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Nick Piggin 7e675137a8 mm: introduce pte_special pte bit ... s390 for one, cannot implement VM_MIXEDMAP with pfn_valid, due to their memory model (which is more dynamic than most). Instead, they had proposed to implement it with an additional path through vm_normal_page(), using a bit in the pte to determine whether or not the page should be refcounted: vm_normal_page() { ... if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { if (vma->vm_flags & VM_MIXEDMAP) { #ifdef s390 if (!mixedmap_refcount_pte(pte)) return NULL; #else if (!pfn_valid(pfn)) return NULL; #endif goto out; } ... } This is fine, however if we are allowed to use a bit in the pte to determine refcountedness, we can use that to _completely_ replace all the vma based schemes. So instead of adding more cases to the already complex vma-based scheme, we can have a clearly seperate and simple pte-based scheme (and get slightly better code generation in the process): vm_normal_page() { #ifdef s390 if (!mixedmap_refcount_pte(pte)) return NULL; return pte_page(pte); #else ... #endif } And finally, we may rather make this concept usable by any architecture rather than making it s390 only, so implement a new type of pte state for this. Unfortunately the old vma based code must stay, because some architectures may not be able to spare pte bits. This makes vm_normal_page a little bit more ugly than we would like, but the 2 cases are clearly seperate. So introduce a pte_special pte state, and use it in mm/memory.c. It is currently a noop for all architectures, so this doesn't actually result in any compiled code changes to mm/memory.o. BTW: I haven't put vm_normal_page() into arch code as-per an earlier suggestion. The reason is that, regardless of where vm_normal_page is actually implemented, the *abstraction* is still exactly the same. Also, while it depends on whether the architecture has pte_special or not, that is the only two possible cases, and it really isn't an arch specific function -- the role of the arch code should be to provide primitive functions and accessors with which to build the core code; pte_special does that. We do not want architectures to know or care about vm_normal_page itself, and we definitely don't want them being able to invent something new there out of sight of mm/ code. If we made vm_normal_page an arch function, then we have to make vm_insert_mixed (next patch) an arch function too. So I don't think moving it to arch code fundamentally improves any abstractions, while it does practically make the code more difficult to follow, for both mm and arch developers, and easier to misuse. [akpm@linux-foundation.org: build fix] Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: Carsten Otte <cotte@de.ibm.com> Cc: Jared Hulbert <jaredeh@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		17 years ago
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Kbuild	Unexport asm/page.h	17 years ago
atomic.h	Fix FRV cmpxchg_local	17 years ago
auxvec.h	…
ax88796.h	…
bitops.h	Fix FRV cmpxchg_local	17 years ago
bug.h	Don't include linux/config.h from anywhere else in include/	19 years ago
bugs.h	…
busctl-regs.h	…
byteorder.h	…
cache.h	Don't include linux/config.h from anywhere else in include/	19 years ago
cacheflush.h	include/asm-frv/: Spelling fixes	17 years ago
checksum.h	[NET]: FRV checksum annotations.	18 years ago
cpu-irqs.h	[PATCH] FRV: Use the generic IRQ stuff	19 years ago
cpumask.h	…
cputime.h	…
current.h	…
delay.h	…
device.h	Driver core: add dev_archdata to struct device	18 years ago
div64.h	…
dm9000.h	…
dma-mapping.h	FRV: move DMA macros to scatterlist.h for consistency.	17 years ago
dma.h	IRQ: Maintain regs pointer globally rather than passing to IRQ handlers	19 years ago
elf.h	Cleanup asm/{elf,page,user}.h: #ifdef __KERNEL__ is no longer needed	17 years ago
emergency-restart.h	…
errno.h	…
fb.h	fbdev: detect primary display device	18 years ago
fcntl.h	…
fpu.h	Don't include linux/config.h from anywhere else in include/	19 years ago
futex.h	[PATCH] lightweight robust futexes updates	19 years ago
gdb-stub.h	[PATCH] FRV: Introduce asm-offsets for FRV arch	19 years ago
gpio-regs.h	…
