The patch titled
LOG2: Alter get_order() so that it can make use of ilog2() on a constant
has been added to the -mm tree. Its filename is
log2-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: LOG2: 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: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/asm-generic/page.h | 38 +++++++++++++++++++++++++++++++----
1 file changed, 34 insertions(+), 4 deletions(-)
diff -puN include/asm-generic/page.h~log2-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~log2-alter-get_order-so-that-it-can-make-use-of-ilog2-on-a-constant
+++ a/include/asm-generic/page.h
@@ -4,21 +4,51 @@
#ifdef __KERNEL__
#ifndef __ASSEMBLY__
-#include <linux/compiler.h>
+#include <linux/log2.h>
-/* Pure 2^n version of get_order */
-static __inline__ __attribute_const__ int get_order(unsigned long size)
+/*
+ * 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);
+ size = (size - 1) >> (page_shift - 1);
order = -1;
do {
size >>= 1;
order++;
} while (size);
return order;
+#endif
}
+#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 /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
_
Patches currently in -mm which might be from dhowells@xxxxxxxxxx are
origin.patch
i386-irqs-build-fix.patch
irq_reqs-export-__irq_regs.patch
um-irq-changes-break-build.patch
x86_64-irq_regs-fix.patch
nfs-represent-64-bit-fileids-as-64-bit-inode-numbers-on-32-bit-systems.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-kconfig-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
nfs-use-local-caching-kconfig-fix.patch
nfs-use-local-caching-configh.patch
add-missing-page_copy-export-for-ppc-and-powerpc.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-fscache-fix-gfp_t-sparse-annotations.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
fscache-kconfig-tidying.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
afs-amend-the-afs-configuration-options.patch
reiser4-get_sb_dev-fix.patch
log2-implement-a-general-integer-log2-facility-in-the-kernel.patch
log2-alter-roundup_pow_of_two-so-that-it-can-use-a-ilog2-on-a-constant.patch
log2-alter-get_order-so-that-it-can-make-use-of-ilog2-on-a-constant.patch
log2-provide-ilog2-fallbacks-for-powerpc.patch
mutex-subsystem-synchro-test-module.patch
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