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f6b3ec238d
linux/include/asm-i386
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Badari Pulavarty f6b3ec238d [PATCH] madvise(MADV_REMOVE): remove pages from tmpfs shm backing store 
Here is the patch to implement madvise(MADV_REMOVE) - which frees up a
given range of pages & its associated backing store.  Current
implementation supports only shmfs/tmpfs and other filesystems return
-ENOSYS.

"Some app allocates large tmpfs files, then when some task quits and some
client disconnect, some memory can be released.  However the only way to
release tmpfs-swap is to MADV_REMOVE". - Andrea Arcangeli

Databases want to use this feature to drop a section of their bufferpool
(shared memory segments) - without writing back to disk/swap space.

This feature is also useful for supporting hot-plug memory on UML.

Concerns raised by Andrew Morton:

- "We have no plan for holepunching!  If we _do_ have such a plan (or
  might in the future) then what would the API look like?  I think
  sys_holepunch(fd, start, len), so we should start out with that."

- Using madvise is very weird, because people will ask "why do I need to
  mmap my file before I can stick a hole in it?"

- None of the other madvise operations call into the filesystem in this
  manner.  A broad question is: is this capability an MM operation or a
  filesytem operation?  truncate, for example, is a filesystem operation
  which sometimes has MM side-effects.  madvise is an mm operation and with
  this patch, it gains FS side-effects, only they're really, really
  significant ones."

Comments:

- Andrea suggested the fs operation too but then it's more efficient to
  have it as a mm operation with fs side effects, because they don't
  immediatly know fd and physical offset of the range.  It's possible to
  fixup in userland and to use the fs operation but it's more expensive,
  the vmas are already in the kernel and we can use them.

Short term plan &  Future Direction:

- We seem to need this interface only for shmfs/tmpfs files in the short
  term.  We have to add hooks into the filesystem for correctness and
  completeness.  This is what this patch does.

- In the future, plan is to support both fs and mmap apis also.  This
  also involves (other) filesystem specific functions to be implemented.

- Current patch doesn't support VM_NONLINEAR - which can be addressed in
  the future.

Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Andrea Arcangeli <andrea@suse.de>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:22 -08:00
..
mach-bigsmp [PATCH] Do not enforce unique IO_APIC_ID check for xAPIC systems (i386) 2005-06-23 09:45:09 -07:00
mach-default [PATCH] x86_64: Reduce number of retries for reset through keyboard controller 2005-11-14 19:55:16 -08:00
mach-es7000 [PATCH] ES7000 platform update 2005-10-30 17:37:12 -08:00
mach-generic [PATCH] x86: sutomatically enable bigsmp when we have more than 8 CPUs 2005-09-05 00:06:10 -07:00
mach-numaq [PATCH] Do not enforce unique IO_APIC_ID check for xAPIC systems (i386) 2005-06-23 09:45:09 -07:00
mach-summit [PATCH] USB: Always do usb-handoff 2005-10-28 16:47:49 -07:00
mach-visws Revert "i386: move apic init in init_IRQs" 2005-10-31 19:16:17 -08:00
mach-voyager Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
8253pit.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
a.out.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
acpi.h [ACPI] delete CONFIG_ACPI_PCI 2005-08-25 12:40:44 -04:00
agp.h [PATCH] i386: inline asm cleanup 2005-09-05 00:06:11 -07:00
apic.h Revert "i386: move apic init in init_IRQs" 2005-10-31 19:16:17 -08:00
apicdef.h [PATCH] x86: sutomatically enable bigsmp when we have more than 8 CPUs 2005-09-05 00:06:10 -07:00
arch_hooks.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
atomic.h [PATCH] atomic: inc_not_zero 2005-11-13 18:14:16 -08:00
auxvec.h [PATCH] auxiliary vector cleanups 2005-09-07 16:57:21 -07:00
bitops.h [FLS64]: generic version 2006-01-03 13:11:06 -08:00
boot.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
bug.h [PATCH] remove all kernel BUGs 2005-05-01 08:59:01 -07:00
bugs.h [PATCH] i386: inline asm cleanup 2005-09-05 00:06:11 -07:00
byteorder.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cache.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cacheflush.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
checksum.h [NET]: Fix ipl=>ihl typo in ip_fast_csum 2005-08-29 16:02:48 -07:00
cpu.h [PATCH] i386 CPU hotplug 2005-06-25 16:24:29 -07:00
cpufeature.h [PATCH] CPUID bug and inconsistency fix 2005-05-01 08:58:49 -07:00
cputime.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
current.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
debugreg.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
delay.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
desc.h [PATCH] x86: add an accessor function for getting the per-CPU gdt 2005-10-30 17:37:12 -08:00
div64.h [PATCH] include/asm-i386/: "extern inline" -> "static inline" 2005-09-10 10:06:34 -07:00
dma-mapping.h [PATCH] gfp flags annotations - part 1 2005-10-08 15:00:57 -07:00
dma.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
e820.h [PATCH] Increase number of e820 entries hard limit from 32 to 128 2005-05-01 08:58:51 -07:00
elf.h [PATCH] fix remaining missing includes 2005-11-07 07:53:41 -08:00
emergency-restart.h [PATCH] i386: Implement machine_emergency_reboot 2005-07-26 14:35:42 -07:00
errno.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
fcntl.h [PATCH] Clean up struct flock64 definitions 2005-09-07 16:57:38 -07:00
fixmap.h [ACPI] delete CONFIG_ACPI_BOOT 2005-08-24 12:08:54 -04:00
floppy.h [PATCH] make some things static 2005-05-05 16:36:47 -07:00
futex.h [PATCH] uml: adapt asm/futex.h to our arch 2005-09-21 16:16:29 -07:00
genapic.h [PATCH] Do not enforce unique IO_APIC_ID check for xAPIC systems (i386) 2005-06-23 09:45:09 -07:00
hardirq.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
highmem.h [PATCH] kdump: Routines for copying dump pages 2005-06-25 16:24:53 -07:00
hpet.h [PATCH] i386: fix hpet for systems that don't support legacy replacement 2005-05-01 08:58:50 -07:00
hw_irq.h Revert "i386: move apic init in init_IRQs" 2005-10-31 19:16:17 -08:00
i387.h x86: use alternative instructions for fnsave/fxsave too 2005-07-22 18:19:20 -04:00
i8253.h [PATCH] x86: i8253/i8259A lock cleanup 2005-06-30 08:45:10 -07:00
i8259.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ide.h [PATCH] ide: explain the PCI bus test we do in <asm-i386/ide.h> 2005-11-10 00:10:37 +01:00
io_apic.h [ACPI] delete CONFIG_ACPI_BOOT 2005-08-24 12:08:54 -04:00
io.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ioctl.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ioctls.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ipc.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ipcbuf.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
irq.h [PATCH] cpu state clean after hot remove 2005-06-25 16:24:30 -07:00
ist.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
kdebug.h [PATCH] x86 NMI: better support for debuggers 2005-09-05 00:06:13 -07:00
kexec.h [PATCH] Kdump: Export crash notes section address through sysfs 2005-06-25 16:24:51 -07:00
kmap_types.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
kprobes.h [PATCH] Kprobes: Track kprobe on a per_cpu basis - i386 changes 2005-11-07 07:53:45 -08:00
ldt.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
linkage.h [PATCH] i386: fix prevent_tail_call 2005-05-26 16:16:16 -07:00
local.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
math_emu.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mc146818rtc.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mca_dma.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mca.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mman.h [PATCH] madvise(MADV_REMOVE): remove pages from tmpfs shm backing store 2006-01-06 08:33:22 -08:00
