linux/include
Mel Gorman 5c0e306647 Fix corruption of memmap on IA64 SPARSEMEM when mem_section is not a power of 2
There are problems in the use of SPARSEMEM and pageblock flags that causes
problems on ia64.

The first part of the problem is that units are incorrect in
SECTION_BLOCKFLAGS_BITS computation.  This results in a map_section's
section_mem_map being treated as part of a bitmap which isn't good.  This
was evident with an invalid virtual address when mem_init attempted to free
bootmem pages while relinquishing control from the bootmem allocator.

The second part of the problem occurs because the pageblock flags bitmap is
be located with the mem_section.  The SECTIONS_PER_ROOT computation using
sizeof (mem_section) may not be a power of 2 depending on the size of the
bitmap.  This renders masks and other such things not power of 2 base.
This issue was seen with SPARSEMEM_EXTREME on ia64.  This patch moves the
bitmap outside of mem_section and uses a pointer instead in the
mem_section.  The bitmaps are allocated when the section is being
initialised.

Note that sparse_early_usemap_alloc() does not use alloc_remap() like
sparse_early_mem_map_alloc().  The allocation required for the bitmap on
x86, the only architecture that uses alloc_remap is typically smaller than
a cache line.  alloc_remap() pads out allocations to the cache size which
would be a needless waste.

Credit to Bob Picco for identifying the original problem and effecting a
fix for the SECTION_BLOCKFLAGS_BITS calculation.  Credit to Andy Whitcroft
for devising the best way of allocating the bitmaps only when required for
the section.

[wli@holomorphy.com: warning fix]
Signed-off-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: William Irwin <bill.irwin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 09:43:00 -07:00
..
acpi
asm-alpha
asm-arm Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm 2007-10-15 16:08:50 -07:00
asm-avr32 x86: optimize page faults like all other achitectures and kill notifier cruft 2007-10-16 09:42:50 -07:00
asm-blackfin Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2007-10-15 13:41:39 -07:00
asm-cris
asm-frv frv: missing casts in cmpxchg() 2007-10-14 12:41:51 -07:00
asm-generic flush icache before set_pte() on ia64: flush icache at set_pte 2007-10-16 09:42:59 -07:00
asm-h8300
asm-ia64 flush icache before set_pte() on ia64: flush icache at set_pte 2007-10-16 09:42:59 -07:00
asm-m32r
asm-m68k m68k: Export cachectl.h 2007-10-13 09:41:03 -07:00
asm-m68knommu
asm-mips move a few definitions to au1000_xxs1500.c 2007-10-16 09:42:50 -07:00
asm-parisc
asm-powerpc ppc64: SPARSEMEM_VMEMMAP support 2007-10-16 09:42:51 -07:00
asm-ppc
asm-s390 x86: optimize page faults like all other achitectures and kill notifier cruft 2007-10-16 09:42:50 -07:00
asm-sh x86: optimize page faults like all other achitectures and kill notifier cruft 2007-10-16 09:42:50 -07:00
asm-sh64 Merge git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh64-2.6 2007-10-13 09:50:26 -07:00
asm-sparc [SPARC32]: Add irqflags.h to sparc32 and use it from generic code. 2007-10-13 21:53:11 -07:00
asm-sparc64 SPARC64: SPARSEMEM_VMEMMAP support 2007-10-16 09:42:51 -07:00
asm-um
asm-v850
asm-x86 x86_64: SPARSEMEM_VMEMMAP 2M page size support 2007-10-16 09:42:51 -07:00
asm-xtensa
crypto [CRYPTO] sha: Add header file for SHA definitions 2007-10-10 16:55:50 -07:00
keys
linux Fix corruption of memmap on IA64 SPARSEMEM when mem_section is not a power of 2 2007-10-16 09:43:00 -07:00
math-emu
media v4l: copy_to_user() is not a good method name 2007-10-13 09:58:59 -07:00
mtd
net [IPV6]: Replace sk_buff ** with sk_buff * in input handlers 2007-10-15 12:50:28 -07:00
pcmcia pcmcia: use DMA_MASK_NONE for the default for all pcmcia devices 2007-10-16 09:42:50 -07:00
rdma
rxrpc
scsi Merge master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6 2007-10-15 08:19:33 -07:00
sound
video
xen
Kbuild