There are some places to be able to use printk_once instead of hard coding.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
put_cpu_no_resched() is an optimization of put_cpu() which unfortunately
can cause high latencies.
The nfs iostats code uses put_cpu_no_resched() in a code sequence where a
reschedule request caused by an interrupt between the get_cpu() and the
put_cpu_no_resched() can delay the reschedule for at least HZ.
The other users of put_cpu_no_resched() optimize correctly in interrupt
code, but there is no real harm in using the put_cpu() function which is
an alias for preempt_enable(). The extra check of the preemmpt count is
not as critical as the potential source of missing a reschedule.
Debugged in the preempt-rt tree and verified in mainline.
Impact: remove a high latency source
[akpm@linux-foundation.org: build fix]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
`ELF_CORE_COPY_REGS(x, y)' will make expansions like:
`(y)[0] = (x)->x.gp[0]' but correct is `(y)[0] = (x)->regs.gp[0]'
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: WANG Cong <amwang@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When compiling uml on x86_64:
MODPOST vmlinux.o
WARNING: vmlinux.o (.__syscall_stub.2): unexpected non-allocatable section.
Did you forget to use "ax"/"aw" in a .S file?
Note that for example <linux/init.h> contains
section definitions for use in .S files.
Because modpost checks for missing SHF_ALLOC section flag. So just add
it.
Signed-off-by: WANG Cong <amwang@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The defines and typedefs (hw_interrupt_type, no_irq_type, irq_desc_t) have
been kept around for migration reasons. After more than two years it's
time to remove them finally.
This patch cleans up one of the remaining users. When all such patches
hit mainline we can remove the defines and typedefs finally.
Impact: cleanup
Convert the last remaining users to struct irq_chip and remove the
define.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
See ancient discussion at
http://marc.info/?l=user-mode-linux-devel&m=101990155831279&w=2
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=7854
Signed-off-by: Alan Cox <alan@linux.intel.com>
Reported-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Roland Kletzing <devzero@web.de>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The defines and typedefs (hw_interrupt_type, no_irq_type, irq_desc_t) have
been kept around for migration reasons. After more than two years it's
time to remove them finally.
This patch cleans up one of the remaining users. When all such patches
hit mainline we can remove the defines and typedefs finally.
Impact: cleanup
Convert the last remaining users to struct irq_chip and remove the
define.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
`for_each_mem_cluster(x, y, z)' will expand to
`for ((x) = (y)->x ...' but correct is `for ((x) = (y)->cluster ...'
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The defines and typedefs (hw_interrupt_type, no_irq_type, irq_desc_t) have
been kept around for migration reasons. After more than two years it's
time to remove them finally.
This patch cleans up one of the remaining users. When all such patches
hit mainline we can remove the defines and typedefs finally.
Impact: cleanup
Convert the last remaining users to struct irq_chip and remove the
define.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ALLOC_WMARK_MIN, ALLOC_WMARK_LOW and ALLOC_WMARK_HIGH determin whether
pages_min, pages_low or pages_high is used as the zone watermark when
allocating the pages. Two branches in the allocator hotpath determine
which watermark to use.
This patch uses the flags as an array index into a watermark array that is
indexed with WMARK_* defines accessed via helpers. All call sites that
use zone->pages_* are updated to use the helpers for accessing the values
and the array offsets for setting.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Callers of alloc_pages_node() can optionally specify -1 as a node to mean
"allocate from the current node". However, a number of the callers in
fast paths know for a fact their node is valid. To avoid a comparison and
branch, this patch adds alloc_pages_exact_node() that only checks the nid
with VM_BUG_ON(). Callers that know their node is valid are then
converted.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Paul Mundt <lethal@linux-sh.org> [for the SLOB NUMA bits]
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* create mm/init-mm.c, move init_mm there
* remove INIT_MM, initialize init_mm with C99 initializer
* unexport init_mm on all arches:
init_mm is already unexported on x86.
One strange place is some OMAP driver (drivers/video/omap/) which
won't build modular, but it's already wants get_vm_area() export.
Somebody should look there.
[akpm@linux-foundation.org: add missing #includes]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Mike Frysinger <vapier.adi@gmail.com>
Cc: Americo Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
PIT_TICK_RATE is currently defined in four architectures, but in three
different places. While linux/timex.h is not the perfect place for it, it
is still a reasonable replacement for those drivers that traditionally use
asm/timex.h to get CLOCK_TICK_RATE and expect it to be the PIT frequency.
