- 01 5月, 2016 15 次提交
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由 Aneesh Kumar K.V 提交于
Now that the page table size is a variable, we can move these to generic pgtable.h. Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
Radix and hash MMU models support different page table sizes. Make the #defines a variable so that existing code can work with variable sizes. Slice related code is only used by hash, so use hash constants there. We will replicate some of the boundary conditions with resepct to TASK_SIZE using radix values too. Right now we do boundary condition check using hash constants. Swapper pgdir size is initialized in asm code. We select the max pgd size to keep it simple. For now we select hash pgdir. When adding radix we will switch that to radix pgdir which is 64K. BUILD_BUG_ON check which is removed is already done in hugepage_init() using MAYBE_BUILD_BUG_ON(). Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
These pte functions will remain the same between radix and hash. Move them to pgtable.h. Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
Now that we have moved book3s hash64 Linux pte bits to match Power ISA 3.0 radix pte bit positions, we move the matching pte bits to a common header. Only code movement in this patch. No functionality change. Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
I am splitting this as a separate patch to get better review. If ok we should merge this with previous patch. Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
This helps to make following hash only pte bits easier. We have kept _PAGE_CHG_MASK, _HPAGE_CHG_MASK and _PAGE_PROT_BITS as it is in this patch eventhough they use hash specific bits. Using them in radix as it is should be ok, because with radix we expect those bit positions to be zero. Only renames in this patch, no change in functionality. Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
The radix variant is going to require a flush_tlb_range(). With flush_tlb_range() added, ptep_clear_flush_young() is the same as the generic version. So drop the powerpc specific variant. Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
PowerISA 3.0 introduces two pte bits with the below meaning for radix: 00 -> Normal Memory 01 -> Strong Access Order (SAO) 10 -> Non idempotent I/O (Cache inhibited and guarded) 11 -> Tolerant I/O (Cache inhibited) We drop the existing WIMG bits in the Linux page table in favour of the above constants. We loose _PAGE_WRITETHRU with this conversion. We only use writethru via pgprot_cached_wthru() which is used by fbdev/controlfb.c which is Apple control display and also PPC32. With respect to _PAGE_COHERENCE, we have been marking hpte always coherent for some time now. htab_convert_pte_flags() always added HPTE_R_M. NOTE: KVM changes need closer review. Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
PS3 had used a PPP bit hack to implement a read only mapping in the kernel area. Since we are bolting the ioremap area, it used the pte flags _PAGE_PRESENT | _PAGE_USER to get a PPP value of 0x3 there by resulting in a read only mapping. This means the area can be accessed by user space, but kernel will never return such an address to user space. But we can do better by implementing a read only kernel mapping using PPP bits 0b110. This also allows us to do read only kernel mapping for radix in later patches. Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
PTE_RPN_SHIFT is actually page size dependent. Even though PowerISA 3.0 expects only the lower 12 bits to be zero, we will always find the pages to be PAGE_SHIFT aligned. In case of hash config, this also allows us to use the additional 3 bits to track pte specific information. We need to make sure we use these bits only for hash specific pte flags. For both 4K and 64K config, pte now can hold 57 bits address. Inorder to keep things simpler, drop PTE_RPN_SHIFT and PTE_RPN_SIZE and specify the 57 bit detail explicitly. Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
_PAGE_PRIVILEGED means the page can be accessed only by the kernel. This is done to keep pte bits similar to PowerISA 3.0 Radix PTE format. User pages are now marked by clearing _PAGE_PRIVILEGED bit. Previously we allowed the kernel to have a privileged page in the lower address range (USER_REGION). With this patch such access is denied. We also prevent a kernel access to a non-privileged page in higher address range (ie, REGION_ID != 0). Both the above access scenarios should never happen. Cc: Arnd Bergmann <arnd@arndb.de> Cc: Jeremy Kerr <jk@ozlabs.org> Cc: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Acked-by: NIan Munsie <imunsie@au1.ibm.com> Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
This splits the _PAGE_RW bit into _PAGE_READ and _PAGE_WRITE. It also removes the dependency on _PAGE_USER for implying read only. Few things to note here is that, we have read implied with write and execute permission. Hence we should always find _PAGE_READ set on hash pte fault. We still can't switch PROT_NONE to !(_PAGE_RWX). Auto numa depends on marking a prot none pte _PAGE_WRITE. (For more details look at b191f9b1 "mm: numa: preserve PTE write permissions across a NUMA hinting fault") Cc: Arnd Bergmann <arnd@arndb.de> Cc: Jeremy Kerr <jk@ozlabs.org> Cc: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Acked-by: NIan Munsie <imunsie@au1.ibm.com> Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Michael Ellerman 提交于
