linux/lib/bitmap.c, branch v2.6.26

cpumask: remove bitmap_scnprintf_len and cpumask_scnprintf_len

2008-05-13T15:02:25Z

They aren't used. They were briefly used as part of some other patches to provide an alternative format for displaying some /proc and /sys cpumasks. They probably should have been removed when those other patches were dropped, in favor of a different solution. Signed-off-by: Paul Jackson Cc: "Mike Travis" Cc: "Bert Wesarg" Cc: Alexey Dobriyan Cc: WANG Cong Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mempolicy: add bitmap_onto() and bitmap_fold() operations

2008-04-28T15:58:19Z

The following adds two more bitmap operators, bitmap_onto() and bitmap_fold(), with the usual cpumask and nodemask wrappers. The bitmap_onto() operator computes one bitmap relative to another. If the n-th bit in the origin mask is set, then the m-th bit of the destination mask will be set, where m is the position of the n-th set bit in the relative mask. The bitmap_fold() operator folds a bitmap into a second that has bit m set iff the input bitmap has some bit n set, where m == n mod sz, for the specified sz value. There are two substantive changes between this patch and its predecessor bitmap_relative: 1) Renamed bitmap_relative() to be bitmap_onto(). 2) Added bitmap_fold(). The essential motivation for bitmap_onto() is to provide a mechanism for converting a cpuset-relative CPU or Node mask to an absolute mask. Cpuset relative masks are written as if the current task were in a cpuset whose CPUs or Nodes were just the consecutive ones numbered 0..N-1, for some N. The bitmap_onto() operator is provided in anticipation of adding support for the first such cpuset relative mask, by the mbind() and set_mempolicy() system calls, using a planned flag of MPOL_F_RELATIVE_NODES. These bitmap operators (and their nodemask wrappers, in particular) will be used in code that converts the user specified cpuset relative memory policy to a specific system node numbered policy, given the current mems_allowed of the tasks cpuset. Such cpuset relative mempolicies will address two deficiencies of the existing interface between cpusets and mempolicies: 1) A task cannot at present reliably establish a cpuset relative mempolicy because there is an essential race condition, in that the tasks cpuset may be changed in between the time the task can query its cpuset placement, and the time the task can issue the applicable mbind or set_memplicy system call. 2) A task cannot at present establish what cpuset relative mempolicy it would like to have, if it is in a smaller cpuset than it might have mempolicy preferences for, because the existing interface only allows specifying mempolicies for nodes currently allowed by the cpuset. Cpuset relative mempolicies are useful for tasks that don't distinguish particularly between one CPU or Node and another, but only between how many of each are allowed, and the proper placement of threads and memory pages on the various CPUs and Nodes available. The motivation for the added bitmap_fold() can be seen in the following example. Let's say an application has specified some mempolicies that presume 16 memory nodes, including say a mempolicy that specified MPOL_F_RELATIVE_NODES (cpuset relative) nodes 12-15. Then lets say that application is crammed into a cpuset that only has 8 memory nodes, 0-7. If one just uses bitmap_onto(), this mempolicy, mapped to that cpuset, would ignore the requested relative nodes above 7, leaving it empty of nodes. That's not good; better to fold the higher nodes down, so that some nodes are included in the resulting mapped mempolicy. In this case, the mempolicy nodes 12-15 are taken modulo 8 (the weight of the mems_allowed of the confining cpuset), resulting in a mempolicy specifying nodes 4-7. Signed-off-by: Paul Jackson Signed-off-by: David Rientjes Cc: Christoph Lameter Cc: Andi Kleen Cc: Mel Gorman Cc: Lee Schermerhorn Cc: Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

cpumask: add cpumask_scnprintf_len function

2008-04-19T17:44:58Z

Add a new function cpumask_scnprintf_len() to return the number of characters needed to display "len" cpumask bits. The current method of allocating NR_CPUS bytes is incorrect as what's really needed is 9 characters per 32-bit word of cpumask bits (8 hex digits plus the seperator [','] or the terminating NULL.) This function provides the caller the means to allocate the correct string length. Cc: Paul Jackson Signed-off-by: Mike Travis Signed-off-by: Ingo Molnar

Fix bitmap_scnlistprintf for empty masks

2007-11-05T23:12:32Z

When a bitmap is empty bitmap_scnlistprintf() would leave the buffer uninitialized. Set it to an empty string in this case. I didn't see any in normal kernel callers hitting this, but some custom debug code of mine did. Signed-off-by: Andi Kleen Acked-by: Paul Jackson Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] kernel-doc fixes for 2.6.20-git15 (non-drivers)

2007-03-01T22:53:37Z

Fix kernel-doc warnings in 2.6.20-git15 (lib/, mm/, kernel/, include/). Signed-off-by: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Numerous fixes to kernel-doc info in source files.

2007-02-11T18:51:32Z

A variety of (mostly) innocuous fixes to the embedded kernel-doc content in source files, including: * make multi-line initial descriptions single line * denote some function names, constants and structs as such * change erroneous opening '/*' to '/**' in a few places * reword some text for clarity Signed-off-by: Robert P. J. Day Cc: "Randy.Dunlap" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] bitmap: parse input from kernel and user buffers

2006-10-11T18:14:22Z

lib/bitmap.c:bitmap_parse() is a library function that received as input a user buffer. This seemed to have originated from the way the write_proc function of the /proc filesystem operates. This has been reworked to not use kmalloc and eliminates a lot of get_user() overhead by performing one access_ok before using __get_user(). We need to test if we are in kernel or user space (is_user) and access the buffer differently. We cannot use __get_user() to access kernel addresses in all cases, for example in architectures with separate address space for kernel and user. This function will be useful for other uses as well; for example, taking input for /sysfs instead of /proc, so it was changed to accept kernel buffers. We have this use for the Linux UWB project, as part as the upcoming bandwidth allocator code. Only a few routines used this function and they were changed too. Signed-off-by: Reinette Chatre Signed-off-by: Inaky Perez-Gonzalez Cc: Paul Jackson Cc: Joe Korty Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] kernel-doc for lib/bitmap.c

2006-06-25T17:01:20Z

Make corrections/fixes to kernel-doc in lib/bitmap.c and include it in DocBook template. Signed-off-by: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] bitops: hweight() related cleanup

2006-03-26T16:57:15Z

By defining generic hweight*() routines - hweight64() will be defined on all architectures - hweight_long() will use architecture optimized hweight32() or hweight64() I found two possible cleanups by these reasons. Signed-off-by: Akinobu Mita Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] bitmap: region restructuring

2006-03-24T15:33:20Z

Restructure the bitmap_*_region() operations, to avoid code duplication. Also reduces binary text size by about 100 bytes (ia64 arch). The original Bottomley bitmap_*_region patch added about 1000 bytes of compiled kernel text (ia64). The Mundt multiword extension added another 600 bytes, and this restructuring patch gets back about 100 bytes. But the real motivation was the reduced amount of duplicated code. Tested by Paul Mundt using <= BITS_PER_LONG as well as power of 2 aligned multiword spanning allocations. Signed-off-by: Paul Mundt Signed-off-by: Paul Jackson Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds