The patch titled
Alter get_order() so that it can make use of ilog2() on a constant
has been added to the -mm tree. Its filename is
alter-get_order-so-that-it-can-make-use-of-ilog2-on-a-constant.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: Alter get_order() so that it can make use of ilog2() on a constant
From: David Howells <dhowells@xxxxxxxxxx>
Alter get_order() so that it can make use of ilog2() on a constant to produce
a constant value, retaining the ability for an arch to override it in the
non-const case.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/asm-generic/page.h | 14 ----------
include/linux/log2.h | 45 +++++++++++++++++++++++++++++++++++
2 files changed, 45 insertions(+), 14 deletions(-)
diff -puN include/asm-generic/page.h~alter-get_order-so-that-it-can-make-use-of-ilog2-on-a-constant include/asm-generic/page.h
--- a/include/asm-generic/page.h~alter-get_order-so-that-it-can-make-use-of-ilog2-on-a-constant
+++ a/include/asm-generic/page.h
@@ -6,20 +6,6 @@
#include <linux/compiler.h>
-/* Pure 2^n version of get_order */
-static __inline__ __attribute_const__ int get_order(unsigned long size)
-{
- int order;
-
- size = (size - 1) >> (PAGE_SHIFT - 1);
- order = -1;
- do {
- size >>= 1;
- order++;
- } while (size);
- return order;
-}
-
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
diff -puN include/linux/log2.h~alter-get_order-so-that-it-can-make-use-of-ilog2-on-a-constant include/linux/log2.h
--- a/include/linux/log2.h~alter-get_order-so-that-it-can-make-use-of-ilog2-on-a-constant
+++ a/include/linux/log2.h
@@ -25,6 +25,7 @@ int ____ilog2_NaN(void);
* non-constant log of base 2 calculators
* - the arch may override these in asm/bitops.h if they can be implemented
* more efficiently than using fls() and fls64()
+ * - the arch is not required to handle n==0 if implementing the fallback
*/
#ifndef ARCH_HAS_ILOG2_U32
static inline __attribute__((const))
@@ -42,6 +43,36 @@ int __ilog2_u64(u64 n)
}
#endif
+/*
+ * non-const pure 2^n version of get_order
+ * - the arch may override these in asm/bitops.h if they can be implemented
+ * more efficiently than using the arch log2 routines
+ * - we use the non-const log2() instead if the arch has defined one suitable
+ */
+#ifndef ARCH_HAS_GET_ORDER
+static inline __attribute__((const))
+int __get_order(unsigned long size, int page_shift)
+{
+#if BITS_PER_LONG == 32 && defined(ARCH_HAS_ILOG2_U32)
+ int order = __ilog2_u32(size) - page_shift;
+ return order >= 0 ? order : 0;
+#elif BITS_PER_LONG == 64 && defined(ARCH_HAS_ILOG2_U64)
+ int order = __ilog2_u64(size) - page_shift;
+ return order >= 0 ? order : 0;
+#else
+ int order;
+
+ size = (size - 1) >> (page_shift - 1);
+ order = -1;
+ do {
+ size >>= 1;
+ order++;
+ } while (size);
+ return order;
+#endif
+}
+#endif
+
/**
* ilog2_u32 - log of base 2 of 32-bit unsigned value
* @n - parameter
@@ -185,4 +216,18 @@ int __ilog2_u64(u64 n)
#define ilog2(n) ilog2_u64(n)
#endif
+/**
+ * get_order - calculate log2(pages) to hold a block of the specified size
+ * @n - size
+ *
+ * calculate allocation order based on the current page size
+ * - this can be used to initialise global variables from constant data
+ */
+#define get_order(n) \
+( \
+ __builtin_constant_p(n) ? \
+ ((n < (1UL << PAGE_SHIFT)) ? 0 : ilog2(n) - PAGE_SHIFT) : \
+ __get_order(n, PAGE_SHIFT) \
+ )
+
#endif /* _LINUX_LOG2_H */
_
Patches currently in -mm which might be from dhowells@xxxxxxxxxx are
git-block.patch
git-block-hack.patch
git-gfs2.patch
git-nfs.patch
nfs-replace-null-dentries-that-appear-in-readdirs-list-2.patch
mm-tracking-shared-dirty-pages-nommu-fix-2.patch
binfmt_elf-consistently-use-loff_t.patch
frv-use-the-generic-irq-stuff.patch
frv-improve-frvs-use-of-generic-irq-handling.patch
