13 Jan, 2011

1 commit


07 Jan, 2011

2 commits

  • Reduce some branches and memory accesses in dcache lookup by adding dentry
    flags to indicate common d_ops are set, rather than having to check them.
    This saves a pointer memory access (dentry->d_op) in common path lookup
    situations, and saves another pointer load and branch in cases where we
    have d_op but not the particular operation.

    Patched with:

    git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i

    Signed-off-by: Nick Piggin

    Nick Piggin
     
  • RCU free the struct inode. This will allow:

    - Subsequent store-free path walking patch. The inode must be consulted for
    permissions when walking, so an RCU inode reference is a must.
    - sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
    to take i_lock no longer need to take sb_inode_list_lock to walk the list in
    the first place. This will simplify and optimize locking.
    - Could remove some nested trylock loops in dcache code
    - Could potentially simplify things a bit in VM land. Do not need to take the
    page lock to follow page->mapping.

    The downsides of this is the performance cost of using RCU. In a simple
    creat/unlink microbenchmark, performance drops by about 10% due to inability to
    reuse cache-hot slab objects. As iterations increase and RCU freeing starts
    kicking over, this increases to about 20%.

    In cases where inode lifetimes are longer (ie. many inodes may be allocated
    during the average life span of a single inode), a lot of this cache reuse is
    not applicable, so the regression caused by this patch is smaller.

    The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
    however this adds some complexity to list walking and store-free path walking,
    so I prefer to implement this at a later date, if it is shown to be a win in
    real situations. I haven't found a regression in any non-micro benchmark so I
    doubt it will be a problem.

    Signed-off-by: Nick Piggin

    Nick Piggin
     

29 Oct, 2010

1 commit


23 Oct, 2010

1 commit

  • * 'vfs' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl: (30 commits)
    BKL: remove BKL from freevxfs
    BKL: remove BKL from qnx4
    autofs4: Only declare function when CONFIG_COMPAT is defined
    autofs: Only declare function when CONFIG_COMPAT is defined
    ncpfs: Lock socket in ncpfs while setting its callbacks
    fs/locks.c: prepare for BKL removal
    BKL: Remove BKL from ncpfs
    BKL: Remove BKL from OCFS2
    BKL: Remove BKL from squashfs
    BKL: Remove BKL from jffs2
    BKL: Remove BKL from ecryptfs
    BKL: Remove BKL from afs
    BKL: Remove BKL from USB gadgetfs
    BKL: Remove BKL from autofs4
    BKL: Remove BKL from isofs
    BKL: Remove BKL from fat
    BKL: Remove BKL from ext2 filesystem
    BKL: Remove BKL from do_new_mount()
    BKL: Remove BKL from cgroup
    BKL: Remove BKL from NTFS
    ...

    Linus Torvalds
     

12 Oct, 2010

1 commit


05 Oct, 2010

2 commits

  • The BKL is only used in put_super, fill_super and remount_fs that are all
    three protected by the superblocks s_umount rw_semaphore. Therefore it is
    safe to remove the BKL entirely.

    Signed-off-by: Jan Blunck
    Signed-off-by: Arnd Bergmann

    Jan Blunck
     
  • This patch is a preparation necessary to remove the BKL from do_new_mount().
    It explicitly adds calls to lock_kernel()/unlock_kernel() around
    get_sb/fill_super operations for filesystems that still uses the BKL.

    I've read through all the code formerly covered by the BKL inside
    do_kern_mount() and have satisfied myself that it doesn't need the BKL
    any more.

    do_kern_mount() is already called without the BKL when mounting the rootfs
    and in nfsctl. do_kern_mount() calls vfs_kern_mount(), which is called
    from various places without BKL: simple_pin_fs(), nfs_do_clone_mount()
    through nfs_follow_mountpoint(), afs_mntpt_do_automount() through
    afs_mntpt_follow_link(). Both later functions are actually the filesystems
    follow_link inode operation. vfs_kern_mount() is calling the specified
    get_sb function and lets the filesystem do its job by calling the given
    fill_super function.

