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2007-05-07Merge git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6Linus Torvalds7-7/+48
* git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6: [IA64] update memory attribute aliasing documentation & test cases [IA64] fail mmaps that span areas with incompatible attributes [IA64] allow WB /sys/.../legacy_mem mmaps [IA64] make ioremap avoid unsupported attributes [IA64] rename ioremap variables to match i386 [IA64] relax per-cpu TLB requirement to DTC [IA64] remove per-cpu ia64_phys_stacked_size_p8 [IA64] Fix example error injection program [IA64] Itanium MC Error Injection Tool: pal_mc_error_inject() interface [IA64] Itanium MC Error Injection Tool: Makefile changes [IA64] Itanium MC Error Injection Tool: Driver sysfs interface [IA64] Itanium MC Error Injection Tool: Doc and sample application [IA64] Itanium MC Error Injection Tool: Kernel configuration
2007-05-07Merge branch 'server-cluster-locking-api' of git://linux-nfs.org/~bfields/linuxLinus Torvalds3-5/+22
* 'server-cluster-locking-api' of git://linux-nfs.org/~bfields/linux: gfs2: nfs lock support for gfs2 lockd: add code to handle deferred lock requests lockd: always preallocate block in nlmsvc_lock() lockd: handle test_lock deferrals lockd: pass cookie in nlmsvc_testlock lockd: handle fl_grant callbacks lockd: save lock state on deferral locks: add fl_grant callback for asynchronous lock return nfsd4: Convert NFSv4 to new lock interface locks: add lock cancel command locks: allow {vfs,posix}_lock_file to return conflicting lock locks: factor out generic/filesystem switch from setlock code locks: factor out generic/filesystem switch from test_lock locks: give posix_test_lock same interface as ->lock locks: make ->lock release private data before returning in GETLK case locks: create posix-to-flock helper functions locks: trivial removal of unnecessary parentheses
2007-05-07Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-nmwLinus Torvalds1-1/+8
* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-nmw: (34 commits) [GFS2] Uncomment sprintf_symbol calling code [DLM] lowcomms style [GFS2] printk warning fixes [GFS2] Patch to fix mmap of stuffed files [GFS2] use lib/parser for parsing mount options [DLM] Lowcomms nodeid range & initialisation fixes [DLM] Fix dlm_lowcoms_stop hang [DLM] fix mode munging [GFS2] lockdump improvements [GFS2] Patch to detect corrupt number of dir entries in leaf and/or inode blocks [GFS2] bz 236008: Kernel gpf doing cat /debugfs/gfs2/xxx (lock dump) [DLM] fs/dlm/ast.c should #include "ast.h" [DLM] Consolidate transport protocols [DLM] Remove redundant assignment [GFS2] Fix bz 234168 (ignoring rgrp flags) [DLM] change lkid format [DLM] interface for purge (2/2) [DLM] add orphan purging code (1/2) [DLM] split create_message function [GFS2] Set drop_count to 0 (off) by default ...
2007-05-07Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6Linus Torvalds1-0/+89
* master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6: [NET]: rfkill: add support for input key to control wireless radio [NET] net/core: Fix error handling [TG3]: Update version and reldate. [TG3]: Eliminate spurious interrupts. [TG3]: Add ASPM workaround. [Bluetooth] Correct SCO buffer for another Broadcom based dongle [Bluetooth] Add support for Targus ACB10US USB dongle [Bluetooth] Disconnect L2CAP connection after last RFCOMM DLC [Bluetooth] Check that device is in rfcomm_dev_list before deleting [Bluetooth] Use in-kernel sockets API [Bluetooth] Attach host adapters to the Bluetooth bus [Bluetooth] Fix L2CAP and HCI setsockopt() information leaks
2007-05-07Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6Linus Torvalds1-0/+1
* master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6: [SERIAL] sunsu: Fix section mismatch warnings. [SPARC64]: pgtable_cache_init() should be __init. [SPARC64]: Fix section mismatch warnings in arch/sparc64/kernel/prom.c [SPARC64]: Fix section mismatch warnings in arch/sparc64/kernel/pci.c [SPARC64]: Fix section mismatch warnings in arch/sparc64/kernel/console.c [MM]: sparse_init() should be __init. [SPARC64]: Update defconfig. [VIDEO]: Add Sun XVR-2500 framebuffer driver. [VIDEO]: Add Sun XVR-500 framebuffer driver. [SPARC64]: SUN4U PCI-E controller support. [SPARC]: Fix comment typo in smp4m_blackbox_current(). [SCSI] SUNESP: sun_esp.c needs linux/delay.h Fix up conflict in arch/sparc64/mm/init.c manually due to removal of pgtable_cache_init() through the -mm patches (even though that patch was also by David ;) Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07Merge branch 'for-linus' of ↵Linus Torvalds1-10/+37
master.kernel.org:/pub/scm/linux/kernel/git/roland/infiniband * 'for-linus' of master.kernel.org:/pub/scm/linux/kernel/git/roland/infiniband: IPoIB: Convert to NAPI IB: Return "maybe missed event" hint from ib_req_notify_cq() IB: Add CQ comp_vector support IB/ipath: Fix a race condition when generating ACKs IB/ipath: Fix two more spin lock problems IB/fmr_pool: Add prefix to all printks IB/srp: Set proc_name IB/srp: Add orig_dgid sysfs attribute to scsi_host IPoIB/cm: Don't crash if remote side uses one QP for both directions RDMA/cxgb3: Support for new abort logic RDMA/cxgb3: Initialize cpu_idx field in cpl_close_listserv_req message RDMA/cxgb3: Fail qp creation if the requested max_inline is too large RDMA/cxgb3: Fix TERM codes IPoIB/cm: Fix error handling in ipoib_cm_dev_open() IB/ipath: Don't corrupt pending mmap list when unmapped objects are freed IB/mthca: Work around kernel QP starvation IB/ipath: Don't put QP in timeout queue if waiting to send IB/ipath: Don't call spin_lock_irq() from interrupt context
2007-05-07Merge master.kernel.org:/pub/scm/linux/kernel/git/lethal/sh-2.6Linus Torvalds21-208/+523
* master.kernel.org:/pub/scm/linux/kernel/git/lethal/sh-2.6: (38 commits) sh: R7785RP board updates. sh: Update r7780rp defconfig. sh: Add die chain notifiers. sh: Fix APM emulation on hp6xx. sh: Wire up more IRQs for SH7709. sh: Solution Engine 7722 board support. sh: Fix r7780rp build. sh: kdump support. sh: Move clock reporting to its own proc entry. sh: Solution Engine SH7705 board and CPU updates. serial: sh-sci: Fix module clock refcount for serial console. serial: sh-sci: Fix module clock refcounting. sh: SH7722 clock framework support. sh: hp6xx pata_platform support. sh: Obey CONFIG_HZ for HZ definition. sh: Fix fstatat64() syscall. sh: se7780 PCI support. sh: SH7780 Solution Engine board support. sh: Add a dummy SH-4 PCIC fixup. sh: Tidy up L-BOX area5 addresses. ...
2007-05-07uml: more page fault path trimmingJeff Dike2-14/+13
More trimming of the page fault path. Permissions are passed around in a single int rather than one bit per int. The permission values are copied from libc so that they can be passed to mmap and mprotect without any further conversion. The register sets used by do_syscall_stub and copy_context_skas0 are initialized once, at boot time, rather than once per call. wait_stub_done checks whether it is getting the signals it expects by comparing the wait status to a mask containing bits for the signals of interest rather than comparing individually to the signal numbers. It also has one check for a wait failure instead of two. The caller is expected to do the initial continue of the stub. This gets rid of an argument and some logic. The fname argument is gone, as that can be had from a stack trace. user_signal() is collapsed into userspace() as it is basically one or two lines of code afterwards. The physical memory remapping stuff is gone, as it is unused. flush_tlb_page is inlined. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07uml: improve checking and diagnostics of ethernet MACsPaolo 'Blaisorblade' Giarrusso1-0/+12
Improve checking and diagnostics for broadcast and multicast Ethernet MAC addresses, and distinguish between those cases in output; also make sure the device is assigned a MAC address valid only locally to avoid collisions. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07ARRAY_SIZE: check for typeRusty Russell3-1/+8
We can use a gcc extension to ensure that ARRAY_SIZE() is handed an array, not a pointer. This is especially important when code is changed from a fixed array to a pointer. I assume the Intel compiler doesn't support __builtin_types_compatible_p. [jdike@addtoit.com: uml: update UML definition of ARRAY_SIZE] Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07swsusp: free more memoryRafael J. Wysocki1-6/+0
Move the definition of PAGES_FOR_IO to kernel/power/power.h and introduce SPARE_PAGES representing the number of pages that should be freed by the swsusp's memory shrinker in addition to PAGES_FOR_IO so that device drivers can allocate some memory (up to 1 MB total) in their .suspend() routines without causing the suspend to fail. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Nigel Cunningham <nigel@nigel.suspend2.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07remove software_suspend()Johannes Berg2-9/+1
Remove software_suspend() and all its users since pm_suspend(PM_SUSPEND_DISK) should be equivalent and there's no point in having two interfaces for the same thing. The patch also changes the valid_state function to return 0 (false) for PM_SUSPEND_DISK when SOFTWARE_SUSPEND is not configured instead of accepting it and having the whole thing fail later. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07mm: remove unused page flagsRafael J. Wysocki1-12/+0
Remove the two page flags that were previously used by swsusp and are no longer needed. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07swsusp: do not use page flagsRafael J. Wysocki1-40/+18
Make swsusp use memory bitmaps instead of page flags for marking 'nosave' and free pages. This allows us to 'recycle' two page flags that can be used for other purposes. Also, the memory needed to store the bitmaps is allocated when necessary (ie. before the suspend) and freed after the resume which is more reasonable. The patch is designed to minimize the amount of changes and there are some nice simplifications and optimizations possible on top of it. I am going to implement them separately in the future. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07swsusp: use inline functions for changing page flagsRafael J. Wysocki1-0/+33
Replace direct invocations of SetPageNosave(), SetPageNosaveFree() etc. with calls to inline functions that can be changed in subsequent patches without modifying the code calling them. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07ALPHA: "prctl" macrosIvan Kokshaysky1-0/+22
Files: include/asm-alpha/thread_info.h Provide "prctl" macros for ALPHA. Signed-off-by: Jay Estabrook <jay.estabrook@hp.com> Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Richard Henderson <rth@twiddle.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07h8300 generic irqYoshinori Sato3-1/+2
h8300 using generic irq handler patch. Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07blackfin: serial driverBryan Wu1-0/+3