Note that for Alpha, the actual value changed from 1193182UL to 1193180UL.
This is unlikely to make a difference, and probably can only improve
accuracy. There was a discussion on the correct value of CLOCK_TICK_RATE
a few years ago, after which every existing instance was getting changed
to 1193182. According to the specification, it should be
1193181.818181...
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Len Brown <lenb@kernel.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'timers-for-linus-migration' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
timers: Logic to move non pinned timers
timers: /proc/sys sysctl hook to enable timer migration
timers: Identifying the existing pinned timers
timers: Framework for identifying pinned timers
timers: allow deferrable timers for intervals tv2-tv5 to be deferred
Fix up conflicts in kernel/sched.c and kernel/timer.c manually
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (103 commits)
powerpc: Fix bug in move of altivec code to vector.S
powerpc: Add support for swiotlb on 32-bit
powerpc/spufs: Remove unused error path
powerpc: Fix warning when printing a resource_size_t
powerpc/xmon: Remove unused variable in xmon.c
powerpc/pseries: Fix warnings when printing resource_size_t
powerpc: Shield code specific to 64-bit server processors
powerpc: Separate PACA fields for server CPUs
powerpc: Split exception handling out of head_64.S
powerpc: Introduce CONFIG_PPC_BOOK3S
powerpc: Move VMX and VSX asm code to vector.S
powerpc: Set init_bootmem_done on NUMA platforms as well
powerpc/mm: Fix a AB->BA deadlock scenario with nohash MMU context lock
powerpc/mm: Fix some SMP issues with MMU context handling
powerpc: Add PTRACE_SINGLEBLOCK support
fbdev: Add PLB support and cleanup DCR in xilinxfb driver.
powerpc/virtex: Add ml510 reference design device tree
powerpc/virtex: Add Xilinx ML510 reference design support
powerpc/virtex: refactor intc driver and add support for i8259 cascading
powerpc/virtex: Add support for Xilinx PCI host bridge
...
ad6561dffa ("module: trim exception table on init
free.") put a bogus trim_init_extable() function into ia64 which didn't compile.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>
* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (417 commits)
MAINTAINERS: EB110ATX is not ebsa110
MAINTAINERS: update Eric Miao's email address and status
fb: add support of LCD display controller on pxa168/910 (base layer)
[ARM] 5552/1: ep93xx get_uart_rate(): use EP93XX_SYSCON_PWRCNT and EP93XX_SYSCON_PWRCN
[ARM] pxa/sharpsl_pm: zaurus needs generic pxa suspend/resume routines
[ARM] 5544/1: Trust PrimeCell resource sizes
[ARM] pxa/sharpsl_pm: cleanup of gpio-related code.
[ARM] pxa/sharpsl_pm: drop set_irq_type calls
[ARM] pxa/sharpsl_pm: merge pxa-specific code into generic one
[ARM] pxa/sharpsl_pm: merge the two sharpsl_pm.c since it's now pxa specific
[ARM] sa1100: remove unused collie_pm.c
[ARM] pxa: fix the conflicting non-static declarations of global_gpios[]
[ARM] 5550/1: Add default configure file for w90p910 platform
[ARM] 5549/1: Add clock api for w90p910 platform.
[ARM] 5548/1: Add gpio api for w90p910 platform
[ARM] 5551/1: Add multi-function pin api for w90p910 platform.
[ARM] Make ARM_VIC_NR depend on ARM_VIC
[ARM] 5546/1: ARM PL022 SSP/SPI driver v3
ARM: OMAP4: SMP: Update defconfig for OMAP4430
ARM: OMAP4: SMP: Enable SMP support for OMAP4430
...
Without this, the default implementation is a no op which is completely
wrong with a VIVT cache, and usage of sg_copy_buffer() produces
unpredictable results.
Tested-by: Sebastian Andrzej Siewior <bigeasy@breakpoint.cc>
CC: stable@kernel.org
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
fix the following 'make headers_check' warnings:
usr/include/asm-mn10300/setup.h:14: extern's make no sense in userspace
usr/include/asm-mn10300/setup.h:15: extern's make no sense in userspace
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
fix the following 'make headers_check' warning:
usr/include/asm-mn10300/ptrace.h:80: extern's make no sense in userspace
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/hskinnemoen/avr32-2.6:
avr32: Fix oops on unaligned user access
avr32: Add support for Mediama RMTx add-on board for ATNGW100
avr32: Change Atmel ATNGW100 config to add choice of add-on board
Fix MIMC200 board LCD init
avr32: Fix clash in ATMEL_USART_ flags
avr32: remove obsolete hw_interrupt_type
avr32: Solves problem with inverted MCI detect pin on Merisc board
atmel-mci: Add support for inverted detect pin
Fix interaction with new generic header stuff as added by:
commit 6103ec56c6
Author: Arnd Bergmann <arnd@arndb.de>
Date: Wed May 13 22:56:27 2009 +0000
asm-generic: add generic ABI headers
The problem is that asm/signal.h has been made to include asm-generic/signal.h,
but the redundant stuff from asm/signal.h has not been discarded, leading to
multiple redefinitions.
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (35 commits)
hwrng: timeriomem - Fix potential oops (request_mem_region/__devinit)
crypto: api - Use formatting of module name
crypto: testmgr - Allow hash test vectors longer than a page
crypto: testmgr - Check all test vector lengths
crypto: hifn_795x - fix __dev{init,exit} markings
crypto: tcrypt - Do not exit on success in fips mode
crypto: compress - Return produced bytes in crypto_{,de}compress_{update,final}
hwrng: via_rng - Support VIA Nano hardware RNG on X86_64 builds
hwrng: via_rng - Support VIA Nano hardware RNG
hwrng: via_rng - The VIA Hardware RNG driver is for the CPU, not Chipset
crypto: testmgr - Skip algs not flagged fips_allowed in fips mode
crypto: testmgr - Mark algs allowed in fips mode
crypto: testmgr - Add ctr(aes) test vectors
crypto: testmgr - Dynamically allocate xbuf and axbuf
crypto: testmgr - Print self-test pass notices in fips mode
crypto: testmgr - Catch base cipher self-test failures in fips mode
crypto: testmgr - Add ansi_cprng test vectors
crypto: testmgr - Add infrastructure for ansi_cprng self-tests
crypto: testmgr - Add self-tests for rfc4309(ccm(aes))
crypto: testmgr - Handle AEAD test vectors expected to fail verification
...
The unaligned address exception handler (and others) does not scan the
fixup tables before oopsing. This is bad because it means passing a
badly aligned pointer from user space might crash the kernel.
Fix this by scanning the fixup tables in _exception(). This should
resolve the issue for unaligned addresses as well as other less common
exceptions that might be happening during a userspace access. The page
fault handler already does fixup processing.
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
* 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6: (30 commits)
[S390] wire up sys_perf_counter_open
[S390] wire up sys_rt_tgsigqueueinfo
[S390] ftrace: add system call tracer support
[S390] ftrace: add function graph tracer support
[S390] ftrace: add function trace mcount test support
[S390] ftrace: add dynamic ftrace support
[S390] kprobes: use probe_kernel_write
[S390] maccess: arch specific probe_kernel_write() implementation
[S390] maccess: add weak attribute to probe_kernel_write
[S390] profile_tick called twice
[S390] dasd: forward internal errors to dasd_sleep_on caller
[S390] dasd: sync after async probe
[S390] dasd: check_characteristics cleanup
[S390] dasd: no High Performance FICON in 31-bit mode
[S390] dcssblk: revert devt conversion
[S390] qdio: fix access beyond ARRAY_SIZE of irq_ptr->{in,out}put_qs
[S390] vmalloc: add vmalloc kernel parameter support
[S390] uaccess: use might_fault() instead of might_sleep()
[S390] 3270: lock dependency fixes
[S390] 3270: do not register with tty_register_device
...