    Therefore I think it is safe to push down the BKL from the VFS to the
    low-level filesystems get_sb/fill_super operation.

    [arnd: do not add the BKL to those file systems that already
    don't use it elsewhere]

    Signed-off-by: Jan Blunck
    Signed-off-by: Arnd Bergmann
    Cc: Matthew Wilcox
    Cc: Christoph Hellwig

    Jan Blunck
     

10 Aug, 2010

3 commits

  • AFFS does not ever wait for superblock synchronization in
    ->put_super(), ->write_super, and ->sync_fs().

    However, it should wait for synchronization in ->put_super() because
    it is about to be unmounted, in ->write_super() because this is
    periodic SB synchronization performed from a separate kernel thread,
    and in ->sync_fs() it should respect the 'wait' flag. This patch fixes
    the situation.

    Also, in ->put_super(), do not write the SB if it is not dirty.

    Tested-by: Artem Bityutskiy
    Signed-off-by: Artem Bityutskiy
    Signed-off-by: Al Viro

    Artem Bityutskiy
     
  • In 'affs_write_super()': remove ancient and wrong commented code,
    remove unneeded 'clean' variable, so the function becomes a bit
    cleaner and simpler.

    In 'affs_remount(): remove unnecessary SB dirty flag changes.

    Tested-by: Artem Bityutskiy
    Signed-off-by: Artem Bityutskiy
    Signed-off-by: Al Viro

    Artem Bityutskiy
     
  • Signed-off-by: Al Viro

    Al Viro
     

30 Mar, 2010

1 commit

  • …it slab.h inclusion from percpu.h

    percpu.h is included by sched.h and module.h and thus ends up being
    included when building most .c files. percpu.h includes slab.h which
    in turn includes gfp.h making everything defined by the two files
    universally available and complicating inclusion dependencies.

    percpu.h -> slab.h dependency is about to be removed. Prepare for
    this change by updating users of gfp and slab facilities include those
    headers directly instead of assuming availability. As this conversion
    needs to touch large number of source files, the following script is
    used as the basis of conversion.

    http://userweb.kernel.org/~tj/misc/slabh-sweep.py

    The script does the followings.

    * Scan files for gfp and slab usages and update includes such that
    only the necessary includes are there. ie. if only gfp is used,
    gfp.h, if slab is used, slab.h.

    * When the script inserts a new include, it looks at the include
    blocks and try to put the new include such that its order conforms
    to its surrounding. It's put in the include block which contains
    core kernel includes, in the same order that the rest are ordered -
    alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
    doesn't seem to be any matching order.

    * If the script can't find a place to put a new include (mostly
    because the file doesn't have fitting include block), it prints out
    an error message indicating which .h file needs to be added to the
    file.

    The conversion was done in the following steps.

    1. The initial automatic conversion of all .c files updated slightly
    over 4000 files, deleting around 700 includes and adding ~480 gfp.h
    and ~3000 slab.h inclusions. The script emitted errors for ~400
    files.

    2. Each error was manually checked. Some didn't need the inclusion,
    some needed manual addition while adding it to implementation .h or
    embedding .c file was more appropriate for others. This step added
    inclusions to around 150 files.

    3. The script was run again and the output was compared to the edits
    from #2 to make sure no file was left behind.

    4. Several build tests were done and a couple of problems were fixed.
    e.g. lib/decompress_*.c used malloc/free() wrappers around slab
    APIs requiring slab.h to be added manually.

    5. The script was run on all .h files but without automatically
    editing them as sprinkling gfp.h and slab.h inclusions around .h
    files could easily lead to inclusion dependency hell. Most gfp.h
    inclusion directives were ignored as stuff from gfp.h was usually
    wildly available and often used in preprocessor macros. Each
    slab.h inclusion directive was examined and added manually as
    necessary.

    6. percpu.h was updated not to include slab.h.