This patch implements the driver necessary use the Analog Devices Blackfin processor's Serial Port. Signed-off-by: Bryan Wu <bryan.wu@analog.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Russell King <rmk+lkml@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07blackfin architectureBryan Wu144-0/+23352
This adds support for the Analog Devices Blackfin processor architecture, and currently supports the BF533, BF532, BF531, BF537, BF536, BF534, and BF561 (Dual Core) devices, with a variety of development platforms including those avaliable from Analog Devices (BF533-EZKit, BF533-STAMP, BF537-STAMP, BF561-EZKIT), and Bluetechnix! Tinyboards. The Blackfin architecture was jointly developed by Intel and Analog Devices Inc. (ADI) as the Micro Signal Architecture (MSA) core and introduced it in December of 2000. Since then ADI has put this core into its Blackfin processor family of devices. The Blackfin core has the advantages of a clean, orthogonal,RISC-like microprocessor instruction set. It combines a dual-MAC (Multiply/Accumulate), state-of-the-art signal processing engine and single-instruction, multiple-data (SIMD) multimedia capabilities into a single instruction-set architecture. The Blackfin architecture, including the instruction set, is described by the ADSP-BF53x/BF56x Blackfin Processor Programming Reference http://blackfin.uclinux.org/gf/download/frsrelease/29/2549/Blackfin_PRM.pdf The Blackfin processor is already supported by major releases of gcc, and there are binary and source rpms/tarballs for many architectures at: http://blackfin.uclinux.org/gf/project/toolchain/frs There is complete documentation, including "getting started" guides available at: http://docs.blackfin.uclinux.org/ which provides links to the sources and patches you will need in order to set up a cross-compiling environment for bfin-linux-uclibc This patch, as well as the other patches (toolchain, distribution, uClibc) are actively supported by Analog Devices Inc, at: http://blackfin.uclinux.org/ We have tested this on LTP, and our test plan (including pass/fails) can be found at: http://docs.blackfin.uclinux.org/doku.php?id=testing_the_linux_kernel [m.kozlowski@tuxland.pl: balance parenthesis in blackfin header files] Signed-off-by: Bryan Wu <bryan.wu@analog.com> Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl> Signed-off-by: Aubrey Li <aubrey.li@analog.com> Signed-off-by: Jie Zhang <jie.zhang@analog.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07page migration: Only migrate pages if allocation in the highest zone is possibleChristoph Lameter1-1/+14
Address spaces contain an allocation flag that specifies restriction on the zone for pages placed in the mapping. I.e. some device may require pages to be allocated from a DMA zone. Block devices may not be able to use pages from HIGHMEM. Memory policies and the common use of page migration works only on the highest zone. If the address space does not allow allocation from the highest zone then the pages in the address space are not migratable simply because we can only allocate memory for a specified node if we allow allocation for the highest zone on each node. Acked-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07Slab allocators: remove useless __GFP_NO_GROW flagChristoph Lameter1-2/+1
There is no user remaining and I have never seen any use of that flag. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07slab allocators: Remove SLAB_CTOR_ATOMICChristoph Lameter1-1/+0
SLAB_CTOR atomic is never used which is no surprise since I cannot imagine that one would want to do something serious in a constructor or destructor. In particular given that the slab allocators run with interrupts disabled. Actions in constructors and destructors are by their nature very limited and usually do not go beyond initializing variables and list operations. (The i386 pgd ctor and dtors do take a spinlock in constructor and destructor..... I think that is the furthest we go at this point.) There is no flag passed to the destructor so removing SLAB_CTOR_ATOMIC also establishes a certain symmetry. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07slab allocators: Remove SLAB_DEBUG_INITIAL flagChristoph Lameter1-2/+0
I have never seen a use of SLAB_DEBUG_INITIAL. It is only supported by SLAB. I think its purpose was to have a callback after an object has been freed to verify that the state is the constructor state again? The callback is performed before each freeing of an object. I would think that it is much easier to check the object state manually before the free. That also places the check near the code object manipulation of the object. Also the SLAB_DEBUG_INITIAL callback is only performed if the kernel was compiled with SLAB debugging on. If there would be code in a constructor handling SLAB_DEBUG_INITIAL then it would have to be conditional on SLAB_DEBUG otherwise it would just be dead code. But there is no such code in the kernel. I think SLUB_DEBUG_INITIAL is too problematic to make real use of, difficult to understand and there are easier ways to accomplish the same effect (i.e. add debug code before kfree). There is a related flag SLAB_CTOR_VERIFY that is frequently checked to be clear in fs inode caches. Remove the pointless checks (they would even be pointless without removeal of SLAB_DEBUG_INITIAL) from the fs constructors. This is the last slab flag that SLUB did not support. Remove the check for unimplemented flags from SLUB. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07KMEM_CACHE(): simplify slab cache creationChristoph Lameter1-0/+12
