linux/arch
Hugh Dickins 872fec16d9 [PATCH] mm: init_mm without ptlock
First step in pushing down the page_table_lock.  init_mm.page_table_lock has
been used throughout the architectures (usually for ioremap): not to serialize
kernel address space allocation (that's usually vmlist_lock), but because
pud_alloc,pmd_alloc,pte_alloc_kernel expect caller holds it.

Reverse that: don't lock or unlock init_mm.page_table_lock in any of the
architectures; instead rely on pud_alloc,pmd_alloc,pte_alloc_kernel to take
and drop it when allocating a new one, to check lest a racing task already
did.  Similarly no page_table_lock in vmalloc's map_vm_area.

Some temporary ugliness in __pud_alloc and __pmd_alloc: since they also handle
user mms, which are converted only by a later patch, for now they have to lock
differently according to whether or not it's init_mm.

If sources get muddled, there's a danger that an arch source taking
init_mm.page_table_lock will be mixed with common source also taking it (or
neither take it).  So break the rules and make another change, which should
break the build for such a mismatch: remove the redundant mm arg from
pte_alloc_kernel (ppc64 scrapped its distinct ioremap_mm in 2.6.13).

Exceptions: arm26 used pte_alloc_kernel on user mm, now pte_alloc_map; ia64
used pte_alloc_map on init_mm, now pte_alloc_kernel; parisc had bad args to
pmd_alloc and pte_alloc_kernel in unused USE_HPPA_IOREMAP code; ppc64
map_io_page forgot to unlock on failure; ppc mmu_mapin_ram and ppc64 im_free
took page_table_lock for no good reason.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:40 -07:00
..
alpha [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
arm [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
arm26 [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
cris [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
frv [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
h8300 kbuild: h8300,m68knommu,sh,sh64 use generic asm-offsets.h support 2005-09-09 20:28:49 +02:00
i386 [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
ia64 [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
m32r [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
m68k [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
m68knommu [PATCH] m68knommu: startup code for the Drangen Engine 68328 based board 2005-09-12 20:04:15 -07:00
mips [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
parisc [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
ppc [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
ppc64 [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
s390 [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
sh [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
sh64 [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
sparc [PATCH] core remove PageReserved 2005-10-29 21:40:39 -07:00
sparc64 [PATCH] core remove PageReserved 2005-10-29 21:40:39 -07:00
um [PATCH] gfp_t: remaining bits of arch/* 2005-10-28 08:16:51 -07:00
v850 [PATCH] V850: C99 initializers for hw_interrupt_type structures 2005-09-10 10:06:27 -07:00
x86_64 [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
xtensa [PATCH] gfp_t: dma-mapping (xtensa) 2005-10-28 08:16:49 -07:00