    7. Build test were done on the following configurations and failures
    were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
    distributed build env didn't work with gcov compiles) and a few
    more options had to be turned off depending on archs to make things
    build (like ipr on powerpc/64 which failed due to missing writeq).

    * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
    * powerpc and powerpc64 SMP allmodconfig
    * sparc and sparc64 SMP allmodconfig
    * ia64 SMP allmodconfig
    * s390 SMP allmodconfig
    * alpha SMP allmodconfig
    * um on x86_64 SMP allmodconfig

    8. percpu.h modifications were reverted so that it could be applied as
    a separate patch and serve as bisection point.

    Given the fact that I had only a couple of failures from tests on step
    6, I'm fairly confident about the coverage of this conversion patch.
    If there is a breakage, it's likely to be something in one of the arch
    headers which should be easily discoverable easily on most builds of
    the specific arch.

    Signed-off-by: Tejun Heo <tj@kernel.org>
    Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

    Tejun Heo
     

27 Jan, 2010

3 commits


12 Jun, 2009

4 commits

  • Add a ->sync_fs method for data integrity syncs. Factor out common code
    between affs_put_super, affs_write_super and the new affs_sync_fs into
    a helper.

    Signed-off-by: Christoph Hellwig
    Signed-off-by: Al Viro

    Christoph Hellwig
     
  • [xfs, btrfs, capifs, shmem don't need BKL, exempt]

    Signed-off-by: Alessio Igor Bogani
    Signed-off-by: Al Viro

    Alessio Igor Bogani
     
  • Push down lock_super into ->write_super instances and remove it from the
    caller.

    Following filesystem don't need ->s_lock in ->write_super and are skipped:

    * bfs, nilfs2 - no other uses of s_lock and have internal locks in
    ->write_super
    * ext2 - uses BKL in ext2_write_super and has internal calls without s_lock
    * reiserfs - no other uses of s_lock as has reiserfs_write_lock (BKL) in
    ->write_super
    * xfs - no other uses of s_lock and uses internal lock (buffer lock on
    superblock buffer) to serialize ->write_super. Also xfs_fs_write_super
    is superflous and will go away in the next merge window

    Signed-off-by: Christoph Hellwig
    Signed-off-by: Al Viro

    Christoph Hellwig
     
  • Move BKL into ->put_super from the only caller. A couple of
    filesystems had trivial enough ->put_super (only kfree and NULLing of
    s_fs_info + stuff in there) to not get any locking: coda, cramfs, efs,
    hugetlbfs, omfs, qnx4, shmem, all others got the full treatment. Most
    of them probably don't need it, but I'd rather sort that out individually.
    Preferably after all the other BKL pushdowns in that area.

    [AV: original used to move lock_super() down as well; these changes are
    removed since we don't do lock_super() at all in generic_shutdown_super()
    now]
    [AV: fuse, btrfs and xfs are known to need no damn BKL, exempt]

    Signed-off-by: Christoph Hellwig
    Signed-off-by: Al Viro

    Christoph Hellwig
     

09 May, 2009

1 commit

  • Put generic_show_options read access to s_options under rcu_read_lock,
    split save_mount_options() into "we are setting it the first time"
    (uses in foo_fill_super()) and "we are relacing and freeing the old one",
    synchronize_rcu() before kfree() in the latter.

    Signed-off-by: Al Viro

    Al Viro
     

03 Apr, 2009

1 commit


14 Nov, 2008

1 commit

  • Wrap access to task credentials so that they can be separated more easily from
    the task_struct during the introduction of COW creds.

    Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

    Change some task->e?[ug]id to task_e?[ug]id(). In some places it makes more
    sense to use RCU directly rather than a convenient wrapper; these will be
    addressed by later patches.

