linux/mm
David Howells f0d1b0b30d [PATCH] LOG2: Implement a general integer log2 facility in the kernel
This facility provides three entry points:

	ilog2()		Log base 2 of unsigned long
	ilog2_u32()	Log base 2 of u32
	ilog2_u64()	Log base 2 of u64

These facilities can either be used inside functions on dynamic data:

	int do_something(long q)
	{
		...;
		y = ilog2(x)
		...;
	}

Or can be used to statically initialise global variables with constant values:

	unsigned n = ilog2(27);

When performing static initialisation, the compiler will report "error:
initializer element is not constant" if asked to take a log of zero or of
something not reducible to a constant.  They treat negative numbers as
unsigned.

When not dealing with a constant, they fall back to using fls() which permits
them to use arch-specific log calculation instructions - such as BSR on
x86/x86_64 or SCAN on FRV - if available.

[akpm@osdl.org: MMC fix]
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David Howells <dhowells@redhat.com>
Cc: Wojtek Kaniewski <wojtekka@toxygen.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:51 -08:00
..
allocpercpu.c [PATCH] Allow NULL pointers in percpu_free 2006-12-07 08:39:22 -08:00
backing-dev.c [PATCH] separate bdi congestion functions from queue congestion functions 2006-10-20 10:26:35 -07:00
bootmem.c [PATCH] remove EXPORT_UNUSED_SYMBOL'ed symbols 2006-12-07 08:39:44 -08:00
bounce.c [PATCH] BLOCK: Separate the bounce buffering code from the highmem code [try #6] 2006-09-30 20:32:11 +02:00
fadvise.c [PATCH] mm: change uses of f_{dentry,vfsmnt} to use f_path 2006-12-08 08:28:43 -08:00
filemap_xip.c [PATCH] mm: change uses of f_{dentry,vfsmnt} to use f_path 2006-12-08 08:28:43 -08:00
filemap.c [PATCH] mm: change uses of f_{dentry,vfsmnt} to use f_path 2006-12-08 08:28:43 -08:00
filemap.h Remove all inclusions of <linux/config.h> 2006-10-04 03:38:54 -04:00
fremap.c [PATCH] kill install_file_pte's pte_val 2006-12-07 08:39:23 -08:00
highmem.c [PATCH] BLOCK: Separate the bounce buffering code from the highmem code [try #6] 2006-09-30 20:32:11 +02:00
hugetlb.c [PATCH] mm: make compound page destructor handling explicit 2006-12-07 08:39:25 -08:00
internal.h [PATCH] mm: VM_BUG_ON 2006-09-26 08:48:44 -07:00
Kconfig Fix "can not" in Documentation and Kconfig 2006-10-03 22:53:09 +02:00
madvise.c [PATCH] Fix MADV_REMOVE protection checking 2006-04-17 18:22:18 -07:00
Makefile [PATCH] separate bdi congestion functions from queue congestion functions 2006-10-20 10:26:35 -07:00
memory_hotplug.c [PATCH] Get rid of zone_table[] 2006-12-07 08:39:20 -08:00
memory.c [PATCH] remove EXPORT_UNUSED_SYMBOL'ed symbols 2006-12-07 08:39:44 -08:00
mempolicy.c [PATCH] struct path: convert mm 2006-12-08 08:28:47 -08:00
mempool.c [PATCH] dm: work around mempool_alloc, bio_alloc_bioset deadlocks 2006-09-01 11:39:09 -07:00
migrate.c [PATCH] radix-tree: RCU lockless readside 2006-12-07 08:39:25 -08:00
mincore.c [PATCH] freepgt: sys_mincore ignore FIRST_USER_PGD_NR 2005-04-19 13:29:20 -07:00
mlock.c [PATCH] mlock cleanup 2006-12-07 08:39:22 -08:00
mmap.c [PATCH] mm: change uses of f_{dentry,vfsmnt} to use f_path 2006-12-08 08:28:43 -08:00
mmzone.c [PATCH] remove EXPORT_UNUSED_SYMBOL'ed symbols 2006-12-07 08:39:44 -08:00
mprotect.c [PATCH] paravirt: lazy mmu mode hooks.patch 2006-10-01 00:39:33 -07:00
mremap.c [PATCH] paravirt: lazy mmu mode hooks.patch 2006-10-01 00:39:33 -07:00
msync.c [PATCH] mm: msync() cleanup 2006-09-26 08:48:45 -07:00
nommu.c [PATCH] struct path: convert mm 2006-12-08 08:28:47 -08:00
oom_kill.c [PATCH] oom: less memdie 2006-12-07 08:39:20 -08:00
page_alloc.c [PATCH] LOG2: Implement a general integer log2 facility in the kernel 2006-12-08 08:28:51 -08:00
page_io.c [PATCH] swsusp: use block device offsets to identify swap locations 2006-12-07 08:39:27 -08:00
page-writeback.c [PATCH] separate bdi congestion functions from queue congestion functions 2006-10-20 10:26:35 -07:00
pdflush.c [PATCH] Add include/linux/freezer.h and move definitions from sched.h 2006-12-07 08:39:27 -08:00
prio_tree.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
readahead.c [PATCH] struct path: convert mm 2006-12-08 08:28:47 -08:00
rmap.c [PATCH] mm: more commenting on lock ordering 2006-10-20 10:26:44 -07:00
shmem_acl.c [PATCH] Fix typos in mm/shmem_acl.c 2006-10-11 11:14:23 -07:00
shmem.c [PATCH] mm: change uses of f_{dentry,vfsmnt} to use f_path 2006-12-08 08:28:43 -08:00
slab.c [PATCH] mm: fallback_alloc cpuset_zone_allowed irq fix 2006-12-08 08:28:37 -08:00
slob.c [PATCH] Make kmem_cache_destroy() return void 2006-09-27 08:26:11 -07:00
sparse.c [PATCH] numa node ids are int, page_to_nid and zone_to_nid should return int 2006-12-07 08:39:23 -08:00
swap_state.c [PATCH] lockdep: locking init debugging improvement 2006-07-03 15:27:02 -07:00
swap.c [PATCH] hotplug CPU: clean up hotcpu_notifier() use 2006-12-07 08:39:39 -08:00
swapfile.c [PATCH] mm: change uses of f_{dentry,vfsmnt} to use f_path 2006-12-08 08:28:43 -08:00
thrash.c [PATCH] make mm/thrash.c:global_faults static 2006-12-07 08:39:22 -08:00
tiny-shmem.c [PATCH] struct path: convert mm 2006-12-08 08:28:47 -08:00
truncate.c [PATCH] invalidate: remove_mapping() fix 2006-10-17 08:18:43 -07:00
util.c [PATCH] slab: clean up leak tracking ifdefs a little bit 2006-10-04 07:55:13 -07:00
vmalloc.c [PATCH] Fix strange size check in __get_vm_area_node() 2006-11-16 11:43:38 -08:00
vmscan.c [PATCH] hotplug CPU: clean up hotcpu_notifier() use 2006-12-07 08:39:39 -08:00
vmstat.c [PATCH] struct seq_operations and struct file_operations constification 2006-12-07 08:39:46 -08:00