* 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf_counter: Start documenting HAVE_PERF_COUNTERS requirements
perf_counter: Add forward/backward attribute ABI compatibility
perf record: Explicity program a default counter
perf_counter: Remove PERF_TYPE_RAW special casing
perf_counter: PERF_TYPE_HW_CACHE is a hardware counter too
powerpc, perf_counter: Fix performance counter event types
perf_counter/x86: Add a quirk for Atom processors
perf_counter tools: Remove one L1-data alias
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/vapier/blackfin: (62 commits)
Blackfin: fix sparseirq/kstat_irqs fallout
Blackfin: fix unused warnings after nommu update
Blackfin: export the last exception cause via debugfs
Blackfin: fix length checking in kgdb_ebin2mem
Blackfin: kgdb: fix up error return values
Blackfin: push access_ok() L1 attribute down
Blackfin: punt duplicated search_exception_table() prototype
Blackfin: add missing access_ok() checks to user functions
Blackfin: convert early_printk EVT init to a loop
Blackfin: document the lsl variants of the L1 allocator
Blackfin: rename Blackfin relocs according to the toolchain
Blackfin: check SIC defines rather than variant names
Blackfin: add SSYNC to set_dma_sg() for descriptor fetching
Blackfin: convert SMP to only use generic time framework
Blackfin: bf548-ezkit/bf537-stamp: add resources for ADXL345/346
Blackfin: override default uClinux MTD addr/size
Blackfin: fix command line corruption with DEBUG_DOUBLEFAULT
Blackfin: fix handling of initial L1 reservation
Blackfin: merge sram init functions
Blackfin: drop unused reserve_pda() function
...
This patch (as1241) renames a bunch of functions in the PM core.
Rather than go through a boring list of name changes, suffice it to
say that in the end we have a bunch of pairs of functions:
device_resume_noirq dpm_resume_noirq
device_resume dpm_resume
device_complete dpm_complete
device_suspend_noirq dpm_suspend_noirq
device_suspend dpm_suspend
device_prepare dpm_prepare
in which device_X does the X operation on a single device and dpm_X
invokes device_X for all devices in the dpm_list.
In addition, the old dpm_power_up and device_resume_noirq have been
combined into a single function (dpm_resume_noirq).
Lastly, dpm_suspend_start and dpm_resume_end are the renamed versions
of the former top-level device_suspend and device_resume routines.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Rename the functions performing "_noirq" dev_pm_ops
operations from device_power_down() and device_power_up()
to device_suspend_noirq() and device_resume_noirq().
The new function names are chosen to show that the functions
are responsible for calling the _noirq() versions to finalize
the suspend/resume operation. The current function names do
not perform power down/up anymore so the names may be misleading.
Global function renames:
- device_power_down() -> device_suspend_noirq()
- device_power_up() -> device_resume_noirq()
Static function renames:
- suspend_device_noirq() -> __device_suspend_noirq()
- resume_device_noirq() -> __device_resume_noirq()
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Len Brown <lenb@kernel.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This patch removes unused asm/suspend.h files for
the following architectures:
alpha, arm, ia64, m68k, mips, s390, um
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This is the last unification step. Here we do remove one of the files
and rename the left one as cpu.c, as both are now the same.
Also update power/Makefile, telling it to build cpu.o, instead of
cpu_(32|64).o
Signed-off-by: Sergio Luis <sergio@larces.uece.br>
Signed-off-by: Lauro Salmito <laurosalmito@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
In this step, we do unify the copyright notes for both files
cpu_32.c and cpu_64.c, making such files exactly the same.
It's the last step before the actual unification, that will
rename one of them to cpu.c and remove the other one.
Signed-off-by: Sergio Luis <sergio@larces.uece.br>
Signed-off-by: Lauro Salmito <laurosalmito@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
In this step we do unify cpu_32.c and cpu_64.c functions that
work on restoring the saved processor state. Also, we do
eliminate the forward declaration of fix_processor_context()
for X86_64, as it's not needed anymore.
Signed-off-by: Sergio Luis <sergio@larces.uece.br>
Signed-off-by: Lauro Salmito <laurosalmito@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
In this step we do unify cpu_32.c and cpu_64.c functions that
work on saving the processor state.
Signed-off-by: Sergio Luis <sergio@larces.uece.br>
Signed-off-by: Lauro Salmito <laurosalmito@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Aiming total unification of cpu_32.c and cpu_64.c, in this step
we do unify the global variables and existing forward declarations
for such files.
Signed-off-by: Sergio Luis <sergio@larces.uece.br>
Signed-off-by: Lauro Salmito <laurosalmito@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Minchan Kim