linux/include/asm-generic/pgtable.h, branch v2.6.37

[S390] add support for nonquiescing sske

2010-10-25T14:10:15Z

Improve performance of the sske operation by using the nonquiescing variant if the affected page has no mappings established. On machines with no support for the new sske variant the mask bit will be ignored. Signed-off-by: Martin Schwidefsky

x86, mm: Avoid unnecessary TLB flush

2010-08-23T17:04:57Z

In x86, access and dirty bits are set automatically by CPU when CPU accesses memory. When we go into the code path of below flush_tlb_fix_spurious_fault(), we already set dirty bit for pte and don't need flush tlb. This might mean tlb entry in some CPUs hasn't dirty bit set, but this doesn't matter. When the CPUs do page write, they will automatically check the bit and no software involved. On the other hand, flush tlb in below position is harmful. Test creates CPU number of threads, each thread writes to a same but random address in same vma range and we measure the total time. Under a 4 socket system, original time is 1.96s, while with the patch, the time is 0.8s. Under a 2 socket system, there is 20% time cut too. perf shows a lot of time are taking to send ipi/handle ipi for tlb flush. Signed-off-by: Shaohua Li LKML-Reference: <20100816011655.GA362@sli10-desk.sh.intel.com> Acked-by: Suresh Siddha Cc: Andrea Archangeli Signed-off-by: H. Peter Anvin

asm-generic: add dummy pgprot_noncached()

2009-06-23T12:34:30Z

Most architectures now provide a pgprot_noncached(), the remaining ones can simply use an dummy default implementation, except for cris and xtensa, which should override the default appropriately. Signed-off-by: Arnd Bergmann Cc: Jesper Nilsson Cc: Chris Zankel Cc: Magnus Damm

x86/paravirt: finish change from lazy cpu to context switch start/end

2009-03-30T06:36:01Z

Impact: fix lazy context switch API Pass the previous and next tasks into the context switch start end calls, so that the called functions can properly access the task state (esp in end_context_switch, in which the next task is not yet completely current). Signed-off-by: Jeremy Fitzhardinge Acked-by: Peter Zijlstra

x86/pvops: replace arch_enter_lazy_cpu_mode with arch_start_context_switch

2009-03-30T06:35:59Z

Impact: simplification, prepare for later changes Make lazy cpu mode more specific to context switching, so that it makes sense to do more context-switch specific things in the callbacks. Signed-off-by: Jeremy Fitzhardinge Acked-by: Peter Zijlstra

x86 PAT: change track_pfn_vma_new to take pgprot_t pointer param

2009-01-13T18:13:01Z

Impact: cleanup Change the protection parameter for track_pfn_vma_new() into a pgprot_t pointer. Subsequent patch changes the x86 PAT handling to return a compatible memtype in pgprot_t, if what was requested cannot be allowed due to conflicts. No fuctionality change in this patch. Signed-off-by: Venkatesh Pallipadi Signed-off-by: Suresh Siddha Signed-off-by: Ingo Molnar

x86: PAT: move track untrack pfnmap stubs to asm-generic

2008-12-19T23:40:30Z

Impact: Cleanup and branch hints only. Move the track and untrack pfn stub routines from memory.c to asm-generic. Also add unlikely to pfnmap related calls in fork and exit path. Signed-off-by: Venkatesh Pallipadi Signed-off-by: Suresh Siddha Signed-off-by: H. Peter Anvin

x86: PAT: add pgprot_writecombine() interface for drivers - v3

2008-12-18T21:30:16Z

Impact: New mm functionality. Add pgprot_writecombine. pgprot_writecombine will be aliased to pgprot_noncached when not supported by the architecture. Signed-off-by: Venkatesh Pallipadi Signed-off-by: Suresh Siddha Signed-off-by: H. Peter Anvin

mm: fix build on non-mmu machines

2008-07-15T20:58:40Z

Commit 1ea0704e0d aka "mm: add a ptep_modify_prot transaction abstraction" caused: | CC init/main.o |In file included from include2/asm/pgtable.h:68, | from /home/bigeasy/git/linux-2.6-m68k/include/linux/mm.h:39, | from include2/asm/uaccess.h:8, | from /home/bigeasy/git/linux-2.6-m68k/include/linux/poll.h:13, | from /home/bigeasy/git/linux-2.6-m68k/include/linux/rtc.h:113, | from /home/bigeasy/git/linux-2.6-m68k/include/linux/efi.h:19, | from /home/bigeasy/git/linux-2.6-m68k/init/main.c:43: |/linux-2.6/include/asm-generic/pgtable.h: In function '__ptep_modify_prot_start': |/linux-2.6/include/asm-generic/pgtable.h:209: error: implicit declaration of function 'ptep_get_and_clear' |/linux-2.6/include/asm-generic/pgtable.h:209: error: incompatible types in return |/linux-2.6/include/asm-generic/pgtable.h: In function '__ptep_modify_prot_commit': |/linux-2.6/include/asm-generic/pgtable.h:220: error: implicit declaration of function 'set_pte_at' |make[2]: *** [init/main.o] Error 1 |make[1]: *** [init] Error 2 |make: *** [sub-make] Error 2 on my m68knommu box. Acked-by: Jeremy Fitzhardinge Cc: Linus Torvalds Cc: Hugh Dickins Cc: Ingo Molnar Signed-off-by: Sebastian Siewior Signed-off-by: Linus Torvalds

mm: add a ptep_modify_prot transaction abstraction

2008-06-25T13:15:53Z

This patch adds an API for doing read-modify-write updates to a pte's protection bits which may race against hardware updates to the pte. After reading the pte, the hardware may asynchonously set the accessed or dirty bits on a pte, which would be lost when writing back the modified pte value. The existing technique to handle this race is to use ptep_get_and_clear() atomically fetch the old pte value and clear it in memory. This has the effect of marking the pte as non-present, which will prevent the hardware from updating its state. When the new value is written back, the pte will be present again, and the hardware can resume updating the access/dirty flags. When running in a virtualized environment, pagetable updates are relatively expensive, since they generally involve some trap into the hypervisor. To mitigate the cost of these updates, we tend to batch them. However, because of the atomic nature of ptep_get_and_clear(), it is inherently non-batchable. This new interface allows batching by giving the underlying implementation enough information to open a transaction between the read and write phases: ptep_modify_prot_start() returns the current pte value, and puts the pte entry into a state where either the hardware will not update the pte, or if it does, the updates will be preserved on commit. ptep_modify_prot_commit() writes back the updated pte, makes sure that any hardware updates made since ptep_modify_prot_start() are preserved. ptep_modify_prot_start() and _commit() must be exactly paired, and used while holding the appropriate pte lock. They do not protect against other software updates of the pte in any way. The current implementations of ptep_modify_prot_start and _commit are functionally unchanged from before: _start() uses ptep_get_and_clear() fetch the pte and zero the entry, preventing any hardware updates. _commit() simply writes the new pte value back knowing that the hardware has not updated the pte in the meantime. The only current user of this interface is mprotect Signed-off-by: Jeremy Fitzhardinge Acked-by: Linus Torvalds Acked-by: Hugh Dickins Signed-off-by: Ingo Molnar