hardirq.h	[PATCH] FRV: Use the generic IRQ stuff	19 years ago
highmem.h	move frv docs one level up	17 years ago
hw_irq.h	…
ide.h	ide: remove stale ide.h "configuration options"	17 years ago
init.h	…
io.h	[PATCH] Consolidate check_signature	19 years ago
ioctl.h	[PATCH] Generic ioctl.h	19 years ago
ioctls.h	…
ipcbuf.h	…
irc-regs.h	…
irq.h	frv: Remove bogus NO_IRQ = -1 define	17 years ago
irq_regs.h	IRQ: Maintain regs pointer globally rather than passing to IRQ handlers	19 years ago
kdebug.h	move die notifier handling to common code	18 years ago
kmap_types.h	…
kvm.h	kvm: provide kvm.h for all architecture: fixes headers_install	17 years ago
linkage.h	…
local.h	…
math-emu.h	…
mb-regs.h	[PATCH] frv: basic __iomem annotations	19 years ago
mb86943a.h	FRV: Enable the MB86943 PCI arbiter correctly	18 years ago
mb93091-fpga-irqs.h	[PATCH] FRV: Use the generic IRQ stuff	19 years ago
mb93093-fpga-irqs.h	[PATCH] FRV: Use the generic IRQ stuff	19 years ago
mb93493-irqs.h	[PATCH] FRV: Use the generic IRQ stuff	19 years ago
mb93493-regs.h	[PATCH] FRV: Use the generic IRQ stuff	19 years ago
mc146818rtc.h	[PATCH] frv: miscellaneous changes	19 years ago
mem-layout.h	FRV: Move STACK_TOP_MAX up [try #2]	17 years ago
mman.h	[PATCH] add asm-generic/mman.h	19 years ago
mmu.h	…
mmu_context.h	[PATCH] x86: PARAVIRT: add hooks to intercept mm creation and destruction	18 years ago
module.h	[PATCH] frv: add module support stubs	19 years ago
msgbuf.h	…
mutex.h	[PATCH] mutex subsystem, add default include/asm-*/mutex.h files	19 years ago
namei.h	fix file specification in comments	19 years ago
page.h	CONFIG_HIGHPTE vs. sub-page page tables.	17 years ago
param.h	avoid overflows in kernel/time.c	17 years ago
pci.h	PCI: remove pci_dac_dma_... APIs	18 years ago
percpu.h	…
pgalloc.h	CONFIG_HIGHPTE vs. sub-page page tables.	17 years ago
pgtable.h	mm: introduce pte_special pte bit	17 years ago
poll.h	Consolidate asm/poll.h	18 years ago
posix_types.h	asm-*/posix_types.h: scrub __GLIBC__	17 years ago
processor.h	[PATCH] Make cpu_relax() imply barrier() on all arches	19 years ago
ptrace.h	[PATCH] fix frv headers_check	18 years ago
registers.h	[PATCH] FRV: Introduce asm-offsets for FRV arch	19 years ago
resource.h	…
scatterlist.h	FRV: move DMA macros to scatterlist.h for consistency.	17 years ago
sections.h	…
segment.h	Don't include linux/config.h from anywhere else in include/	19 years ago
semaphore.h	Generic semaphore implementation	17 years ago
sembuf.h	…
serial-regs.h	…
serial.h	Don't include linux/config.h from anywhere else in include/	19 years ago
setup.h	[PATCH] cleanup asm/setup.h userspace visibility	18 years ago
shmbuf.h	…
shmparam.h	…
sigcontext.h	…
siginfo.h	…
signal.h	[PATCH] irq-flags: FRV: Use the new IRQF_ constants	19 years ago
smp.h	Don't include linux/config.h from anywhere else in include/	19 years ago
socket.h	[NET]: Introducing socket mark socket option.	17 years ago
sockios.h	[NET]: Introduce SIOCGSTAMPNS ioctl to get timestamps with nanosec resolution	18 years ago
spinlock.h	…
spr-regs.h	FRV: Add support for emulation of userspace atomic ops [try #2]	17 years ago
stat.h	…
statfs.h	…
string.h	…
suspend.h	…
system.h	frv: remove HARD_RESET_NOW()	17 years ago
termbits.h	lots-of-architectures: enable arbitary speed tty support	18 years ago
termios.h	[PATCH] consolidate line discipline number definitions	18 years ago
thread_info.h	include/asm-frv/thread_info.h: kmalloc + memset conversion to kzalloc	18 years ago
timer-regs.h	…
timex.h	[PATCH] ntp: cleanup defines and comments	19 years ago
tlb.h	FRV: Replace pgd management via slabs through quicklists	18 years ago
tlbflush.h	remove unused flush_tlb_pgtables	18 years ago
topology.h	asm-generic: add node_to_cpumask_ptr macro	17 years ago
types.h	remove strict ansi check from __u64 in asm/types.h	18 years ago
uaccess.h	frv: missing __clear_user()	18 years ago
ucontext.h	…
unaligned.h	Don't include linux/config.h from anywhere else in include/	19 years ago
unistd.h	FRV: Change the timerfd syscalls to be the same as i386	17 years ago
user.h	…
vga.h	[PATCH] frv: miscellaneous changes	19 years ago
virtconvert.h	Don't include linux/config.h from anywhere else in include/	19 years ago
xor.h	[PATCH] frv: miscellaneous changes	19 years ago