This patch provides a new macro KMEM_CACHE(<struct>, <flags>) to simplify slab creation. KMEM_CACHE creates a slab with the name of the struct, with the size of the struct and with the alignment of the struct. Additional slab flags may be specified if necessary. Example struct test_slab { int a,b,c; struct list_head; } __cacheline_aligned_in_smp; test_slab_cache = KMEM_CACHE(test_slab, SLAB_PANIC) will create a new slab named "test_slab" of the size sizeof(struct test_slab) and aligned to the alignment of test slab. If it fails then we panic. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07slab allocators: Remove obsolete SLAB_MUST_HWCACHE_ALIGNChristoph Lameter1-1/+0
This patch was recently posted to lkml and acked by Pekka. The flag SLAB_MUST_HWCACHE_ALIGN is 1. Never checked by SLAB at all. 2. A duplicate of SLAB_HWCACHE_ALIGN for SLUB 3. Fulfills the role of SLAB_HWCACHE_ALIGN for SLOB. The only remaining use is in sparc64 and ppc64 and their use there reflects some earlier role that the slab flag once may have had. If its specified then SLAB_HWCACHE_ALIGN is also specified. The flag is confusing, inconsistent and has no purpose. Remove it. Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07mm: optimize kill_bdev()Peter Zijlstra1-0/+1
Remove duplicate work in kill_bdev(). It currently invalidates and then truncates the bdev's mapping. invalidate_mapping_pages() will opportunistically remove pages from the mapping. And truncate_inode_pages() will forcefully remove all pages. The only thing truncate doesn't do is flush the bh lrus. So do that explicitly. This avoids (very unlikely) but possible invalid lookup results if the same bdev is quickly re-issued. It also will prevent extreme kernel latencies which are observed when blockdevs which have a large amount of pagecache are unmounted, by avoiding invalidate_mapping_pages() on that path. invalidate_mapping_pages() has no cond_resched (it can be called under spinlock), whereas truncate_inode_pages() has one. [akpm@linux-foundation.org: restore nrpages==0 optimisation] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07mm: remove destroy_dirty_buffers from invalidate_bdev()Peter Zijlstra1-2/+2
Remove the destroy_dirty_buffers argument from invalidate_bdev(), it hasn't been used in 6 years (so akpm says). find * -name \*.[ch] | xargs grep -l invalidate_bdev | while read file; do quilt add $file; sed -ie 's/invalidate_bdev(\([^,]*\),[^)]*)/invalidate_bdev(\1)/g' $file; done Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07Quicklist support for sparc64David Miller1-12/+14
I ported this to sparc64 as per the patch below, tested on UP SunBlade1500 and 24 cpu Niagara T1000. Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Andi Kleen <ak@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: William Lee Irwin III <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07Quicklists for page table pagesChristoph Lameter1-0/+94
On x86_64 this cuts allocation overhead for page table pages down to a fraction (kernel compile / editing load. TSC based measurement of times spend in each function): no quicklist pte_alloc 1569048 4.3s(401ns/2.7us/179.7us) pmd_alloc 780988 2.1s(337ns/2.7us/86.1us) pud_alloc 780072 2.2s(424ns/2.8us/300.6us) pgd_alloc 260022 1s(920ns/4us/263.1us) quicklist: pte_alloc 452436 573.4ms(8ns/1.3us/121.1us) pmd_alloc 196204 174.5ms(7ns/889ns/46.1us) pud_alloc 195688 172.4ms(7ns/881ns/151.3us) pgd_alloc 65228 9.8ms(8ns/150ns/6.1us) pgd allocations are the most complex and there we see the most dramatic improvement (may be we can cut down the amount of pgds cached somewhat?). But even the pte allocations still see a doubling of performance. 1. Proven code from the IA64 arch. The method used here has been fine tuned for years and is NUMA aware. It is based on the knowledge that accesses to page table pages are sparse in nature. Taking a page off the freelists instead of allocating a zeroed pages allows a reduction of number of cachelines touched in addition to getting rid of the slab overhead. So performance improves. This is particularly useful if pgds contain standard mappings. We can save on the teardown and setup of such a page if we have some on the quicklists. This includes avoiding lists operations that are otherwise necessary on alloc and free to track pgds. 2. Light weight alternative to use slab to manage page size pages Slab overhead is significant and even page allocator use is pretty heavy weight. The use of a per cpu quicklist means that we touch only two cachelines for an allocation. There is no need to access the page_struct (unless arch code needs to fiddle around with it). So the fast past just means bringing in one cacheline at the beginning of the page. That same cacheline may then be used to store the page table entry. Or a second cacheline may be used if the page table entry is not in the first cacheline of the page. The current code will zero the page which means touching 32 cachelines (assuming 128 byte). We get down from 32 to 2 cachelines in the fast path. 3. x86_64 gets lightweight page table page management. This will allow x86_64 arch code to faster repopulate pgds and other page table entries. The list operations for pgds are reduced in the same way as for i386 to the point where a pgd is allocated from the page allocator and when it is freed back to the page allocator. A pgd can pass through the quicklists without having to be reinitialized. 