architecture */
+ 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
@@ -624,17 +640,7 @@ 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 1UL << htab_shift_for_mem_size(memblock_phys_mem_size());
}
#ifdef CONFIG_MEMORY_HOTPLUG
--
2.5.0
next prev parent reply other threads:[~2016-03-08 3:09 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-08 3:08 [RFCv2 00/25] PAPR HPT resizing, guest side & host side preliminaries David Gibson
2016-03-08 3:08 ` [RFCv2 01/25] powerpc/mm: Clean up error handling for htab_remove_mapping David Gibson
2016-03-08 3:08 ` [RFCv2 02/25] powerpc/mm: Handle removing maybe-present bolted HPTEs David Gibson
2016-03-08 3:08 ` [RFCv2 03/25] powerpc/mm: Clean up memory hotplug failure paths David Gibson
2016-03-08 3:08 ` David Gibson [this message]
2016-03-08 3:08 ` [RFCv2 05/25] pseries: Add hypercall wrappers for hash page table resizing David Gibson
2016-03-08 3:08 ` [RFCv2 06/25] pseries: Add support for hash " David Gibson
2016-03-08 3:08 ` [RFCv2 07/25] pseries: Advertise HPT resizing support via CAS David Gibson
2016-03-08 3:08 ` [RFCv2 08/25] pseries: Automatically resize HPT for memory hot add/remove David Gibson
2016-03-08 3:08 ` [RFCv2 09/25] powerpc/kvm: Corectly report KVM_CAP_PPC_ALLOC_HTAB David Gibson
2016-03-08 3:08 ` [RFCv2 10/25] powerpc/kvm: Add capability flag for hashed page table resizing David Gibson
2016-03-08 3:08 ` [RFCv2 11/25] powerpc/kvm: Rename kvm_alloc_hpt() for clarity David Gibson
2016-03-08 3:08 ` [RFCv2 12/25] powerpc/kvm: Gather HPT related variables into sub-structure David Gibson
2016-03-08 3:08 ` [RFCv2 13/25] powerpc/kvm: Don't store values derivable from HPT order David Gibson
2016-03-08 3:08 ` [RFCv2 14/25] powerpc/kvm: Split HPT allocation from activation David Gibson
2016-03-08 3:08 ` [RFCv2 15/25] powerpc/kvm: Allow KVM_PPC_ALLOCATE_HTAB ioctl() to change HPT size David Gibson
2016-03-08 3:08 ` [RFCv2 16/25] powerpc/kvm: HPT resizing stub implementation David Gibson
2016-03-08 3:08 ` [RFCv2 17/25] powerpc/kvm: Advertise availablity of HPT resizing on KVM HV David Gibson
2016-03-08 3:08 ` [RFCv2 18/25] powerpc/kvm: Outline of HPT resizing implementation David Gibson
2016-03-08 3:08 ` [RFCv2 19/25] powerpc/kbm: Allocations for HPT resizing David Gibson
2016-03-08 3:08 ` [RFCv2 20/25] powerpc/kvm: Make MMU notifier handlers more flexible David Gibson
2016-03-08 3:08 ` [RFCv2 21/25] powerpc/kvm: Make MMU notifiers HPT resize aware David Gibson
2016-03-08 3:08 ` [RFCv2 22/25] powerpc/kvm: Exclude HPT resizes when collecting the dirty log David Gibson
2016-03-08 3:09 ` [RFCv2 23/25] powerpc/kvm: Rehashing for HPT resizing David Gibson
2016-03-08 3:09 ` [RFCv2 24/25] powerpc/kvm: HPT resize pivot David Gibson
2016-03-08 3:09 ` [RFCv2 25/25] powerpc/kvm: Harvest RC bits from old HPT after HPT resize David Gibson
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