mmu_context.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mmu.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mmx.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mmzone.h [PATCH] memory hotplug prep: kill local_mapnr 2005-10-29 21:40:44 -07:00
module.h [PATCH] x86: geode support fixes 2005-05-05 16:36:49 -07:00
mpspec_def.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mpspec.h Merge linux-2.6 with linux-acpi-2.6 2005-09-08 01:45:47 -04:00
msgbuf.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
msi.h [PATCH] PCI: Change MSI to use physical delivery mode always 2005-11-10 16:09:18 -08:00
msr.h [PATCH] x86: more asm cleanups 2005-09-05 00:06:12 -07:00
mtrr.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
namei.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
nmi.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
node.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
numa.h [PATCH] x86-64: Use ACPI PXM to parse PCI<->node assignments 2005-09-12 10:49:57 -07:00
numaq.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
numnodes.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
page.h [PATCH] remove hugetlb_clean_stale_pgtable() and fix huge_pte_alloc() 2005-09-05 00:05:46 -07:00
param.h [PATCH] Avoid namespace pollution in <asm/param.h> 2006-01-02 08:38:38 -08:00
parport.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
pci-direct.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
pci.h Revert PCIBIOS_MIN_IO changes for 2.6.13 2005-08-14 18:21:30 -07:00
percpu.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
pgalloc.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
pgtable-2level-defs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
pgtable-2level.h [PATCH] i386: little pgtable.h consolidation vs 2/3level 2005-10-30 17:37:12 -08:00
pgtable-3level-defs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
pgtable-3level.h [PATCH] i386: little pgtable.h consolidation vs 2/3level 2005-10-30 17:37:12 -08:00
pgtable.h [PATCH] fix remaining missing includes 2005-11-07 07:53:41 -08:00
poll.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
posix_types.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
processor.h Merge x86-64 update from Andi 2005-11-14 19:56:02 -08:00
ptrace.h [PATCH] x86: privilege cleanup 2005-09-05 00:06:12 -07:00
resource.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
rtc.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
rwlock.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
rwsem.h [PATCH] add sem_is_read/write_locked() 2005-10-29 21:40:35 -07:00
scatterlist.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
seccomp.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sections.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
segment.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
semaphore.h [PATCH] semaphore: Remove __MUTEX_INITIALIZER() 2005-10-30 17:37:27 -08:00
sembuf.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
serial.h [PATCH] Serial: Split 8250 port table (part 2) 2005-06-29 18:45:19 +01:00
setup.h [PATCH] x86: fix EFI memory map parsing 2005-09-05 00:06:09 -07:00
shmbuf.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
shmparam.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sigcontext.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
siginfo.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
signal.h x86: Fix silly typo in recent <asm/signal.h> fixes 2005-11-17 10:04:31 -08:00
smp.h [PATCH] PCI: Change MSI to use physical delivery mode always 2005-11-10 16:09:18 -08:00
socket.h [NET]: Introduce SO_{SND,RCV}BUFFORCE socket options 2005-08-29 15:31:35 -07:00
sockios.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sparsemem.h [PATCH] sparsemem memory model for i386 2005-06-23 09:45:05 -07:00
spinlock_types.h [PATCH] spinlock consolidation 2005-09-10 10:06:21 -07:00
spinlock.h [PATCH] spinlock consolidation 2005-09-10 10:06:21 -07:00
srat.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
stat.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
statfs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
string.h Add "memory" clobbers to the x86 inline asm of strncmp and friends 2005-06-24 10:39:17 -07:00
suspend.h [PATCH] i386: Use loaddebug macro consistently 2005-04-16 15:24:46 -07:00
system.h [PATCH] i386: generic cmpxchg 2005-11-13 18:14:15 -08:00
termbits.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
termios.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
thread_info.h kbuild: full dependency check on asm-offsets.h 2005-09-09 19:28:28 +02:00
timer.h [PATCH] add suspend/resume for timer 2005-09-05 00:06:18 -07:00
timex.h [PATCH] x86: cpu_khz type fix 2005-06-23 09:45:11 -07:00
tlb.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
tlbflush.h [PATCH] seccomp: tsc disable 2005-06-27 15:11:44 -07:00
topology.h [PATCH] x86-64: Use ACPI PXM to parse PCI<->node assignments 2005-09-12 10:49:57 -07:00
types.h [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
uaccess.h [PATCH] remove verify_area(): remove verify_area() from various uaccess.h headers 2005-09-07 16:57:35 -07:00
ucontext.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
unaligned.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
unistd.h [PATCH] unify sys_ptrace prototype 2005-10-30 17:37:20 -08:00
user.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
vga.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
vic.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
vm86.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
voyager.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
xor.h [PATCH] i386: inline asm cleanup 2005-09-05 00:06:11 -07:00