We can avoid doing endian conversions by using pte_raw() in pxx_same(). The swap of the constant (_PAGE_HPTEFLAGS) should be done at compile time by the compiler. Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
Traditionally Power server machines have used the Hashed Page Table MMU mode. In this mode Linux manages its own tree of nested page tables, aka. "the Linux page tables", which are not used by the hardware directly, and software loads translations into the hash page table for use by the hardware. Power ISA 3.0 defines a new MMU mode, known as Radix Tree Translation, where the hardware can directly operate on the Linux page tables. However the hardware requires that the page tables be in big endian format. To accommodate this, switch the pgtable types to __be64 and add appropriate endian conversions. Because we will be supporting a single kernel binary that boots using either radix or hash mode, we always store the Linux page tables big endian, even in hash mode where they are not actually used by the hardware. Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> [mpe: Fix sparse errors, flesh out change log] Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
pmd_hugepage_update() is inside #ifdef CONFIG_TRANSPARENT_HUGEPAGE. THP can only be enabled if PPC_BOOK3S_64=y && PPC_64K_PAGES=y, aka. hash64. On hash64 we always define PTE_ATOMIC_UPDATES to 1, meaning the #ifdef in pmd_hugepage_update() is unnecessary, so drop it. That is also the only use of PTE_ATOMIC_UPDATES in any of the hash code, meaning we no longer need to #define it at all in the hash headers. Note it's still #defined and used in the nohash code. Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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- 03 3月, 2016 1 次提交
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由 Aneesh Kumar K.V 提交于
This is needed so that we can support both hash and radix page table using single kernel. Radix kernel uses a 4 level table. We now use physical address in upper page table tree levels. Even though they are aligned to their size, for the masked bits we use the bit positions as per PowerISA 3.0. Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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- 29 2月, 2016 6 次提交
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由 Paul Mackerras 提交于
This moves the _PAGE_SPECIAL and _PAGE_SOFT_DIRTY bits in the Linux PTE on 64-bit Book 3S systems to bit positions which are designated for software use in the radix PTE format used by PowerISA v3.0 CPUs in radix mode. Signed-off-by: NPaul Mackerras <paulus@samba.org> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Paul Mackerras 提交于
This moves the _PAGE_EXEC, _PAGE_RW and _PAGE_USER bits around in the Linux PTE on 64-bit Book 3S systems to correspond with the bit positions used in radix mode by PowerISA v3.0 CPUs. This also adds a _PAGE_READ bit corresponding to the read permission bit in the radix PTE. _PAGE_READ is currently unused but could possibly be used in future to improve pte_protnone(). Signed-off-by: NPaul Mackerras <paulus@samba.org> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Paul Mackerras 提交于
This moves the _PAGE_HASHPTE, _PAGE_F_GIX and _PAGE_F_SECOND fields in the Linux PTE on 64-bit Book 3S systems to the most significant byte. Of the 5 bits, one is a software-use bit and the other four are reserved bit positions in the PowerISA v3.0 radix PTE format. Using these bits is OK because these bits are all to do with tracking the HPTE(s) associated with the Linux PTE, and therefore won't be needed in radix mode. This frees up bit positions in the lower two bytes. Signed-off-by: NPaul Mackerras <paulus@samba.org> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Paul Mackerras 提交于
This changes _PAGE_PTE for 64-bit Book 3S processors from 0x1 to 0x4000_0000_0000_0000, because that bit is used as the L (leaf) bit by PowerISA v3.0 CPUs in radix mode. The "leaf" bit indicates that the PTE points to a page directly rather than another radix level, which is what the _PAGE_PTE bit means. Signed-off-by: NPaul Mackerras <paulus@samba.org> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Paul Mackerras 提交于
This changes _PAGE_PRESENT for 64-bit Book 3S processors from 0x2 to 0x8000_0000_0000_0000, because that is where PowerISA v3.0 CPUs in radix mode will expect to find it. Signed-off-by: NPaul Mackerras <paulus@samba.org> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Paul Mackerras 提交于
