Commit Graph

9 Commits

Author SHA1 Message Date
Rik van Riel
8d1acce453 mm: Only flush the TLB when clearing an accessible pte
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>
2012-12-11 14:28:34 +00:00
Rik van Riel
cef23d9db6 mm,generic: only flush the local TLB in ptep_set_access_flags
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>
2012-12-11 14:28:33 +00:00
Gerald Schaefer
46dcde735c thp: introduce pmdp_invalidate()
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>
2012-10-09 16:22:29 +09:00
Gerald Schaefer
e3ebcf6438 thp: remove assumptions on pgtable_t type
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>
2012-10-09 16:22:29 +09:00
Chris Metcalf
73636b1aac arch/tile: allow building Linux with transparent huge pages enabled
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>
2012-05-25 12:48:21 -04:00
Naoya Horiguchi
d8c37c4806 thp: add HPAGE_PMD_* definitions for !CONFIG_TRANSPARENT_HUGEPAGE
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>
2012-03-21 17:55:02 -07:00
Andrew Morton
f95ba941d1 mm/pgtable-generic.c: fix CONFIG_SWAP=n build
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>
2011-01-26 10:49:58 +10:00
Andrea Arcangeli
b3697c0255 fix non-x86 build failure in pmdp_get_and_clear
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>
2011-01-16 15:05:44 -08:00
Andrea Arcangeli
e2cda32264 thp: add pmd mangling generic functions
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>
2011-01-13 17:32:40 -08:00