frv-permit-__do_irq-to-be-dispensed-with.patch
frv-fix-fls-to-handle-bit-31-being-set-correctly.patch
frv-implement-fls64.patch
frv-optimise-ffs.patch
nommu-check-that-access_process_vm-has-a-valid-target.patch
nommu-set-bdi-capabilities-for-dev-mem-and-dev-kmem.patch
nommu-set-bdi-capabilities-for-dev-mem-and-dev-kmem-tidy.patch
nommu-use-find_vma-rather-than-reimplementing-a-vma-search.patch
check-if-start-address-is-in-vma-region-in-nommu-function-get_user_pages.patch
nommu-check-vma-protections.patch
nommu-permit-ptrace-to-ignore-non-prot_write-vmas-in-nommu-mode.patch
nommu-implement-proc-pid-maps-for-nommu.patch
nommu-order-the-per-mm_struct-vma-list.patch
nommu-make-mremap-partially-work-for-nommu-kernels.patch
nommu-add-docs-about-shared-memory.patch
nommu-make-futexes-work-under-nommu-conditions.patch
nommu-make-futexes-work-under-nommu-conditions-doc.patch
nommu-move-the-fallback-arch_vma_name-to-a-sensible-place.patch
nommu-move-the-fallback-arch_vma_name-to-a-sensible-place-fix.patch
afs-add-lock-annotations-to-afs_proc_cell_servers_startstop.patch
elf_fdpic_core_dump-dont-take-tasklist_lock.patch
simplify-update_times-avoid-jiffies-jiffies_64-aliasing-problem-2.patch
lib-rwsemc-un-inline-rwsem_down_failed_common.patch
implement-a-general-integer-log2-facility-in-the-kernel.patch
alter-get_order-so-that-it-can-make-use-of-ilog2-on-a-constant.patch
alter-roundup_pow_of_two-so-that-it-can-make-use-of-ilog2-on-a-constant.patch
provide-ilog2-fallbacks-for-powerpc.patch
kill-wall_jiffies.patch
reiserfs-make-sure-all-dentries-refs-are-released-before-calling-kill_block_super-try-2.patch
fs-cache-provide-a-filesystem-specific-syncable-page-bit.patch
fs-cache-generic-filesystem-caching-facility.patch
fs-cache-release-page-private-in-failed-readahead.patch
fs-cache-release-page-private-after-failed-readahead-12.patch
fs-cache-make-kafs-use-fs-cache.patch
fs-cache-make-kafs-use-fs-cache-fix.patch
fs-cache-make-kafs-use-fs-cache-12.patch
fs-cache-make-kafs-use-fs-cache-12-fix.patch
fs-cache-make-kafs-use-fs-cache-vs-streamline-generic_file_-interfaces-and-filemap.patch
nfs-use-local-caching.patch
nfs-use-local-caching-12.patch
nfs-use-local-caching-12-fix.patch
fs-cache-cachefiles-ia64-missing-copy_page-export.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem-cachefiles-printk-format-warning.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem-warning-fixes.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem-cachefiles-cachefiles_write_page-shouldnt-indicate-error-twice.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem-cachefiles-handle-enospc-on-create-mkdir-better.patch
fs-cache-cachefiles-a-cache-that-backs-onto-a-mounted-filesystem-inode-count-maintenance.patch
autofs-make-sure-all-dentries-refs-are-released-before-calling-kill_anon_super.patch
vfs-destroy-the-dentries-contributed-by-a-superblock-on-unmounting.patch
generic-ioremap_page_range-implementation-nommu-fix.patch
vfs-make-filldir_t-and-struct-kstat-deal-in-64-bit-inode-numbers.patch
vfs-make-filldir_t-and-struct-kstat-deal-in-64-bit-inode-numbers-alpha-fix.patch
nfs-represent-64-bit-fileids-as-64-bit-inode-numbers-on-32-bit-systems.patch
ecryptfs-get_sb_dev-fix.patch
ecryptfs-inode-numbering-fixes.patch
introduce-kernel_execve.patch
rename-the-provided-execve-functions-to-kernel_execve.patch
provide-kernel_execve-on-all-architectures.patch
provide-kernel_execve-on-all-architectures-fix.patch
remove-the-use-of-_syscallx-macros-in-uml.patch
sh64-remove-the-use-of-kernel-syscalls.patch
remove-remaining-errno-and-__kernel_syscalls__-references.patch
reiser4-get_sb_dev-fix.patch
mutex-subsystem-synchro-test-module.patch
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