09 Feb, 2008

1 commit

  • Background: I've implemented 1K/2K page tables for s390. These sub-page
    page tables are required to properly support the s390 virtualization
    instruction with KVM. The SIE instruction requires that the page tables
    have 256 page table entries (pte) followed by 256 page status table entries
    (pgste). The pgstes are only required if the process is using the SIE
    instruction. The pgstes are updated by the hardware and by the hypervisor
    for a number of reasons, one of them is dirty and reference bit tracking.
    To avoid wasting memory the standard pte table allocation should return
    1K/2K (31/64 bit) and 2K/4K if the process is using SIE.

    Problem: Page size on s390 is 4K, page table size is 1K or 2K. That means
    the s390 version for pte_alloc_one cannot return a pointer to a struct
    page. Trouble is that with the CONFIG_HIGHPTE feature on x86 pte_alloc_one
    cannot return a pointer to a pte either, since that would require more than
    32 bit for the return value of pte_alloc_one (and the pte * would not be
    accessible since its not kmapped).

    Solution: The only solution I found to this dilemma is a new typedef: a
    pgtable_t. For s390 pgtable_t will be a (pte *) - to be introduced with a
    later patch. For everybody else it will be a (struct page *). The
    additional problem with the initialization of the ptl lock and the
    NR_PAGETABLE accounting is solved with a constructor pgtable_page_ctor and
    a destructor pgtable_page_dtor. The page table allocation and free
    functions need to call these two whenever a page table page is allocated or
    freed. pmd_populate will get a pgtable_t instead of a struct page pointer.
    To get the pgtable_t back from a pmd entry that has been installed with
    pmd_populate a new function pmd_pgtable is added. It replaces the pmd_page
    call in free_pte_range and apply_to_pte_range.

    Signed-off-by: Martin Schwidefsky
    Cc:
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Martin Schwidefsky
     

06 Feb, 2008

1 commit

  • (with Martin Schwidefsky )

    The pgd/pud/pmd/pte page table allocation functions get a mm_struct pointer as
    first argument. The free functions do not get the mm_struct argument. This
    is 1) asymmetrical and 2) to do mm related page table allocations the mm
    argument is needed on the free function as well.

    [kamalesh@linux.vnet.ibm.com: i386 fix]
    [akpm@linux-foundation.org: coding-syle fixes]
    Signed-off-by: Benjamin Herrenschmidt
    Signed-off-by: Martin Schwidefsky
    Cc:
    Signed-off-by: Kamalesh Babulal
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Benjamin Herrenschmidt
     

12 Oct, 2007

1 commit


22 May, 2007

1 commit

  • First thing mm.h does is including sched.h solely for can_do_mlock() inline
    function which has "current" dereference inside. By dealing with can_do_mlock()
    mm.h can be detached from sched.h which is good. See below, why.

    This patch
    a) removes unconditional inclusion of sched.h from mm.h
    b) makes can_do_mlock() normal function in mm/mlock.c
    c) exports can_do_mlock() to not break compilation
    d) adds sched.h inclusions back to files that were getting it indirectly.
    e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were
    getting them indirectly

    Net result is:
    a) mm.h users would get less code to open, read, preprocess, parse, ... if
    they don't need sched.h
    b) sched.h stops being dependency for significant number of files:
    on x86_64 allmodconfig touching sched.h results in recompile of 4083 files,
    after patch it's only 3744 (-8.3%).

    Cross-compile tested on

    all arm defconfigs, all mips defconfigs, all powerpc defconfigs,
    alpha alpha-up
    arm
    i386 i386-up i386-defconfig i386-allnoconfig
    ia64 ia64-up
    m68k
    mips
    parisc parisc-up
    powerpc powerpc-up
    s390 s390-up
    sparc sparc-up
    sparc64 sparc64-up
    um-x86_64
    x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig

    as well as my two usual configs.

    Signed-off-by: Alexey Dobriyan
    Signed-off-by: Linus Torvalds

    Alexey Dobriyan
     

19 Feb, 2007

1 commit


02 Nov, 2006

1 commit


26 Apr, 2006

1 commit


30 Oct, 2005

1 commit


05 Sep, 2005

1 commit


17 Apr, 2005

1 commit

  • Initial git repository build. I'm not bothering with the full history,
    even though we have it. We can create a separate "historical" git
    archive of that later if we want to, and in the meantime it's about
    3.2GB when imported into git - space that would just make the early
    git days unnecessarily complicated, when we don't have a lot of good
    infrastructure for it.

    Let it rip!

    Linus Torvalds