08 Jan, 2009

1 commit

  • * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (24 commits)
    trivial: chack -> check typo fix in main Makefile
    trivial: Add a space (and a comma) to a printk in 8250 driver
    trivial: Fix misspelling of "firmware" in docs for ncr53c8xx/sym53c8xx
    trivial: Fix misspelling of "firmware" in powerpc Makefile
    trivial: Fix misspelling of "firmware" in usb.c
    trivial: Fix misspelling of "firmware" in qla1280.c
    trivial: Fix misspelling of "firmware" in a100u2w.c
    trivial: Fix misspelling of "firmware" in megaraid.c
    trivial: Fix misspelling of "firmware" in ql4_mbx.c
    trivial: Fix misspelling of "firmware" in acpi_memhotplug.c
    trivial: Fix misspelling of "firmware" in ipw2100.c
    trivial: Fix misspelling of "firmware" in atmel.c
    trivial: Fix misspelled firmware in Kconfig
    trivial: fix an -> a typos in documentation and comments
    trivial: fix then -> than typos in comments and documentation
    trivial: update Jesper Juhl CREDITS entry with new email
    trivial: fix singal -> signal typo
    trivial: Fix incorrect use of "loose" in event.c
    trivial: printk: fix indentation of new_text_line declaration
    trivial: rtc-stk17ta8: fix sparse warning
    ...

    Linus Torvalds
     

07 Jan, 2009

1 commit

  • radix_tree_preloads is unused outside of this file, make it static.

    Noticed by sparse:
    lib/radix-tree.c:84:1: warning: symbol 'per_cpu__radix_tree_preloads' was not declared. Should it be static?

    Signed-off-by: Harvey Harrison
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Harvey Harrison
     

06 Jan, 2009

1 commit


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
     
  • Introduce gang_lookup_slot() and gang_lookup_slot_tag() functions, which
    are used by lockless pagecache.

    Signed-off-by: Nick Piggin
    Cc: Benjamin Herrenschmidt
    Cc: Paul Mackerras
    Cc: Hugh Dickins
    Cc: "Paul E. McKenney"
    Reviewed-by: Peter Zijlstra
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     

05 Jul, 2008

1 commit

  • Remove all clameter@sgi.com addresses from the kernel tree since they will
    become invalid on June 27th. Change my maintainer email address for the
    slab allocators to cl@linux-foundation.org (which will be the new email
    address for the future).

    Signed-off-by: Christoph Lameter
    Signed-off-by: Christoph Lameter
    Cc: Pekka Enberg
    Cc: Stephen Rothwell
    Cc: Matt Mackall
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Lameter
     

13 Jun, 2008

1 commit

  • We shrink a radix tree when its root node has only one child, in the left
    most slot. The child becomes the new root node. To perform this
    operation in a manner compatible with concurrent lockless lookups, we
    atomically switch the root pointer from the parent to its child.

    However a concurrent lockless lookup may now have loaded a pointer to the
    parent (and is presently deciding what to do next). For this reason, we
    also have to keep the parent node in a valid state after shrinking the
    tree, until the next RCU grace period -- otherwise this lookup with the
    parent pointer may not do the right thing. Notably, we need to keep the
    child in the left most slot there in case that is requested by the lookup.

    This is all pretty standard RCU stuff. It is worth repeating because in
    my eagerness to obey the radix tree node constructor scheme, I had broken
    it by zeroing the radix tree node before the grace period.

    What could happen is that a lookup can load the parent pointer, then
    decide it wants to follow the left most child slot, only to find the slot
    contained NULL due to the concurrent shrinker having zeroed the parent
    node before waiting for a grace period. The lookup would return a false
    negative as a result.

    Fix it by doing that clearing in the RCU callback. I would normally want
    to rip out the constructor entirely, but radix tree nodes are one of those
    places where they make sense (only few cachelines will be touched soon
    after allocation).

    This was never actually found in any lockless pagecache testing or by the
    test harness, but by seeing the odd problem with my scalable vmap rewrite.
    I have not tickled the test harness into reproducing it yet, but I'll
    keep working at it.

    Fortunately, it is not a problem anywhere lockless pagecache is used in
    mainline kernels (pagecache probe is not a guarantee, and brd does not
    have concurrent lookups and deletes).

    Signed-off-by: Nick Piggin
    Acked-by: Peter Zijlstra
    Cc: "Paul E. McKenney"
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     

28 Apr, 2008

1 commit

  • Migrate flags must be set on slab creation as agreed upon when the antifrag
    logic was reviewed. Otherwise some slabs of a slabcache will end up in the
    unmovable and others in the reclaimable section depending on which flag was
    active when a new slab page was allocated.

    This likely slid in somehow when antifrag was merged. Remove it.

    The buffer_heads are always allocated with __GFP_RECLAIMABLE because the
    SLAB_RECLAIM_ACCOUNT option is set. The set_migrateflags() never had any
    effect there.

    Radix tree allocations are not directly reclaimable but they are allocated
    with __GFP_RECLAIMABLE set on each allocation. We now set
    SLAB_RECLAIM_ACCOUNT on radix tree slab creation making sure that radix
    tree slabs are consistently placed in the reclaimable section. Radix tree
    slabs will also be accounted as such.

    There is then no user left of set_migratepages. So remove it.

    Signed-off-by: Christoph Lameter
    Cc: Mel Gorman
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Lameter
     

06 Feb, 2008

1 commit

  • Most pagecache (and some other) radix tree insertions have the great
    opportunity to preallocate a few nodes with relaxed gfp flags. But the
    preallocation is squandered when it comes time to allocate a node, we
    default to first attempting a GFP_ATOMIC allocation -- that doesn't
    normally fail, but it can eat into atomic memory reserves that we don't
    need to be using.

    Another upshot of this is that it removes the sometimes highly contended
    zone->lock from underneath tree_lock. Pagecache insertions are always
    performed with a radix tree preload, and after this change, such a
    situation will never fall back to kmem_cache_alloc within
    radix_tree_node_alloc.

    David Miller reports seeing this allocation fail on a highly threaded
    sparc64 system:

    [527319.459981] dd: page allocation failure. order:0, mode:0x20
    [527319.460403] Call Trace:
    [527319.460568] [00000000004b71e0] __slab_alloc+0x1b0/0x6a8
    [527319.460636] [00000000004b7bbc] kmem_cache_alloc+0x4c/0xa8
    [527319.460698] [000000000055309c] radix_tree_node_alloc+0x20/0x90
    [527319.460763] [0000000000553238] radix_tree_insert+0x12c/0x260
    [527319.460830] [0000000000495cd0] add_to_page_cache+0x38/0xb0
    [527319.460893] [00000000004e4794] mpage_readpages+0x6c/0x134
    [527319.460955] [000000000049c7fc] __do_page_cache_readahead+0x170/0x280
    [527319.461028] [000000000049cc88] ondemand_readahead+0x208/0x214
    [527319.461094] [0000000000496018] do_generic_mapping_read+0xe8/0x428
    [527319.461152] [0000000000497948] generic_file_aio_read+0x108/0x170
    [527319.461217] [00000000004badac] do_sync_read+0x88/0xd0
    [527319.461292] [00000000004bb5cc] vfs_read+0x78/0x10c
    [527319.461361] [00000000004bb920] sys_read+0x34/0x60
    [527319.461424] [0000000000406294] linux_sparc_syscall32+0x3c/0x40

    The calltrace is significant: __do_page_cache_readahead allocates a number
    of pages with GFP_KERNEL, and hence it should have reclaimed sufficient
    memory to satisfy GFP_ATOMIC allocations. However after the list of pages
    goes to mpage_readpages, there can be significant intervals (including disk
    IO) before all the pages are inserted into the radix-tree. So the reserves
    can easily be depleted at that point. The patch is confirmed to fix the
    problem.

    Signed-off-by: Nick Piggin
    Cc: "David S. Miller"
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     

17 Oct, 2007

6 commits

  • Negative shifts are not allowed in C (the result is undefined). Same thing
    with full-width shifts.

    It works on most platforms but not on the VAX with gcc 4.0.1 (it results in an
    "operand reserved" fault).

    Shifting by more than the width of the value on the left is also not
    allowed. I think the extra '>> 1' tacked on at the end in the original
    code was an attempt to work around that. Getting rid of that is an extra
    feature of this patch.

    Here's the chapter and verse, taken from the final draft of the C99
    standard ("6.5.7 Bitwise shift operators", paragraph 3):

    "The integer promotions are performed on each of the operands. The
    type of the result is that of the promoted left operand. If the
    value of the right operand is negative or is greater than or equal
    to the width of the promoted left operand, the behavior is
    undefined."

    Thank you to Jan-Benedict Glaw, Christoph Hellwig, Maciej Rozycki, Pekka
    Enberg, Andreas Schwab, and Christoph Lameter for review. Special thanks
    to Andreas for spotting that my fix only removed half the undefined
    behaviour.

    Signed-off-by: Peter Lund
    Christoph Lameter
    Cc: Christoph Hellwig
    Cc: "Maciej W. Rozycki"
    Cc: Pekka Enberg
    Cc: Andreas Schwab
    Cc: Nick Piggin
    Cc: WU Fengguang
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Peter Lund
     
  • 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
     
  • This patch marks a number of allocations that are either short-lived such as
    network buffers or are reclaimable such as inode allocations. When something
    like updatedb is called, long-lived and unmovable kernel allocations tend to
    be spread throughout the address space which increases fragmentation.

    This patch groups these allocations together as much as possible by adding a
    new MIGRATE_TYPE. The MIGRATE_RECLAIMABLE type is for allocations that can be
    reclaimed on demand, but not moved. i.e. they can be migrated by deleting
    them and re-reading the information from elsewhere.

    Signed-off-by: Mel Gorman
    Cc: Andy Whitcroft
    Cc: Christoph Lameter
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Mel Gorman
     
  • A while back, Nick Piggin introduced a patch to reduce the node memory
    usage for small files (commit cfd9b7df4abd3257c9e381b0e445817b26a51c0c):

    -#define RADIX_TREE_MAP_SHIFT 6
    +#define RADIX_TREE_MAP_SHIFT (CONFIG_BASE_SMALL ? 4 : 6)

    Unfortunately, he didn't take into account the fact that the
    calculation of the maximum path was based on an assumption of having
    to round up:

    #define RADIX_TREE_MAX_PATH (RADIX_TREE_INDEX_BITS/RADIX_TREE_MAP_SHIFT + 2)

    So, if CONFIG_BASE_SMALL is set, you will end up with a
    RADIX_TREE_MAX_PATH that is one greater than necessary. The practical
    upshot of this is just a bit of wasted memory (one long in the
    height_to_maxindex array, an extra pre-allocated radix tree node per
    cpu, and extra stack usage in a couple of functions), but it seems
    worth getting right.

    It's also worth noting that I never build with CONFIG_BASE_SMALL.
    What I did to test this was duplicate the code in a small user-space
    program and check the results of the calculations for max path and the
    contents of the height_to_maxindex array.

    Signed-off-by: Jeff Moyer
    Acked-by: Nick Piggin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Jeff Moyer
     
  • Rather than sign direct radix-tree pointers with a special bit, sign the
    indirect one that hangs off the root. This means that, given a lookup_slot
    operation, the invalid result will be differentiated from the valid
    (previously, valid results could have the bit either set or clear).

    This does not affect slot lookups which occur under lock -- they can never
    return an invalid result. Is needed in future for lockless pagecache.

    Signed-off-by: Nick Piggin
    Acked-by: Peter Zijlstra
    Cc: Hugh Dickins
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     
  • Introduce radix_tree_next_hole(root, index, max_scan) to scan radix tree for
    the first hole. It will be used in interleaved readahead.

    The implementation is dumb and obviously correct. It can help debug(and
    document) the possible smart one in future.

    Cc: Nick Piggin
    Signed-off-by: Fengguang Wu
    Cc: Rusty Russell
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Fengguang Wu
     

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
     

14 Jul, 2007

1 commit

  • XFS filestreams functionality uses radix trees and the preload
    functions. XFS can be built as a module and hence we need
    radix_tree_preload() exported. radix_tree_preload_end() is a
    static inline, so it doesn't need exporting.

    Signed-Off-By: Dave Chinner
    Signed-Off-By: Tim Shimmin

    David Chinner
     

10 May, 2007

1 commit

  • Since nonboot CPUs are now disabled after tasks and devices have been
    frozen and the CPU hotplug infrastructure is used for this purpose, we need
    special CPU hotplug notifications that will help the CPU-hotplug-aware
    subsystems distinguish normal CPU hotplug events from CPU hotplug events
    related to a system-wide suspend or resume operation in progress. This
    patch introduces such notifications and causes them to be used during
    suspend and resume transitions. It also changes all of the
    CPU-hotplug-aware subsystems to take these notifications into consideration
    (for now they are handled in the same way as the corresponding "normal"
    ones).