64 Consolidation of code from multiple arches So far arches have their own implementation of quicklist management. This patch moves that feature into the core allowing an easier maintenance and consistent management of quicklists. Page table pages have the characteristics that they are typically zero or in a known state when they are freed. This is usually the exactly same state as needed after allocation. So it makes sense to build a list of freed page table pages and then consume the pages already in use first. Those pages have already been initialized correctly (thus no need to zero them) and are likely already cached in such a way that the MMU can use them most effectively. Page table pages are used in a sparse way so zeroing them on allocation is not too useful. Such an implementation already exits for ia64. Howver, that implementation did not support constructors and destructors as needed by i386 / x86_64. It also only supported a single quicklist. The implementation here has constructor and destructor support as well as the ability for an arch to specify how many quicklists are needed. Quicklists are defined by an arch defining CONFIG_QUICKLIST. If more than one quicklist is necessary then we can define NR_QUICK for additional lists. F.e. i386 needs two and thus has config NR_QUICK int default 2 If an arch has requested quicklist support then pages can be allocated from the quicklist (or from the page allocator if the quicklist is empty) via: quicklist_alloc(<quicklist-nr>, <gfpflags>, <constructor>) Page table pages can be freed using: quicklist_free(<quicklist-nr>, <destructor>, <page>) Pages must have a definite state after allocation and before they are freed. If no constructor is specified then pages will be zeroed on allocation and must be zeroed before they are freed. If a constructor is used then the constructor will establish a definite page state. F.e. the i386 and x86_64 pgd constructors establish certain mappings. Constructors and destructors can also be used to track the pages. i386 and x86_64 use a list of pgds in order to be able to dynamically update standard mappings. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Andi Kleen <ak@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: William Lee Irwin III <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07slub: enable tracking of full slabsChristoph Lameter1-0/+1
If slab tracking is on then build a list of full slabs so that we can verify the integrity of all slabs and are also able to built list of alloc/free callers. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07Add virt_to_head_page and consolidate code in slab and slubChristoph Lameter1-0/+6
Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07mm: optimize compound_head() by avoiding a shared page flagChristoph Lameter2-20/+28
The patch adds PageTail(page) and PageHead(page) to check if a page is the head or the tail of a compound page. This is done by masking the two bits describing the state of a compound page and then comparing them. So one comparision and a branch instead of two bit checks and two branches. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07Make page->private usable in compound pagesChristoph Lameter2-5/+42
If we add a new flag so that we can distinguish between the first page and the tail pages then we can avoid to use page->private in the first page. page->private == page for the first page, so there is no real information in there. Freeing up page->private makes the use of compound pages more transparent. They become more usable like real pages. Right now we have to be careful f.e. if we are going beyond PAGE_SIZE allocations in the slab on i386 because we can then no longer use the private field. This is one of the issues that cause us not to support debugging for page size slabs in SLAB. Having page->private available for SLUB would allow more meta information in the page struct. I can probably avoid the 16 bit ints that I have in there right now. Also if page->private is available then a compound page may be equipped with buffer heads. This may free up the way for filesystems to support larger blocks than page size. We add PageTail as an alias of PageReclaim. Compound pages cannot currently be reclaimed. Because of the alias one needs to check PageCompound first. The RFC for the this approach was discussed at http://marc.info/?t=117574302800001&r=1&w=2 [nacc@us.ibm.com: fix hugetlbfs] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07SLUB: allocate smallest object size if the user asks for 0 bytesChristoph Lameter1-2/+6
Makes SLUB behave like SLAB in this area to avoid issues.... Throw a stack dump to alert people. At some point the behavior should be switched back. NULL is no memory as far as I can tell and if the use asked for 0 bytes then he need to get no memory. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07SLUB coreChristoph Lameter4-6/+229
