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| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2023-03-15 12:31:33 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-04-06 04:42:46 +0200 |
| commit | 23baf831a32c04f9a968812511540b1b3e648bf5 (patch) | |
| tree | fcaca52cefbef2707710ce057f58fb1c955a0559 /Documentation/admin-guide | |
| parent | iommu: fix MAX_ORDER usage in __iommu_dma_alloc_pages() (diff) | |
| download | linux-23baf831a32c04f9a968812511540b1b3e648bf5.tar.xz linux-23baf831a32c04f9a968812511540b1b3e648bf5.zip | |
mm, treewide: redefine MAX_ORDER sanely
MAX_ORDER currently defined as number of orders page allocator supports:
user can ask buddy allocator for page order between 0 and MAX_ORDER-1.
This definition is counter-intuitive and lead to number of bugs all over
the kernel.
Change the definition of MAX_ORDER to be inclusive: the range of orders
user can ask from buddy allocator is 0..MAX_ORDER now.
[kirill@shutemov.name: fix min() warning]
Link: https://lkml.kernel.org/r/20230315153800.32wib3n5rickolvh@box
[akpm@linux-foundation.org: fix another min_t warning]
[kirill@shutemov.name: fixups per Zi Yan]
Link: https://lkml.kernel.org/r/20230316232144.b7ic4cif4kjiabws@box.shutemov.name
[akpm@linux-foundation.org: fix underlining in docs]
Link: https://lore.kernel.org/oe-kbuild-all/202303191025.VRCTk6mP-lkp@intel.com/
Link: https://lkml.kernel.org/r/20230315113133.11326-11-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc]
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/kdump/vmcoreinfo.rst | 6 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 2 |
2 files changed, 4 insertions, 4 deletions
diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst index 86fd88492870..c18d94fa6470 100644 --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst @@ -172,7 +172,7 @@ variables. Offset of the free_list's member. This value is used to compute the number of free pages. -Each zone has a free_area structure array called free_area[MAX_ORDER]. +Each zone has a free_area structure array called free_area[MAX_ORDER + 1]. The free_list represents a linked list of free page blocks. (list_head, next|prev) @@ -189,8 +189,8 @@ Offsets of the vmap_area's members. They carry vmalloc-specific information. Makedumpfile gets the start address of the vmalloc region from this. -(zone.free_area, MAX_ORDER) ---------------------------- +(zone.free_area, MAX_ORDER + 1) +------------------------------- Free areas descriptor. User-space tools use this value to iterate the free_area ranges. MAX_ORDER is used by the zone buddy allocator. diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 6221a1d057dd..50da4f26fad5 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3969,7 +3969,7 @@ [KNL] Minimal page reporting order Format: <integer> Adjust the minimal page reporting order. The page - reporting is disabled when it exceeds (MAX_ORDER-1). + reporting is disabled when it exceeds MAX_ORDER. panic= [KNL] Kernel behaviour on panic: delay <timeout> timeout > 0: seconds before rebooting |