linux-sg2042/mm
Martin Schwidefsky 2f569afd9c CONFIG_HIGHPTE vs. sub-page page tables.
Background: I've implemented 1K/2K page tables for s390.  These sub-page
page tables are required to properly support the s390 virtualization
instruction with KVM.  The SIE instruction requires that the page tables
have 256 page table entries (pte) followed by 256 page status table entries
(pgste).  The pgstes are only required if the process is using the SIE
instruction.  The pgstes are updated by the hardware and by the hypervisor
for a number of reasons, one of them is dirty and reference bit tracking.
To avoid wasting memory the standard pte table allocation should return
1K/2K (31/64 bit) and 2K/4K if the process is using SIE.

Problem: Page size on s390 is 4K, page table size is 1K or 2K.  That means
the s390 version for pte_alloc_one cannot return a pointer to a struct
page.  Trouble is that with the CONFIG_HIGHPTE feature on x86 pte_alloc_one
cannot return a pointer to a pte either, since that would require more than
32 bit for the return value of pte_alloc_one (and the pte * would not be
accessible since its not kmapped).

Solution: The only solution I found to this dilemma is a new typedef: a
pgtable_t.  For s390 pgtable_t will be a (pte *) - to be introduced with a
later patch.  For everybody else it will be a (struct page *).  The
additional problem with the initialization of the ptl lock and the
NR_PAGETABLE accounting is solved with a constructor pgtable_page_ctor and
a destructor pgtable_page_dtor.  The page table allocation and free
functions need to call these two whenever a page table page is allocated or
freed.  pmd_populate will get a pgtable_t instead of a struct page pointer.
 To get the pgtable_t back from a pmd entry that has been installed with
pmd_populate a new function pmd_pgtable is added.  It replaces the pmd_page
call in free_pte_range and apply_to_pte_range.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:42 -08:00
..
Kconfig sh: Bump number of quicklists for SH-5. 2008-01-28 13:18:55 +09:00
Makefile Memory controller: cgroups setup 2008-02-07 08:42:18 -08:00
allocpercpu.c PERCPU : __percpu_alloc_mask() can dynamically size percpu_data storage 2008-02-06 10:41:04 -08:00
backing-dev.c mm/backing-dev.c: fix percpu_counter_destroy call bug in bdi_init 2007-12-05 09:21:18 -08:00
bootmem.c Introduce flags for reserve_bootmem() 2008-02-07 08:42:25 -08:00
bounce.c block: Initial support for data-less (or empty) barrier support 2007-10-16 11:03:56 +02:00
dmapool.c pool: Improve memory usage for devices which can't cross boundaries 2007-12-04 10:39:58 -05:00
fadvise.c check ADVICE of fadvise64_64 even if get_xip_page is given 2008-02-05 09:44:19 -08:00
filemap.c kill do_generic_mapping_read 2008-02-08 09:22:39 -08:00
filemap_xip.c Use pgoff_t instead of unsigned long 2008-02-08 09:22:32 -08:00
fremap.c sys_remap_file_pages: fix ->vm_file accounting 2008-02-05 09:44:07 -08:00
highmem.c mm: remove fastcall from mm/ 2008-02-05 09:44:18 -08:00
hugetlb.c hugetlb: add locking for overcommit sysctl 2008-02-08 09:22:23 -08:00
internal.h set_page_refcounted() VM_BUG_ON fix 2008-02-05 09:44:19 -08:00
madvise.c speed up madvise_need_mmap_write() usage 2007-07-16 09:05:36 -07:00
memcontrol.c Memory controller remove control_type feature 2008-02-07 08:42:22 -08:00