This is a new slab allocator which was motivated by the complexity of the existing code in mm/slab.c. It attempts to address a variety of concerns with the existing implementation. A. Management of object queues A particular concern was the complex management of the numerous object queues in SLAB. SLUB has no such queues. Instead we dedicate a slab for each allocating CPU and use objects from a slab directly instead of queueing them up. B. Storage overhead of object queues SLAB Object queues exist per node, per CPU. The alien cache queue even has a queue array that contain a queue for each processor on each node. For very large systems the number of queues and the number of objects that may be caught in those queues grows exponentially. On our systems with 1k nodes / processors we have several gigabytes just tied up for storing references to objects for those queues This does not include the objects that could be on those queues. One fears that the whole memory of the machine could one day be consumed by those queues. C. SLAB meta data overhead SLAB has overhead at the beginning of each slab. This means that data cannot be naturally aligned at the beginning of a slab block. SLUB keeps all meta data in the corresponding page_struct. Objects can be naturally aligned in the slab. F.e. a 128 byte object will be aligned at 128 byte boundaries and can fit tightly into a 4k page with no bytes left over. SLAB cannot do this. D. SLAB has a complex cache reaper SLUB does not need a cache reaper for UP systems. On SMP systems the per CPU slab may be pushed back into partial list but that operation is simple and does not require an iteration over a list of objects. SLAB expires per CPU, shared and alien object queues during cache reaping which may cause strange hold offs. E. SLAB has complex NUMA policy layer support SLUB pushes NUMA policy handling into the page allocator. This means that allocation is coarser (SLUB does interleave on a page level) but that situation was also present before 2.6.13. SLABs application of policies to individual slab objects allocated in SLAB is certainly a performance concern due to the frequent references to memory policies which may lead a sequence of objects to come from one node after another. SLUB will get a slab full of objects from one node and then will switch to the next. F. Reduction of the size of partial slab lists SLAB has per node partial lists. This means that over time a large number of partial slabs may accumulate on those lists. These can only be reused if allocator occur on specific nodes. SLUB has a global pool of partial slabs and will consume slabs from that pool to decrease fragmentation. G. Tunables SLAB has sophisticated tuning abilities for each slab cache. One can manipulate the queue sizes in detail. However, filling the queues still requires the uses of the spin lock to check out slabs. SLUB has a global parameter (min_slab_order) for tuning. Increasing the minimum slab order can decrease the locking overhead. The bigger the slab order the less motions of pages between per CPU and partial lists occur and the better SLUB will be scaling. G. Slab merging We often have slab caches with similar parameters. SLUB detects those on boot up and merges them into the corresponding general caches. This leads to more effective memory use. About 50% of all caches can be eliminated through slab merging. This will also decrease slab fragmentation because partial allocated slabs can be filled up again. Slab merging can be switched off by specifying slub_nomerge on boot up. Note that merging can expose heretofore unknown bugs in the kernel because corrupted objects may now be placed differently and corrupt differing neighboring objects. Enable sanity checks to find those. H. Diagnostics The current slab diagnostics are difficult to use and require a recompilation of the kernel. SLUB contains debugging code that is always available (but is kept out of the hot code paths). SLUB diagnostics can be enabled via the "slab_debug" option. Parameters can be specified to select a single or a group of slab caches for diagnostics. This means that the system is running with the usual performance and it is much more likely that race conditions can be reproduced. I. Resiliency If basic sanity checks are on then SLUB is capable of detecting common error conditions and recover as best as possible to allow the system to continue. J. Tracing Tracing can be enabled via the slab_debug=T,<slabcache> option during boot. SLUB will then protocol all actions on that slabcache and dump the object contents on free. K. On demand DMA cache creation. Generally DMA caches are not needed. If a kmalloc is used with __GFP_DMA then just create this single slabcache that is needed. For systems that have no ZONE_DMA requirement the support is completely eliminated. L. Performance increase Some benchmarks have shown speed improvements on kernbench in the range of 5-10%. The locking overhead of slub is based on the underlying base allocation size. If we can reliably allocate larger order pages then it is possible to increase slub performance much further. The anti-fragmentation patches may enable further performance increases. Tested on: i386 UP + SMP, x86_64 UP + SMP + NUMA emulation, IA64 NUMA + Simulator SLUB Boot options slub_nomerge Disable merging of slabs slub_min_order=x Require a minimum order for slab caches. This increases the managed chunk size and therefore reduces meta data and locking overhead. slub_min_objects=x Mininum objects per slab. Default is 8. slub_max_order=x Avoid generating slabs larger than order specified. slub_debug Enable all diagnostics for all caches slub_debug=<options> Enable selective options for all caches slub_debug=<o>,<cache> Enable selective options for a certain set of caches Available Debug options F Double Free checking, sanity and resiliency R Red zoning P Object / padding poisoning U Track last free / alloc T Trace all allocs / frees (only use for individual slabs). To use SLUB: Apply this patch and then select SLUB as the default slab allocator. [hugh@veritas.com: fix an oops-causing locking error] [akpm@linux-foundation.org: various stupid cleanups and small fixes] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07i386: use page allocator to allocate thread_info structureChristoph Lameter1-3/+5