This changes the Linux page tables to store physical addresses rather than kernel virtual addresses in the upper levels of the tree (pgd, pud and pmd) for 64-bit Book 3S machines. This also changes the hugepd pointers used to implement hugepages when the base page size is 4k to store physical addresses rather than virtual addresses (again just for 64-bit Book3S machines). This frees up some high order bits, and will be needed with PowerISA v3.0 machines which read the page table tree in hardware in radix mode. Signed-off-by: NPaul Mackerras <paulus@samba.org> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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- 27 2月, 2016 2 次提交
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由 Paul Mackerras 提交于
This frees up bits 57-63 in the Linux PTE on 64-bit Book 3S machines. In the 4k page case, this is done just by reducing the size of the RPN field to 39 bits, giving 51-bit real addresses. In the 64k page case, we had 10 unused bits in the middle of the PTE, so this moves the RPN field down 10 bits to make use of those unused bits. This means the RPN field is now 3 bits larger at 37 bits, giving 53-bit real addresses in the normal case, or 49-bit real addresses for the special 4k PFN case. We are doing this in order to be able to move some other PTE bits into the positions where PowerISA V3.0 processors will expect to find them in radix-tree mode. Ultimately we will be able to move the RPN field to lower bit positions and make it larger. Signed-off-by: NPaul Mackerras <paulus@samba.org> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Paul Mackerras 提交于
No code changes. Signed-off-by: NPaul Mackerras <paulus@samba.org> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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- 28 1月, 2016 1 次提交
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由 Aneesh Kumar K.V 提交于
This was wrongly updated by commit 7aa9a23c ("powerpc, thp: remove infrastructure for handling splitting PMDs") during the last merge window. Fix it up. This could lead to incorrect behaviour in THP and/or mprotect(), at a minimum. Fixes: 7aa9a23c ("powerpc, thp: remove infrastructure for handling splitting PMDs") Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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- 16 1月, 2016 1 次提交
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由 Kirill A. Shutemov 提交于
With new refcounting we don't need to mark PMDs splitting. Let's drop code to handle this. pmdp_splitting_flush() is not needed too: on splitting PMD we will do pmdp_clear_flush() + set_pte_at(). pmdp_clear_flush() will do IPI as needed for fast_gup. Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 12 1月, 2016 1 次提交
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由 Hugh Dickins 提交于
Swapoff after swapping hangs on the G5, when CONFIG_CHECKPOINT_RESTORE=y but CONFIG_MEM_SOFT_DIRTY is not set. That's because the non-zero _PAGE_SWP_SOFT_DIRTY bit, added by CONFIG_HAVE_ARCH_SOFT_DIRTY=y, is not discounted when CONFIG_MEM_SOFT_DIRTY is not set: so swap ptes cannot be recognized. (I suspect that the peculiar dependence of HAVE_ARCH_SOFT_DIRTY on CHECKPOINT_RESTORE in arch/powerpc/Kconfig comes from an incomplete attempt to solve this problem.) It's true that the relationship between CONFIG_HAVE_ARCH_SOFT_DIRTY and and CONFIG_MEM_SOFT_DIRTY is too confusing, and it's true that swapoff should be made more robust; but nevertheless, fix up the powerpc ifdefs as x86_64 and s390 (which met the same problem) have them, defining the bits as 0 if CONFIG_MEM_SOFT_DIRTY is not set. Fixes: 7207f436 ("powerpc/mm: Add page soft dirty tracking") Signed-off-by: NHugh Dickins <hughd@google.com> Reviewed-by: NCyrill Gorcunov <gorcunov@openvz.org> Acked-by: NLaurent Dufour <ldufour@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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- 17 12月, 2015 1 次提交
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由 Laurent Dufour 提交于
User space checkpoint and restart tool (CRIU) needs the page's change to be soft tracked. This allows to do a pre checkpoint and then dump only touched pages. This is done by using a newly assigned PTE bit (_PAGE_SOFT_DIRTY) when the page is backed in memory, and a new _PAGE_SWP_SOFT_DIRTY bit when the page is swapped out. To introduce a new PTE _PAGE_SOFT_DIRTY bit value common to hash 4k and hash 64k pte, the bits already defined in hash-*4k.h should be shifted left by one. The _PAGE_SWP_SOFT_DIRTY bit is dynamically put after the swap type in the swap pte. A check is added to ensure that the bit is not overwritten by _PAGE_HPTEFLAGS. Signed-off-by: NLaurent Dufour <ldufour@linux.vnet.ibm.com> CC: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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- 14 12月, 2015 9 次提交
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由 Aneesh Kumar K.V 提交于
For a pte entry we will have _PAGE_PTE set. Our pte page address have a minimum alignment requirement of HUGEPD_SHIFT_MASK + 1. We use the lower 7 bits to indicate hugepd. ie. For pmd and pgd we can find: 1) _PAGE_PTE set pte -> indicate PTE 2) bits [2..6] non zero -> indicate hugepd. They also encode the size. We skip bit 1 (_PAGE_PRESENT). 3) othewise pointer to next table. Acked-by: NScott Wood <scottwood@freescale.com> Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