memory.c CONFIG_HIGHPTE vs. sub-page page tables. 2008-02-08 09:22:42 -08:00
memory_hotplug.c Page allocator: clean up pcp draining functions 2008-02-05 09:44:17 -08:00
mempolicy.c Migration: find correct vma in new_vma_page() 2007-11-14 18:45:38 -08:00
mempool.c spelling fixes: mm/ 2007-10-20 01:27:18 +02:00
migrate.c bugfix for memory cgroup controller: migration under memory controller fix 2008-02-07 08:42:19 -08:00
mincore.c [PATCH] mincore: vma crossing fix 2007-02-15 09:57:03 -08:00
mlock.c do not limit locked memory when RLIMIT_MEMLOCK is RLIM_INFINITY 2007-07-16 09:05:37 -07:00
mmap.c brk: check the lower bound properly 2008-02-06 22:39:44 +01:00
mmzone.c [PATCH] remove EXPORT_UNUSED_SYMBOL'ed symbols 2006-12-07 08:39:44 -08:00
mprotect.c fix mprotect vma_wants_writenotify prot 2007-10-23 08:32:06 -07:00
mremap.c sparse pointer use of zero as null 2007-10-18 14:37:31 -07:00
msync.c Detach sched.h from mm.h 2007-05-21 09:18:19 -07:00
nommu.c nommu: add new vmalloc_user() and remap_vmalloc_range() interfaces. 2008-02-05 09:44:21 -08:00
oom_kill.c oom: add sysctl to enable task memory dump 2008-02-07 08:42:19 -08:00
page-writeback.c writeback: speed up writeback of big dirty files 2008-02-05 09:44:19 -08:00
page_alloc.c misc: removal of final callers using fastcall 2008-02-08 09:22:31 -08:00
page_io.c mm: fix PageUptodate data race 2008-02-05 09:44:19 -08:00
page_isolation.c memory hotremove: unset migrate type "ISOLATE" after removal 2007-11-14 18:45:38 -08:00
pagewalk.c maps4: introduce a generic page walker 2008-02-05 09:44:16 -08:00
pdflush.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
prio_tree.c spelling fixes: mm/ 2007-10-20 01:27:18 +02:00
quicklist.c quicklists: Only consider memory that can be used with GFP_KERNEL 2008-01-14 08:52:22 -08:00
readahead.c mm: bdi init hooks 2007-10-17 08:42:45 -07:00
rmap.c Memory controller: make page_referenced() cgroup aware 2008-02-07 08:42:19 -08:00
shmem.c mount-options-fix-tmpfs-fix 2008-02-08 09:22:41 -08:00
shmem_acl.c [PATCH] Fix typos in mm/shmem_acl.c 2006-10-11 11:14:23 -07:00
slab.c cpu-hotplug: replace per-subsystem mutexes with get_online_cpus() 2008-01-25 21:08:02 +01:00
slob.c slob: reduce external fragmentation by using three free lists 2008-02-05 09:44:19 -08:00
slub.c SLUB: fix checkpatch warnings 2008-02-07 17:52:39 -08:00
sparse-vmemmap.c memory hotplug fix: fix section mismatch in vmammap_allock_block() 2007-11-29 09:24:54 -08:00
sparse.c mm: fix section mismatch warning in sparse.c 2008-02-05 09:44:19 -08:00
swap.c Memory controller: add per cgroup LRU and reclaim 2008-02-07 08:42:18 -08:00
swap_state.c memcgroup: revert swap_state mods 2008-02-07 08:42:20 -08:00
swapfile.c memcgroup: reinstate swapoff mod 2008-02-07 08:42:19 -08:00
thrash.c Bug in mm/thrash.c function grab_swap_token() 2007-05-11 08:29:32 -07:00
tiny-shmem.c Remove unused code from mm/tiny-shmem.c 2008-02-05 09:44:17 -08:00
truncate.c page migraton: handle orphaned pages 2008-02-05 09:44:19 -08:00
util.c fix mm/util.c:krealloc() 2007-11-14 18:45:41 -08:00
vmalloc.c CONFIG_HIGHPTE vs. sub-page page tables. 2008-02-08 09:22:42 -08:00
vmscan.c per-zone and reclaim enhancements for memory controller: modifies vmscan.c for isolate globa/cgroup lru activity 2008-02-07 08:42:22 -08:00
vmstat.c vmstat: remove prefetch 2008-02-05 09:44:18 -08:00