i386 uses kmalloc to allocate the threadinfo structure assuming that the allocations result in a page sized aligned allocation. That has worked so far because SLAB exempts page sized slabs from debugging and aligns them in special ways that goes beyond the restrictions imposed by KMALLOC_ARCH_MINALIGN valid for other slabs in the kmalloc array. SLUB also works fine without debugging since page sized allocations neatly align at page boundaries. However, if debugging is switched on then SLUB will extend the slab with debug information. The resulting slab is not longer of page size. It will only be aligned following the requirements imposed by KMALLOC_ARCH_MINALIGN. As a result the threadinfo structure may not be page aligned which makes i386 fail to boot with SLUB debug on. Replace the calls to kmalloc with calls into the page allocator. An alternate solution may be to create a custom slab cache where the alignment is set to PAGE_SIZE. That would allow slub debugging to be applied to the threadinfo structure. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07readahead: code cleanupJan Kara1-2/+2
Rename file_ra_state.prev_page to prev_index and file_ra_state.offset to prev_offset. Also update of prev_index in do_generic_mapping_read() is now moved close to the update of prev_offset. [wfg@mail.ustc.edu.cn: fix it] Signed-off-by: Jan Kara <jack@suse.cz> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: WU Fengguang <wfg@mail.ustc.edu.cn> Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07readahead: improve heuristic detecting sequential readsJan Kara1-0/+1
Introduce ra.offset and store in it an offset where the previous read ended. This way we can detect whether reads are really sequential (and thus we should not mark the page as accessed repeatedly) or whether they are random and just happen to be in the same page (and the page should really be marked accessed again). Signed-off-by: Jan Kara <jack@suse.cz> Acked-by: Nick Piggin <nickpiggin@yahoo.com.au> Cc: WU Fengguang <wfg@mail.ustc.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07smaps: add clear_refs file to clear referenceDavid Rientjes1-0/+1
Adds /proc/pid/clear_refs. When any non-zero number is written to this file, pte_mkold() and ClearPageReferenced() is called for each pte and its corresponding page, respectively, in that task's VMAs. This file is only writable by the user who owns the task. It is now possible to measure _approximately_ how much memory a task is using by clearing the reference bits with echo 1 > /proc/pid/clear_refs and checking the reference count for each VMA from the /proc/pid/smaps output at a measured time interval. For example, to observe the approximate change in memory footprint for a task, write a script that clears the references (echo 1 > /proc/pid/clear_refs), sleeps, and then greps for Pgs_Referenced and extracts the size in kB. Add the sizes for each VMA together for the total referenced footprint. Moments later, repeat the process and observe the difference. For example, using an efficient Mozilla: accumulated time referenced memory ---------------- ----------------- 0 s 408 kB 1 s 408 kB 2 s 556 kB 3 s 1028 kB 4 s 872 kB 5 s 1956 kB 6 s 416 kB 7 s 1560 kB 8 s 2336 kB 9 s 1044 kB 10 s 416 kB This is a valuable tool to get an approximate measurement of the memory footprint for a task. Cc: Hugh Dickins <hugh@veritas.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> [akpm@linux-foundation.org: build fixes] [mpm@selenic.com: rename for_each_pmd] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07i386: use pte_update_defer in ptep_test_and_clear_{dirty,young}Zachary Amsden1-20/+18
If you actually clear the bit, you need to: + pte_update_defer(vma->vm_mm, addr, ptep); The reason is, when updating PTEs, the hypervisor must be notified. Using atomic operations to do this is fine for all hypervisors I am aware of. However, for hypervisors which shadow page tables, if these PTE modifications are not trapped, you need a post-modification call to fulfill the update of the shadow page table. Acked-by: Zachary Amsden <zach@vmware.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07i386: add ptep_test_and_clear_{dirty,young}David Rientjes1-8/+17
Add ptep_test_and_clear_{dirty,young} to i386. They advertise that they have it and there is at least one place where it needs to be called without the page table lock: to clear the accessed bit on write to /proc/pid/clear_refs. ptep_clear_flush_{dirty,young} are updated to use the new functions. The overall net effect to current users of ptep_clear_flush_{dirty,young} is that we introduce an additional branch. Cc: Hugh Dickins <hugh@veritas.com> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: David Rientjes <rientjes@google.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07Add unitialized_var() macro for suppressing gcc warningsBorislav Petkov3-0/+14