    [oleg@tv-sign.ru: cleanups]
    Signed-off-by: Rafael J. Wysocki
    Cc: Gautham R Shenoy
    Cc: Pavel Machek
    Signed-off-by: Oleg Nesterov
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Rafael J. Wysocki
     

08 Dec, 2006

3 commits

  • There was lots of #ifdef noise in the kernel due to hotcpu_notifier(fn,
    prio) not correctly marking 'fn' as used in the !HOTPLUG_CPU case, and thus
    generating compiler warnings of unused symbols, hence forcing people to add
    #ifdefs.

    the compiler can skip truly unused functions just fine:

    text data bss dec hex filename
    1624412 728710 3674856 6027978 5bfaca vmlinux.before
    1624412 728710 3674856 6027978 5bfaca vmlinux.after

    [akpm@osdl.org: topology.c fix]
    Signed-off-by: Ingo Molnar
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Ingo Molnar
     
  • Make radix tree lookups safe to be performed without locks. Readers are
    protected against nodes being deleted by using RCU based freeing. Readers
    are protected against new node insertion by using memory barriers to ensure
    the node itself will be properly written before it is visible in the radix
    tree.

    Each radix tree node keeps a record of their height (above leaf nodes).
    This height does not change after insertion -- when the radix tree is
    extended, higher nodes are only inserted in the top. So a lookup can take
    the pointer to what is *now* the root node, and traverse down it even if
    the tree is concurrently extended and this node becomes a subtree of a new
    root.

    "Direct" pointers (tree height of 0, where root->rnode points directly to
    the data item) are handled by using the low bit of the pointer to signal
    whether rnode is a direct pointer or a pointer to a radix tree node.

    When a reader wants to traverse the next branch, they will take a copy of
    the pointer. This pointer will be either NULL (and the branch is empty) or
    non-NULL (and will point to a valid node).

    [akpm@osdl.org: cleanups]
    [Lee.Schermerhorn@hp.com: bugfixes, comments, simplifications]
    [clameter@sgi.com: build fix]
    Signed-off-by: Nick Piggin
    Cc: "Paul E. McKenney"
    Signed-off-by: Lee Schermerhorn
    Cc: Christoph Lameter
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     
  • 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
     

11 Oct, 2006

1 commit


26 Jun, 2006

1 commit


23 Jun, 2006

3 commits

  • The comment states: 'Setting a tag on a not-present item is a BUG.' Hence
    if 'index' is larger than the maxindex; the item _cannot_ be presen; it
    should also be a BUG.

    Also, this allows the following statement (assume a fresh tree):

    radix_tree_tag_set(root, 16, 1);

    to fail silently, but when preceded by:

    radix_tree_insert(root, 32, item);

    it would BUG, because the height has been extended by the insert.

    In neither case was 16 present.

    Signed-off-by: Peter Zijlstra
    Acked-by: Nick Piggin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Peter Zijlstra
     
  • Reduce radix tree node memory usage by about a factor of 4 for small files
    (< 64K). There are pointer traversal and memory usage costs for large
    files with dense pagecache.

    Signed-off-by: Nick Piggin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     
  • The ability to have height 0 radix trees (a direct pointer to the data item
    rather than going through a full node->slot) quietly disappeared with
    old-2.6-bkcvs commit ffee171812d51652f9ba284302d9e5c5cc14bdfd. On 64-bit
    machines this causes nearly 600 bytes to be used for every gfp_mask bits.

    Simplify radix_tree_delete's complex tag clearing arrangement (which would
    become even more complex) by just falling back to tag clearing functions
    (the pagecache radix-tree never uses this path anyway, so the icache
    savings will mean it's actually a speedup).

    On my 4GB G5, this saves 8MB RAM per kernel kernel source+object tree in
    pagecache.

    Pagecache lookup, insertion, and removal speed for small files will also be
    improved.

    This makes RCU radix tree harder, but it's worth it.

    Signed-off-by: Nick Piggin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     

26 Mar, 2006

1 commit

  • Documentation changes to help radix tree users avoid overrunning the tags
    array. RADIX_TREE_TAGS moves to linux/radix-tree.h and is now known as
    RADIX_TREE_MAX_TAGS (Nick Piggin's idea). Tag parameters are changed to
    unsigned, and some comments are updated.

