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2012-12-11mm: Only flush the TLB when clearing an accessible pteRik van Riel
If ptep_clear_flush() is called to clear a page table entry that is accessible anyway by the CPU, eg. a _PAGE_PROTNONE page table entry, there is no need to flush the TLB on remote CPUs. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-vm3rkzevahelwhejx5uwm8ex@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-12-11mm,generic: only flush the local TLB in ptep_set_access_flagsRik van Riel
The function ptep_set_access_flags is only ever used to upgrade access permissions to a page. That means the only negative side effect of not flushing remote TLBs is that other CPUs may incur spurious page faults, if they happen to access the same address, and still have a PTE with the old permissions cached in their TLB. Having another CPU maybe incur a spurious page fault is faster than always incurring the cost of a remote TLB flush, so replace the remote TLB flush with a purely local one. This should be safe on every architecture that correctly implements flush_tlb_fix_spurious_fault() to actually invalidate the local TLB entry that caused a page fault, as well as on architectures where the hardware invalidates TLB entries that cause page faults. In the unlikely event that you are hitting what appears to be an infinite loop of page faults, and 'git bisect' took you to this changeset, your architecture needs to implement flush_tlb_fix_spurious_fault to actually flush the TLB entry. Signed-off-by: Rik van Riel <riel@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Michel Lespinasse <walken@google.com> Cc: Ingo Molnar <mingo@kernel.org>
2012-10-09thp: introduce pmdp_invalidate()Gerald Schaefer
On s390, a valid page table entry must not be changed while it is attached to any CPU. So instead of pmd_mknotpresent() and set_pmd_at(), an IDTE operation would be necessary there. This patch introduces the pmdp_invalidate() function, to allow architecture-specific implementations. Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09thp: remove assumptions on pgtable_t typeGerald Schaefer
The thp page table pre-allocation code currently assumes that pgtable_t is of type "struct page *". This may not be true for all architectures, so this patch removes that assumption by replacing the functions prepare_pmd_huge_pte() and get_pmd_huge_pte() with two new functions that can be defined architecture-specific. It also removes two VM_BUG_ON checks for page_count() and page_mapcount() operating on a pgtable_t. Apart from the VM_BUG_ON removal, there will be no functional change introduced by this patch. Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-25arch/tile: allow building Linux with transparent huge pages enabledChris Metcalf
The change adds some infrastructure for managing tile pmd's more generally, using pte_pmd() and pmd_pte() methods to translate pmd values to and from ptes, since on TILEPro a pmd is really just a nested structure holding a pgd (aka pte). Several existing pmd methods are moved into this framework, and a whole raft of additional pmd accessors are defined that are used by the transparent hugepage framework. The tile PTE now has a "client2" bit. The bit is used to indicate a transparent huge page is in the process of being split into subpages. This change also fixes a generic bug where the return value of the generic pmdp_splitting_flush() was incorrect. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-03-21thp: add HPAGE_PMD_* definitions for !CONFIG_TRANSPARENT_HUGEPAGENaoya Horiguchi
These macros will be used in a later patch, where all usages are expected to be optimized away without #ifdef CONFIG_TRANSPARENT_HUGEPAGE. But to detect unexpected usages, we convert the existing BUG() to BUILD_BUG(). [akpm@linux-foundation.org: fix build in mm/pgtable-generic.c] Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Hillf Danton <dhillf@gmail.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-26mm/pgtable-generic.c: fix CONFIG_SWAP=n buildAndrew Morton
mips (and sparc32): In file included from arch/mips/include/asm/tlb.h:21, from mm/pgtable-generic.c:9: include/asm-generic/tlb.h: In function `tlb_flush_mmu': include/asm-generic/tlb.h:76: error: implicit declaration of function `release_pages' include/asm-generic/tlb.h: In function `tlb_remove_page': include/asm-generic/tlb.h:105: error: implicit declaration of function `page_cache_release' free_pages_and_swap_cache() and free_page_and_swap_cache() are macros which call release_pages() and page_cache_release(). The obvious fix is to include pagemap.h in swap.h, where those macros are defined. But that breaks sparc for weird reasons. So fix it within mm/pgtable-generic.c instead. Reported-by: Yoichi Yuasa <yuasa@linux-mips.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Sam Ravnborg <sam@ravnborg.org> Cc: Sergei Shtylyov <sshtylyov@mvista.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-16fix non-x86 build failure in pmdp_get_and_clearAndrea Arcangeli
pmdp_get_and_clear/pmdp_clear_flush/pmdp_splitting_flush were trapped as BUG() and they were defined only to diminish the risk of build issues on not-x86 archs and to be consistent with the generic pte methods previously defined in include/asm-generic/pgtable.h. But they are causing more trouble than they were supposed to solve, so it's simpler not to define them when THP is off. This is also correcting the export of pmdp_splitting_flush which is currently unused (x86 isn't using the generic implementation in mm/pgtable-generic.c and no other arch needs that [yet]). Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Sam Ravnborg <sam@ravnborg.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: "David S. Miller" <davem@davemloft.net> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13thp: add pmd mangling generic functionsAndrea Arcangeli
Some are needed to build but not actually used on archs not supporting transparent hugepages. Others like pmdp_clear_flush are used by x86 too. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>