    Signed-off-by: David Howells
    Reviewed-by: James Morris
    Acked-by: Serge Hallyn
    Cc: Roman Zippel
    Signed-off-by: James Morris

    David Howells
     

14 Oct, 2008

1 commit

  • This is a much better version of a previous patch to make the parser
    tables constant. Rather than changing the typedef, we put the "const" in
    all the various places where its required, allowing the __initconst
    exception for nfsroot which was the cause of the previous trouble.

    This was posted for review some time ago and I believe its been in -mm
    since then.

    Signed-off-by: Steven Whitehouse
    Cc: Alexander Viro
    Signed-off-by: Linus Torvalds

    Steven Whitehouse
     

27 Jul, 2008

2 commits

  • Kmem cache passed to constructor is only needed for constructors that are
    themselves multiplexeres. Nobody uses this "feature", nor does anybody uses
    passed kmem cache in non-trivial way, so pass only pointer to object.

    Non-trivial places are:
    arch/powerpc/mm/init_64.c
    arch/powerpc/mm/hugetlbpage.c

    This is flag day, yes.

    Signed-off-by: Alexey Dobriyan
    Acked-by: Pekka Enberg
    Acked-by: Christoph Lameter
    Cc: Jon Tollefson
    Cc: Nick Piggin
    Cc: Matt Mackall
    [akpm@linux-foundation.org: fix arch/powerpc/mm/hugetlbpage.c]
    [akpm@linux-foundation.org: fix mm/slab.c]
    [akpm@linux-foundation.org: fix ubifs]
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Alexey Dobriyan
     
  • The semaphore s_bmlock is used as a mutex. Convert it to the mutex API.

    Signed-off-by: Matthias Kaehlcke
    Cc: Roman Zippel
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Matthias Kaehlcke
     

07 May, 2008

1 commit

  • - remove affs_put_inode, so preallocations aren't discared unnecessarily
    often.
    - remove affs_drop_inode, it's called with a spinlock held, so it can't
    use a mutex.
    - make i_opencnt atomic
    - avoid direct b_count manipulations
    - a few allocation failure fixes, so that these are more gracefully
    handled now.
    Signed-off-by: Roman Zippel
    Signed-off-by: Christoph Hellwig
    Signed-off-by: Al Viro

    Roman Zippel
     

29 Apr, 2008

1 commit


09 Feb, 2008

1 commit

  • Add a .show_options super operation to affs.

    Use generic_show_options() and save the complete option string in
    affs_fill_super() and affs_remount().

    Signed-off-by: Miklos Szeredi
    Cc: Roman Zippel
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Miklos Szeredi
     

08 Feb, 2008

1 commit

  • Stop the AFFS filesystem from using iget() and read_inode(). Replace
    affs_read_inode() with affs_iget(), and call that instead of iget().
    affs_iget() then uses iget_locked() directly and returns a proper error code
    instead of an inode in the event of an error.

    affs_fill_super() returns any error incurred when getting the root inode
    instead of EINVAL.

    [akpm@linux-foundation.org: coding-style fixes]
    Signed-off-by: David Howells
    Cc: Roman Zippel
    Acked-by: Christoph Hellwig
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Howells
     

17 Oct, 2007

1 commit

  • Slab constructors currently have a flags parameter that is never used. And
    the order of the arguments is opposite to other slab functions. The object
    pointer is placed before the kmem_cache pointer.

    Convert

    ctor(void *object, struct kmem_cache *s, unsigned long flags)

    to

    ctor(struct kmem_cache *s, void *object)

    throughout the kernel

    [akpm@linux-foundation.org: coupla fixes]
    Signed-off-by: Christoph Lameter
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Lameter
     

20 Jul, 2007

1 commit

  • Slab destructors were no longer supported after Christoph's
    c59def9f222d44bb7e2f0a559f2906191a0862d7 change. They've been
    BUGs for both slab and slub, and slob never supported them
    either.

    This rips out support for the dtor pointer from kmem_cache_create()
    completely and fixes up every single callsite in the kernel (there were
    about 224, not including the slab allocator definitions themselves,
    or the documentation references).

