kernel_optimize_test/include/asm-parisc
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>
2008-04-28 08:58:23 -07:00
..
a.out.h aout: move STACK_TOP[_MAX] to asm/processor.h 2008-02-08 09:22:29 -08:00
agp.h x86: remove flush_agp_mappings() 2008-01-30 13:34:07 +01:00
asmregs.h
assembly.h [PARISC] convert to use CONFIG_64BIT instead of __LP64__ 2007-02-17 01:17:13 -05:00
atomic.h Add cmpxchg_local to parisc 2008-02-07 08:42:32 -08:00
auxvec.h [PATCH] auxiliary vector cleanups 2005-09-07 16:57:21 -07:00
bitops.h generic: implement __fls on all 64-bit archs 2008-04-26 19:21:16 +02:00
bug.h Fix WARN_ON() on bitfield ops for all other archs 2007-08-01 20:45:38 -07:00
bugs.h
byteorder.h
cache.h [PARISC] Clean up the cache and tlb headers 2007-02-17 00:41:30 -05:00
cacheflush.h [PARISC] Add prototypes for flush_user_dcache_range and flush_user_icache_range 2007-02-17 00:43:51 -05:00
checksum.h [NET]: PARISC checksum annotations and cleanups. 2006-12-02 21:23:10 -08:00
compat_rt_sigframe.h
compat_signal.h
compat_ucontext.h [PARISC] Arch-specific compat signals 2006-01-22 20:57:42 -05:00
compat.h asm-*/compat.h: fix typo in comment 2008-02-03 16:32:51 +02:00
cputime.h
current.h
delay.h
device.h Driver core: add dev_archdata to struct device 2006-12-01 14:52:01 -08:00
div64.h
dma-mapping.h [PARISC] Fix ccio_request_resource when CONFIG_IOMMU_CCIO is not defined 2006-12-08 00:33:59 -05:00
dma.h Fix misc .c/.h comment typos 2006-11-30 05:24:39 +01:00
eisa_bus.h
eisa_eeprom.h
elf.h [PARISC] clean up include/asm-parisc/elf.h 2008-03-15 19:12:10 -07:00
emergency-restart.h [PATCH] Add emergency_restart() 2005-07-26 14:35:41 -07:00
errno.h [PARISC] Add ECANCELED to errno.h 2005-10-21 22:53:43 -04:00
fb.h fbdev: detect primary display device 2007-07-17 10:23:11 -07:00
fcntl.h Introduce O_CLOEXEC 2007-07-16 09:05:45 -07:00
fixmap.h [PARISC] move VMALLOC_* definitions to fixmap.h 2008-03-15 19:11:49 -07:00
floppy.h cleanup floppy.h 2007-10-17 08:42:55 -07:00
futex.h [PARISC] futex: special case cmpxchg NULL in kernel space 2008-03-15 19:12:17 -07:00
grfioctl.h [PARISC] Use kzalloc and other janitor-style cleanups 2006-01-22 20:26:31 -05:00
hardirq.h
hardware.h [PARISC] fix section mismatches in arch/parisc/kernel 2007-05-27 13:36:27 -04:00
hw_irq.h [PATCH] genirq: add ->retrigger() irq op to consolidate hw_irq_resend() 2006-06-29 10:26:23 -07:00
ide.h ide: remove ide_default_io_ctl() macro 2008-04-18 00:46:34 +02:00
io.h [PARISC] parisc: "extern inline" -> "static inline" 2007-10-18 00:58:41 -07:00
ioctl.h
ioctls.h
ipcbuf.h
irq_regs.h Build fixes for struct pt_regs removal 2006-10-06 20:47:23 -06:00
irq.h [PARISC] Allow nested interrupts 2006-10-04 06:48:57 -06:00
Kbuild [PARISC] Export pdc.h for palo 2007-10-18 00:58:29 -07:00
kdebug.h move die notifier handling to common code 2007-05-08 11:15:04 -07:00
kmap_types.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
kvm.h kvm: provide kvm.h for all architecture: fixes headers_install 2008-04-02 15:28:18 -07:00
led.h [PARISC] Convert soft power switch driver to kthread 2007-02-17 01:03:43 -05:00
linkage.h include/asm-parisc/: Spelling fixes 2008-02-03 17:00:11 +02:00
local.h local_t: parisc cleanup 2007-05-08 11:15:20 -07:00
machdep.h
mc146818rtc.h
mckinley.h [PARISC] Add asm-parisc/mckinley.h bus header 2006-10-04 06:45:48 -06:00
mman.h [PATCH] Remove final references to deprecated "MAP_ANON" page protection flag 2007-02-11 10:51:17 -08:00
mmu_context.h Detach sched.h from mm.h 2007-05-21 09:18:19 -07:00
mmu.h
mmzone.h [PARISC] convert to use CONFIG_64BIT instead of __LP64__ 2007-02-17 01:17:13 -05:00
module.h [PARISC] convert to use CONFIG_64BIT instead of __LP64__ 2007-02-17 01:17:13 -05:00