    Signed-off-by: Jonathan Corbet
    Cc: Nick Piggin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Jonathan Corbet
     

17 Feb, 2006

1 commit

  • If a tag is set for a node being deleted from a radix_tree, then that
    tag gets cleared from the parent of the node, even if it is set for some
    siblings of the node begin deleted.

    This patch changes the logic to include a test for any_tag_set similar
    to the logic a little futher down. Care is taken to ensure that
    'nr_cleared_tags' remains equals to the number of entries in the 'tags'
    array which are set to '0' (which means that this tag is not set in the
    tree below pathp->node, and should be cleared at pathp->node and
    possibly above.

    [ Nick says: "Linus FYI, I was able to modify the radix tree test
    harness to catch the bug and can no longer trigger it after the fix.
    Resulting code passes all other harness tests as well of course." ]

    Signed-off-by: Neil Brown
    Acked-by: Nick Piggin
    Signed-off-by: Linus Torvalds

    NeilBrown
     

09 Jan, 2006

3 commits

  • Shrink the height of a radix tree when it is partially truncated - we only do
    shrinkage of full truncation at present.

    Signed-off-by: Nick Piggin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     
  • Correctly determine the tags to be cleared in radix_tree_delete() so we
    don't keep moving up the tree clearing tags that we don't need to. For
    example, if a tag is simply not set in the deleted item, nor anywhere up
    the tree, radix_tree_delete() would attempt to clear it up the entire
    height of the tree.

    Also, tag_set() was made conditional so as not to dirty too many cachelines
    high up in the radix tree. Instead, put this logic into
    radix_tree_tag_set().

    Signed-off-by: Nick Piggin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     
  • Introduce helper any_tag_set() rather than repeat the same code sequence 4
    times.

    Signed-off-by: Nick Piggin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     

07 Nov, 2005

1 commit

  • Reiser4 uses radix trees to solve a trouble reiser4_readdir has serving nfs
    requests.

    Unfortunately, radix tree api lacks an operation suitable for modifying
    existing entry. This patch adds radix_tree_lookup_slot which returns pointer
    to found item within the tree. That location can be then updated.

    Both Nick and Christoph Lameter have patches which need this as well.

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

    Hans Reiser
     

09 Oct, 2005

1 commit

  • - added typedef unsigned int __nocast gfp_t;

    - replaced __nocast uses for gfp flags with gfp_t - it gives exactly
    the same warnings as far as sparse is concerned, doesn't change
    generated code (from gcc point of view we replaced unsigned int with
    typedef) and documents what's going on far better.

    Signed-off-by: Al Viro
    Signed-off-by: Linus Torvalds

    Al Viro
     

11 Sep, 2005

1 commit


08 Sep, 2005

2 commits

  • Simple patch to radix_tree_tag_get() to return different values for non
    present node and tag unset.

    The function is not used by any in-kernel callers (yet), but this
    information is definitely useful.

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

    Marcelo Tosatti
     
  • - There is frequent use of indirections in the radix code. This patch
    removes those indirections, makes the code more readable and allows
    the compilers to generate better code.

    - Removing indirections allows the removal of several casts.

    - Removing indirections allows the reduction of the radix_tree_path
    size from 3 to 2 words.

    - Use pathp-> consistently.

    - Remove unnecessary tmp variable in radix_tree_insert

    - Separate the upper layer processing from the lowest layer in __lookup()
    in order to make it easier to understand what is going on and allow
    compilers to generate better code for the loop.

    Signed-off-by: Christoph Lameter
    Cc: Nick Piggin
    Cc: James Bottomley
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Lameter
     

08 Jul, 2005

1 commit

  • Add a new section called ".data.read_mostly" for data items that are read
    frequently and rarely written to like cpumaps etc.

    If these maps are placed in the .data section then these frequenly read
    items may end up in cachelines with data is is frequently updated. In that
    case all processors in an SMP system must needlessly reload the cachelines
    again and again containing elements of those frequently used variables.

    The ability to share these cachelines will allow each cpu in an SMP system
    to keep local copies of those shared cachelines thereby optimizing
    performance.

    Signed-off-by: Alok N Kataria
    Signed-off-by: Shobhit Dayal
    Signed-off-by: Christoph Lameter
    Signed-off-by: Shai Fultheim
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Lameter
     

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