Introduce a macro for suppressing gcc from generating a warning about a probable uninitialized state of a variable. Example: - spinlock_t *ptl; + spinlock_t *uninitialized_var(ptl); Not a happy solution, but those warnings are obnoxious. - Using the usual pointlessly-set-it-to-zero approach wastes several bytes of text. - Using a macro means we can (hopefully) do something else if gcc changes cause the `x = x' hack to stop working - Using a macro means that people who are worried about hiding true bugs can easily turn it off. Signed-off-by: Borislav Petkov <bbpetkov@yahoo.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07add pfn_valid_within helper for sub-MAX_ORDER hole detectionAndy Whitcroft1-0/+12
Generally we work under the assumption that memory the mem_map array is contigious and valid out to MAX_ORDER_NR_PAGES block of pages, ie. that if we have validated any page within this MAX_ORDER_NR_PAGES block we need not check any other. This is not true when CONFIG_HOLES_IN_ZONE is set and we must check each and every reference we make from a pfn. Add a pfn_valid_within() helper which should be used when scanning pages within a MAX_ORDER_NR_PAGES block when we have already checked the validility of the block normally with pfn_valid(). This can then be optimised away when we do not have holes within a MAX_ORDER_NR_PAGES block of pages. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Bob Picco <bob.picco@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07mm/slab.c: proper prototypesAdrian Bunk1-0/+3
Add proper prototypes in include/linux/slab.h. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07Introduce CONFIG_HAS_DMAHeiko Carstens1-2/+0
Architectures that don't support DMA can say so by adding a config NO_DMA to their Kconfig file. This will prevent compilation of some dma specific driver code. Also dma-mapping-broken.h isn't needed anymore on at least s390. This avoids compilation and linking of otherwise dead/broken code. Other architectures that include dma-mapping-broken.h are arm26, h8300, m68k, m68knommu and v850. If these could be converted as well we could get rid of the header file. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> "John W. Linville" <linville@tuxdriver.com> Cc: Kyle McMartin <kyle@parisc-linux.org> Cc: <James.Bottomley@SteelEye.com> Cc: Tejun Heo <htejun@gmail.com> Cc: Jeff Garzik <jeff@garzik.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: <geert@linux-m68k.org> Cc: <zippel@linux-m68k.org> Cc: <spyro@f2s.com> Cc: <uclinux-v850@lsi.nec.co.jp> Cc: <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07mm: make read_cache_page synchronousNick Piggin1-0/+11
Ensure pages are uptodate after returning from read_cache_page, which allows us to cut out most of the filesystem-internal PageUptodate calls. I didn't have a great look down the call chains, but this appears to fixes 7 possible use-before uptodate in hfs, 2 in hfsplus, 1 in jfs, a few in ecryptfs, 1 in jffs2, and a possible cleared data overwritten with readpage in block2mtd. All depending on whether the filler is async and/or can return with a !uptodate page. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07mm: remove gcc workaroundNick Piggin1-0/+18
Minimum gcc version is 3.2 now. However, with likely profiling, even modern gcc versions cannot always eliminate the call. Replace the placeholder functions with the more conventional empty static inlines, which should be optimal for everyone. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07proper prototype for hugetlb_get_unmapped_area()Adrian Bunk1-0/+6
Add a proper prototype for hugetlb_get_unmapped_area() in include/linux/hugetlb.h. Signed-off-by: Adrian Bunk <bunk@stusta.de> Acked-by: William Irwin <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07Add apply_to_page_range() which applies a function to a pte rangeJeremy Fitzhardinge1-0/+5
Add a new mm function apply_to_page_range() which applies a given function to every pte in a given virtual address range in a given mm structure. This is a generic alternative to cut-and-pasting the Linux idiomatic pagetable walking code in every place that a sequence of PTEs must be accessed. Although this interface is intended to be useful in a wide range of situations, it is currently used specifically by several Xen subsystems, for example: to ensure that pagetables have been allocated for a virtual address range, and to construct batched special pagetable update requests to map I/O memory (in ioremap()). [akpm@linux-foundation.org: fix warning, unpleasantly] Signed-off-by: Ian Pratt <ian.pratt@xensource.com> Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: Matt Mackall <mpm@waste.org> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07serial: define FIXED_PORT flag for serial_coreDavid Gibson1-0/+1
At present, the serial core always allows setserial in userspace to change the port address, irq and base clock of any serial port. That makes sense for legacy ISA ports, but not for (say) embedded ns16550 compatible serial ports at peculiar addresses. In these cases, the kernel code configuring the ports must know exactly where they are, and their clocking arrangements (which can be unusual on embedded boards). It doesn't make sense for userspace to change these settings. Therefore, this patch defines a UPF_FIXED_PORT flag for the uart_port structure. If this flag is set when the serial port is configured, any attempts to alter the port's type, io address, irq or base clock with setserial are ignored. In addition this patch uses the new flag for on-chip serial ports probed in arch/powerpc/kernel/legacy_serial.c, and for other hard-wired serial ports probed by drivers/serial/of_serial.c. Signed-off-by: David Gibson <dwg@au1.ibm.com> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>