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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2023-12-28 17:47:04 +0300
committerAndrew Morton <akpm@linux-foundation.org>2024-01-08 15:27:15 -0800
commit5e0a760b44417f7cadd79de2204d6247109558a0 (patch)
tree5f93b6d09d15cb11b0d92e8e4b98dedf1d9ab5b6 /Documentation
parentfd37721803c6e73619108f76ad2e12a9aa5fafaf (diff)
mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER
commit 23baf831a32c ("mm, treewide: redefine MAX_ORDER sanely") has changed the definition of MAX_ORDER to be inclusive. This has caused issues with code that was not yet upstream and depended on the previous definition. To draw attention to the altered meaning of the define, rename MAX_ORDER to MAX_PAGE_ORDER. Link: https://lkml.kernel.org/r/20231228144704.14033-2-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/kdump/vmcoreinfo.rst2
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt24
-rw-r--r--Documentation/networking/packet_mmap.rst14
3 files changed, 20 insertions, 20 deletions
diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst
index 3f8769e46b07..bced9e4b6e08 100644
--- a/Documentation/admin-guide/kdump/vmcoreinfo.rst
+++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst
@@ -193,7 +193,7 @@ from this.
--------------------------------
Free areas descriptor. User-space tools use this value to iterate the
-free_area ranges. MAX_ORDER is used by the zone buddy allocator.
+free_area ranges. NR_PAGE_ORDERS is used by the zone buddy allocator.
prb
---
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 65731b060e3f..8a01b8112f0b 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -970,17 +970,17 @@
buddy allocator. Bigger value increase the probability
of catching random memory corruption, but reduce the
amount of memory for normal system use. The maximum
- possible value is MAX_ORDER/2. Setting this parameter
- to 1 or 2 should be enough to identify most random
- memory corruption problems caused by bugs in kernel or
- driver code when a CPU writes to (or reads from) a
- random memory location. Note that there exists a class
- of memory corruptions problems caused by buggy H/W or
- F/W or by drivers badly programming DMA (basically when
- memory is written at bus level and the CPU MMU is
- bypassed) which are not detectable by
- CONFIG_DEBUG_PAGEALLOC, hence this option will not help
- tracking down these problems.
+ possible value is MAX_PAGE_ORDER/2. Setting this
+ parameter to 1 or 2 should be enough to identify most
+ random memory corruption problems caused by bugs in
+ kernel or driver code when a CPU writes to (or reads
+ from) a random memory location. Note that there exists
+ a class of memory corruptions problems caused by buggy
+ H/W or F/W or by drivers badly programming DMA
+ (basically when memory is written at bus level and the
+ CPU MMU is bypassed) which are not detectable by
+ CONFIG_DEBUG_PAGEALLOC, hence this option will not
+ help tracking down these problems.
debug_pagealloc=
[KNL] When CONFIG_DEBUG_PAGEALLOC is set, this parameter
@@ -4136,7 +4136,7 @@
[KNL] Minimal page reporting order
Format: <integer>
Adjust the minimal page reporting order. The page
- reporting is disabled when it exceeds MAX_ORDER.
+ reporting is disabled when it exceeds MAX_PAGE_ORDER.
panic= [KNL] Kernel behaviour on panic: delay <timeout>
timeout > 0: seconds before rebooting
diff --git a/Documentation/networking/packet_mmap.rst b/Documentation/networking/packet_mmap.rst
index 30a3be3c48f3..dca15d15feaf 100644
--- a/Documentation/networking/packet_mmap.rst
+++ b/Documentation/networking/packet_mmap.rst
@@ -263,20 +263,20 @@ the name indicates, this function allocates pages of memory, and the second
argument is "order" or a power of two number of pages, that is
(for PAGE_SIZE == 4096) order=0 ==> 4096 bytes, order=1 ==> 8192 bytes,
order=2 ==> 16384 bytes, etc. The maximum size of a
-region allocated by __get_free_pages is determined by the MAX_ORDER macro. More
-precisely the limit can be calculated as::
+region allocated by __get_free_pages is determined by the MAX_PAGE_ORDER macro.
+More precisely the limit can be calculated as::
- PAGE_SIZE << MAX_ORDER
+ PAGE_SIZE << MAX_PAGE_ORDER
In a i386 architecture PAGE_SIZE is 4096 bytes
- In a 2.4/i386 kernel MAX_ORDER is 10
- In a 2.6/i386 kernel MAX_ORDER is 11
+ In a 2.4/i386 kernel MAX_PAGE_ORDER is 10
+ In a 2.6/i386 kernel MAX_PAGE_ORDER is 11
So get_free_pages can allocate as much as 4MB or 8MB in a 2.4/2.6 kernel
respectively, with an i386 architecture.
User space programs can include /usr/include/sys/user.h and
-/usr/include/linux/mmzone.h to get PAGE_SIZE MAX_ORDER declarations.
+/usr/include/linux/mmzone.h to get PAGE_SIZE MAX_PAGE_ORDER declarations.
The pagesize can also be determined dynamically with the getpagesize (2)
system call.
@@ -324,7 +324,7 @@ Definitions:
(see /proc/slabinfo)
<pointer size> depends on the architecture -- ``sizeof(void *)``
<page size> depends on the architecture -- PAGE_SIZE or getpagesize (2)
-<max-order> is the value defined with MAX_ORDER
+<max-order> is the value defined with MAX_PAGE_ORDER
<frame size> it's an upper bound of frame's capture size (more on this later)
============== ================================================================