kernel/linux.git/arch/powerpc/include/asm/tlbflush.h, branch linux-4.4.y

powerpc/mm: don't do tlbie for updatepp request with NO HPTE fault

2014-12-05T05:26:15+00:00

upatepp can get called for a nohpte fault when we find from the linux page table that the translation was hashed before. In that case we are sure that there is no existing translation, hence we could avoid doing tlbie. We could possibly race with a parallel fault filling the TLB. But that should be ok because updatepp is only ever relaxing permissions. We also look at linux pte permission bits when filling hash pte permission bits. We also hold the linux pte busy bits while inserting/updating a hashpte entry, hence a paralle update of linux pte is not possible. On the other hand mprotect involves ptep_modify_prot_start which cause a hpte invalidate and not updatepp. Performance number: We use randbox_access_bench written by Anton. Kernel with THP disabled and smaller hash page table size. 86.60% random_access_b [kernel.kallsyms] [k] .native_hpte_updatepp 2.10% random_access_b random_access_bench [.] doit 1.99% random_access_b [kernel.kallsyms] [k] .do_raw_spin_lock 1.85% random_access_b [kernel.kallsyms] [k] .native_hpte_insert 1.26% random_access_b [kernel.kallsyms] [k] .native_flush_hash_range 1.18% random_access_b [kernel.kallsyms] [k] .__delay 0.69% random_access_b [kernel.kallsyms] [k] .native_hpte_remove 0.37% random_access_b [kernel.kallsyms] [k] .clear_user_page 0.34% random_access_b [kernel.kallsyms] [k] .__hash_page_64K 0.32% random_access_b [kernel.kallsyms] [k] fast_exception_return 0.30% random_access_b [kernel.kallsyms] [k] .hash_page_mm With Fix: 27.54% random_access_b random_access_bench [.] doit 22.90% random_access_b [kernel.kallsyms] [k] .native_hpte_insert 5.76% random_access_b [kernel.kallsyms] [k] .native_hpte_remove 5.20% random_access_b [kernel.kallsyms] [k] fast_exception_return 5.12% random_access_b [kernel.kallsyms] [k] .__hash_page_64K 4.80% random_access_b [kernel.kallsyms] [k] .hash_page_mm 3.31% random_access_b [kernel.kallsyms] [k] data_access_common 1.84% random_access_b [kernel.kallsyms] [k] .trace_hardirqs_on_caller Signed-off-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman

powerpc/mm/thp: Use tlbiel if possible

2014-12-02T03:10:11+00:00

If we know that user address space has never executed on other cpus we could use tlbiel. Signed-off-by: Aneesh Kumar K.V Signed-off-by: Benjamin Herrenschmidt

powerpc/mm/thp: Remove code duplication

2014-12-02T03:10:10+00:00

Rename invalidate_old_hpte to flush_hash_hugepage and use that in other places. Signed-off-by: Aneesh Kumar K.V Signed-off-by: Benjamin Herrenschmidt

powerpc: Replace __get_cpu_var uses

2014-11-03T01:12:32+00:00

This still has not been merged and now powerpc is the only arch that does not have this change. Sorry about missing linuxppc-dev before. V2->V2 - Fix up to work against 3.18-rc1 __get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. At the end of the patch set all uses of __get_cpu_var have been removed so the macro is removed too. The patch set includes passes over all arches as well. Once these operations are used throughout then specialized macros can be defined in non -x86 arches as well in order to optimize per cpu access by f.e. using a global register that may be set to the per cpu base. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Cc: Benjamin Herrenschmidt CC: Paul Mackerras Signed-off-by: Christoph Lameter [mpe: Fix build errors caused by set/or_softirq_pending(), and rework assignment in __set_breakpoint() to use memcpy().] Signed-off-by: Michael Ellerman

powerpc/THP: Implement transparent hugepages for ppc64

2013-06-21T06:01:53+00:00

We now have pmd entries covering 16MB range and the PMD table double its original size. We use the second half of the PMD table to deposit the pgtable (PTE page). The depoisted PTE page is further used to track the HPTE information. The information include [ secondary group | 3 bit hidx | valid ]. We use one byte per each HPTE entry. With 16MB hugepage and 64K HPTE we need 256 entries and with 4K HPTE we need 4096 entries. Both will fit in a 4K PTE page. On hugepage invalidate we need to walk the PTE page and invalidate all valid HPTEs. This patch implements necessary arch specific functions for THP support and also hugepage invalidate logic. These PMD related functions are intentionally kept similar to their PTE counter-part. Signed-off-by: Aneesh Kumar K.V Signed-off-by: Benjamin Herrenschmidt

powerpc/mm: Make some of the PGTABLE_RANGE dependency explicit

2012-09-17T06:31:53+00:00

slice array size and slice mask size depend on PGTABLE_RANGE. Reviewed-by: Paul Mackerras Signed-off-by: Aneesh Kumar K.V Signed-off-by: Benjamin Herrenschmidt

powerpc/mm: Convert virtual address to vpn

2012-09-17T06:31:49+00:00

This patch convert different functions to take virtual page number instead of virtual address. Virtual page number is virtual address shifted right by VPN_SHIFT (12) bits. This enable us to have an address range of upto 76 bits. Reviewed-by: Paul Mackerras Signed-off-by: Aneesh Kumar K.V Signed-off-by: Benjamin Herrenschmidt

powerpc/mm: Standardise on MMU_NO_CONTEXT

2011-04-20T06:59:20+00:00

Use MMU_NO_CONTEXT as the initialiser for mm_context.id on nohash and hash64. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt

powerpc/mm: Make low level TLB flush ops on BookE take additional args

2009-08-20T00:12:41+00:00

We need to pass down whether the page is direct or indirect and we'll need to pass the page size to _tlbil_va and _tlbivax_bcast We also add a new low level _tlbil_pid_noind() which does a TLB flush by PID but avoids flushing indirect entries if possible This implements those new prototypes but defines them with inlines or macros so that no additional arguments are actually passed on current processors. Signed-off-by: Benjamin Herrenschmidt

powerpc/mm: Split low level tlb invalidate for nohash processors

2008-12-21T03:21:16+00:00

Currently, the various forms of low level TLB invalidations are all implemented in misc_32.S for 32-bit processors, in a fairly scary mess of #ifdef's and with interesting duplication such as a whole bunch of code for FSL _tlbie and _tlbia which are no longer used. This moves things around such that _tlbie is now defined in hash_low_32.S and is only used by the 32-bit hash code, and all nohash CPUs use the various _tlbil_* forms that are now moved to a new file, tlb_nohash_low.S. I moved all the definitions for that stuff out of include/asm/tlbflush.h as they are really internal mm stuff, into mm/mmu_decl.h The code should have no functional changes. I kept some variants inline for trivial forms on things like 40x and 8xx. Signed-off-by: Benjamin Herrenschmidt Acked-by: Kumar Gala Signed-off-by: Paul Mackerras