We support THP only with book3s_64 and 64K page size. Move THP details to hash64-64k.h to clarify the same. Acked-by: NScott Wood <scottwood@freescale.com> Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
Instead of open coding it in multiple code paths, export the helper and add more documentation. Also make sure we don't make assumption regarding pte bit position Acked-by: NScott Wood <scottwood@freescale.com> Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
No real change, only style changes Acked-by: NScott Wood <scottwood@freescale.com> Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
This free up 11 bits in pte_t. In the later patch we also change the pte_t format so that we can start supporting migration pte at pmd level. We now track 4k subpage valid bit as below If we have _PAGE_COMBO set, we override the _PAGE_F_GIX_SHIFT and _PAGE_F_SECOND. Together we have 4 bits, each of them used to indicate whether any of the 4 4k subpage in that group is valid. ie, [ group 1 bit ] [ group 2 bit ] ..... [ group 4 ] [ subpage 1 - 4] [ subpage 5- 8] ..... [ subpage 13 - 16] We still track each 4k subpage slot number and secondary hash information in the second half of pgtable_t. Removing the subpage tracking have some significant overhead on aim9 and ebizzy benchmark and to support THP with 4K subpage, we do need a pgtable_t of 4096 bytes. Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
functions which operate on pte bits are moved to hash*.h and other generic functions are moved to pgtable.h Acked-by: NScott Wood <scottwood@freescale.com> Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
This enables us to keep hash64 related bits together, and makes it easy to follow. Acked-by: NScott Wood <scottwood@freescale.com> Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
We copy only needed PTE bits define from pte-common.h to respective hash related header. This should greatly simply later patches in which we are going to change the pte format for hash config Acked-by: NScott Wood <scottwood@freescale.com> Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Aneesh Kumar K.V 提交于
Acked-by: NScott Wood <scottwood@freescale.com> Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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- 19 6月, 2015 1 次提交
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由 Aneesh Kumar K.V 提交于
Current swap encoding in pte can't support large pfns above 4TB. Change the swap encoding such that we put the swap type in the PTE bits. Also add build checks to make sure we don't overlap with HPTEFLAGS. Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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- 17 2月, 2015 1 次提交
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由 Kirill A. Shutemov 提交于
We've replaced remap_file_pages(2) implementation with emulation. Nobody creates non-linear mapping anymore. Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 13 2月, 2015 1 次提交
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由 Mel Gorman 提交于
This patch removes the NUMA PTE bits and associated helpers. As a side-effect it increases the maximum possible swap space on x86-64. One potential source of problems is races between the marking of PTEs PROT_NONE, NUMA hinting faults and migration. It must be guaranteed that a PTE being protected is not faulted in parallel, seen as a pte_none and corrupting memory. The base case is safe but transhuge has problems in the past due to an different migration mechanism and a dependance on page lock to serialise migrations and warrants a closer look. task_work hinting update parallel fault ------------------------ -------------- change_pmd_range change_huge_pmd __pmd_trans_huge_lock pmdp_get_and_clear __handle_mm_fault pmd_none do_huge_pmd_anonymous_page read? pmd_lock blocks until hinting complete, fail !pmd_none test write? __do_huge_pmd_anonymous_page acquires pmd_lock, checks pmd_none pmd_modify set_pmd_at task_work hinting update parallel migration ------------------------ ------------------ change_pmd_range change_huge_pmd __pmd_trans_huge_lock pmdp_get_and_clear __handle_mm_fault do_huge_pmd_numa_page migrate_misplaced_transhuge_page pmd_lock waits for updates to complete, recheck pmd_same pmd_modify set_pmd_at Both of those are safe and the case where a transhuge page is inserted during a protection update is unchanged. The case where two processes try migrating at the same time is unchanged by this series so should still be ok. I could not find a case where we are accidentally depending on the PTE not being cleared and flushed. If one is missed, it'll manifest as corruption problems that start triggering shortly after this series is merged and only happen when NUMA balancing is enabled. Signed-off-by: NMel Gorman <mgorman@suse.de> Tested-by: NSasha Levin <sasha.levin@oracle.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dave Jones <davej@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Rik van Riel <riel@redhat.com> Cc: Mark Brown <broonie@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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