    Signed-off-by: Paul Mundt

    Paul Mundt
     

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
     

17 May, 2007

1 commit

  • SLAB_CTOR_CONSTRUCTOR is always specified. No point in checking it.

    Signed-off-by: Christoph Lameter
    Cc: David Howells
    Cc: Jens Axboe
    Cc: Steven French
    Cc: Michael Halcrow
    Cc: OGAWA Hirofumi
    Cc: Miklos Szeredi
    Cc: Steven Whitehouse
    Cc: Roman Zippel
    Cc: David Woodhouse
    Cc: Dave Kleikamp
    Cc: Trond Myklebust
    Cc: "J. Bruce Fields"
    Cc: Anton Altaparmakov
    Cc: Mark Fasheh
    Cc: Paul Mackerras
    Cc: Christoph Hellwig
    Cc: Jan Kara
    Cc: David Chinner
    Cc: "David S. Miller"
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Lameter
     

08 May, 2007

1 commit

  • I have never seen a use of SLAB_DEBUG_INITIAL. It is only supported by
    SLAB.

    I think its purpose was to have a callback after an object has been freed
    to verify that the state is the constructor state again? The callback is
    performed before each freeing of an object.

    I would think that it is much easier to check the object state manually
    before the free. That also places the check near the code object
    manipulation of the object.

    Also the SLAB_DEBUG_INITIAL callback is only performed if the kernel was
    compiled with SLAB debugging on. If there would be code in a constructor
    handling SLAB_DEBUG_INITIAL then it would have to be conditional on
    SLAB_DEBUG otherwise it would just be dead code. But there is no such code
    in the kernel. I think SLUB_DEBUG_INITIAL is too problematic to make real
    use of, difficult to understand and there are easier ways to accomplish the
    same effect (i.e. add debug code before kfree).

    There is a related flag SLAB_CTOR_VERIFY that is frequently checked to be
    clear in fs inode caches. Remove the pointless checks (they would even be
    pointless without removeal of SLAB_DEBUG_INITIAL) from the fs constructors.

    This is the last slab flag that SLUB did not support. Remove the check for
    unimplemented flags from SLUB.

    Signed-off-by: Christoph Lameter
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Lameter
     

21 Feb, 2007

1 commit

  • affs wants to truncate the inode when the last user goes away, currently it
    does that through a potentially racy i_count check in ->put_inode. But we
    already have a method that's called just after the we dropped the last
    reference, ->drop_inode. This patch implements affs_drop_inode to take
    advantage of this.

    Signed-off-by: Christoph Hellwig
    Cc: Roman Zippel
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Hellwig
     

13 Feb, 2007

1 commit


08 Dec, 2006

2 commits

  • Replace all uses of kmem_cache_t with struct kmem_cache.

    The patch was generated using the following script:

    #!/bin/sh
    #
    # Replace one string by another in all the kernel sources.
    #

    set -e

    for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do
    quilt add $file
    sed -e "1,\$s/$1/$2/g" $file >/tmp/$$
    mv /tmp/$$ $file
    quilt refresh
    done

    The script was run like this

    sh replace kmem_cache_t "struct kmem_cache"

    Signed-off-by: Christoph Lameter
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Lameter
     
  • SLAB_KERNEL is an alias of GFP_KERNEL.

    Signed-off-by: Christoph Lameter
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Lameter
     

27 Sep, 2006

2 commits

  • * Rougly half of callers already do it by not checking return value
    * Code in drivers/acpi/osl.c does the following to be sure:

    (void)kmem_cache_destroy(cache);

    * Those who check it printk something, however, slab_error already printed
    the name of failed cache.
    * XFS BUGs on failed kmem_cache_destroy which is not the decision
    low-level filesystem driver should make. Converted to ignore.

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

    Alexey Dobriyan
     
  • Conversions from kmalloc+memset to kzalloc.

    Signed-off-by: Panagiotis Issaris
    Jffs2-bit-acked-by: David Woodhouse
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Panagiotis Issaris