msgbuf.h [PARISC] convert to use CONFIG_64BIT instead of __LP64__ 2007-02-17 01:17:13 -05:00
mutex.h [PATCH] mutex subsystem, add default include/asm-*/mutex.h files 2006-01-09 15:59:19 -08:00
namei.h
page.h CONFIG_HIGHPTE vs. sub-page page tables. 2008-02-08 09:22:42 -08:00
param.h [PARISC] Use CONFIG_HZ to determine interval timer rate (aka clock ticks) 2006-10-04 06:47:46 -06:00
parisc-device.h [PARISC] convert to use CONFIG_64BIT instead of __LP64__ 2007-02-17 01:17:13 -05:00
parport.h
pci.h [PARISC] parisc: "extern inline" -> "static inline" 2007-10-18 00:58:41 -07:00
pdc_chassis.h [PARISC] Clarify pdc_stable license terms 2006-03-30 17:48:41 +00:00
pdc.h [PARISC] pdc_console: fix bizarre panic on boot 2008-03-15 19:12:03 -07:00
pdcpat.h [PARISC] Remove duplicate PDC_PAT_CELL defines 2006-12-08 00:34:47 -05:00
percpu.h
perf.h
pgalloc.h [PARISC] unbreak pgalloc.h 2008-03-15 19:11:52 -07:00
pgtable.h mm: introduce pte_special pte bit 2008-04-28 08:58:23 -07:00
poll.h Consolidate asm/poll.h 2007-05-11 08:29:34 -07:00
posix_types.h asm-*/posix_types.h: scrub __GLIBC__ 2008-02-08 09:22:34 -08:00
prefetch.h [PARISC] parisc: "extern inline" -> "static inline" 2007-10-18 00:58:41 -07:00
processor.h aout: move STACK_TOP[_MAX] to asm/processor.h 2008-02-08 09:22:29 -08:00
psw.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
ptrace.h [PARISC] Take into account nullified insn and lock functions for profiling 2005-10-21 22:42:18 -04:00
real.h
resource.h
ropes.h Fix misc .c/.h comment typos 2006-11-30 05:24:39 +01:00
rt_sigframe.h [PARISC] Arch-specific compat signals 2006-01-22 20:57:42 -05:00
rtc.h [PARISC] fix uninitialized variable warning in asm/rtc.h 2007-10-20 13:23:00 -07:00
runway.h
scatterlist.h parisc: fix sg_page() fallout 2007-10-23 09:49:31 +02:00
sections.h
segment.h
semaphore.h Generic semaphore implementation 2008-04-17 10:42:34 -04:00
sembuf.h [PARISC] convert to use CONFIG_64BIT instead of __LP64__ 2007-02-17 01:17:13 -05:00
serial.h [PARISC] Clean up asm-parisc/serial.h 2006-10-04 06:47:03 -06:00
setup.h
shmbuf.h [PARISC] convert to use CONFIG_64BIT instead of __LP64__ 2007-02-17 01:17:13 -05:00
shmparam.h
sigcontext.h
siginfo.h
signal.h [PARISC] convert to use CONFIG_64BIT instead of __LP64__ 2007-02-17 01:17:13 -05:00
smp.h [PARISC] kill ENTRY_SYS_CPUS 2007-02-17 01:11:41 -05:00
socket.h [NET]: Introducing socket mark socket option. 2008-01-31 19:27:19 -08:00
sockios.h [NET]: Introduce SIOCGSTAMPNS ioctl to get timestamps with nanosec resolution 2007-04-25 22:24:04 -07:00
spinlock_types.h [PARISC] "Fix" circular includes 2007-02-17 00:43:10 -05:00
spinlock.h [PARISC] Enable interrupts while spinning 2006-10-04 06:48:17 -06:00
stat.h
statfs.h [PATCH] use __u64 rather than u64 in parisc statfs structs 2007-02-08 18:56:57 -05:00
string.h
superio.h
system.h [PATCH] sched: sched_cacheflush is now unused 2007-07-19 21:28:35 +02:00
termbits.h lots-of-architectures: enable arbitary speed tty support 2007-07-10 17:51:13 -07:00
termios.h [PATCH] consolidate line discipline number definitions 2007-02-11 10:51:26 -08:00
thread_info.h remove unused TIF_NOTIFY_RESUME flag 2007-07-31 15:39:38 -07:00
timex.h
tlb.h add mm argument to pte/pmd/pud/pgd_free 2008-02-05 09:44:18 -08:00
tlbflush.h remove unused flush_tlb_pgtables 2007-10-19 11:53:34 -07:00
topology.h
traps.h
types.h remove strict ansi check from __u64 in asm/types.h 2007-10-17 08:42:53 -07:00
uaccess.h [PARISC] add ASM_EXCEPTIONTABLE_ENTRY() macro 2007-02-17 01:16:26 -05:00
ucontext.h
unaligned.h
unistd.h [PARISC] bump __NR_syscalls 2008-03-15 19:11:54 -07:00
unwind.h
user.h
vga.h vga.h: Fix prepocessor warning 2008-02-03 15:59:02 +02:00
xor.h