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* gru: add debug option for cache flushingJack Steiner2009-12-162-5/+10
| | | | | | | | | | Add a debug option to the SGI GRU driver for flushing GRU cache lines from memory. In theory this is not needed but it is useful for debugging. This has no use by end users. Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gru: handle failures to mmu_notifier_registerJack Steiner2009-12-163-11/+21
| | | | | | | | | Under some conditions, mmu_notifier_register() will fail to register a mmu_notifier. Fix the GRU driver to correctly handle these failures. Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gru: support 64-bit GRU addressesJack Steiner2009-12-161-6/+0
| | | | | | | | | | Increase the maximum address supported by the SGI GRU driver to a full 64 bits. Note that GRU addresses are not always the same as socket virtual addresses. Sockets may not necessarily support the full 64 bits. Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gru: improve messages for malfunctioning GRUsJack Steiner2009-12-162-3/+25
| | | | | | | | | Improve error messages for malfunctioning GRUs. Identify the type of instruction that is failing. Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gru: fix bug in module unloadJack Steiner2009-12-161-1/+1
| | | | | | | | | Fix bug in module unload. Previous code was not correctly deleting the files in /proc. Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gru: allow users to specify gru chiplet 3Jack Steiner2009-12-163-29/+13
| | | | | | | | | | | | | | This patch builds on the infrastructure introduced in the patches that allow user specification of GRU blades & chiplets for context allocation. This patch simplifies the algorithms for migrating GRU contexts between blades. No new functionality is introduced. Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gru: allow users to specify gru chiplet 2Jack Steiner2009-12-166-80/+109
| | | | | | | | | | | Add support to the GRU driver to allow users to specify the blade & chiplet for allocation of GRU contexts. Add new statistics for context loading/unloading/retargeting. Also deleted a few GRU stats that were no longer being unused. Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gru: allow users to specify gru chiplet 1Jack Steiner2009-12-164-2/+17
| | | | | | | | | | Add table & user request infrastructure that is needed to allow users to specify the blade and chiplet for allocation of GRU contexts. Use of this information is in a subsequent patch. Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gru: handle blades without memoryJack Steiner2009-12-161-2/+2
| | | | | | | | | Do not use alloc_pages_exact_node() to allocate GRU tables. If a blade has no local memory, nid will be -1. Use alloc_pages_node() instead. Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gru: fix istatus race in GRU tlb dropinJack Steiner2009-12-161-29/+20
| | | | | | | | | | | | | | | | | | TLB dropins require updates to the CBR instruction istatus field. This is needed to resolve race conditions in the chip. The code currently uses the user address of the CBR. This works but opens up additional endcases related to stealing of contexts and accessing the CBR from tasks that do not have access to the user address space. (Some of this non-user task access is debug code that is not currently being pushed to the community). User CBRs are also directly accessible using the kernel mapping of the CBR. Change the TLB dropin code to use the the kernel mapping of the CBR. Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gru: add comments raised in previous code reviewsJack Steiner2009-12-162-1/+8
| | | | | | | | | | | Add comments from previous code reviews. The comments help explain some of the more esoteric aspects of the driver. Move a free() to the other side of an unlock. Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gru: initial GRU based on blade topologyJack Steiner2009-12-161-7/+5
| | | | | | | | | | Change the GRU initialization code to initialize based on blade topology instead of node topology. The result is the same but blade-based initialization is cleaner. Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* UV - XPC: pass nasid instead of nid to gru_create_message_queueRobin Holt2009-12-161-1/+4
| | | | | | | | | | Currently, the UV xpc code is passing nid to the gru_create_message_queue instead of nasid as it expects. Signed-off-by: Robin Holt <holt@sgi.com> Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* x86: uv: XPC receive message reuse triggers invalid BUG_ON()Robin Holt2009-12-161-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This was a difficult bug to trip. XPC was in the middle of sending an acknowledgement for a received message. In xpc_received_payload_uv(): . ret = xpc_send_gru_msg(ch->sn.uv.cached_notify_gru_mq_desc, msg, sizeof(struct xpc_notify_mq_msghdr_uv)); if (ret != xpSuccess) XPC_DEACTIVATE_PARTITION(&xpc_partitions[ch->partid], ret); msg->hdr.msg_slot_number += ch->remote_nentries; at the point in xpc_send_gru_msg() where the hardware has dispatched the acknowledgement, the remote side is able to reuse the message structure and send a message with a different slot number. This problem is made worse by interrupts. The adjustment of msg_slot_number and the BUG_ON in xpc_handle_notify_mq_msg_uv() which verifies the msg_slot_number is consistent are only used for debug purposes. Since a fix for this that preserves the debug functionality would either have to infringe upon the payload or allocate another structure just for debug, I decided to remove it entirely. Signed-off-by: Robin Holt <holt@sgi.com> Cc: Jack Steiner <steiner@sgi.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* X86: uv: xpc_make_first_contact hang due to not accepting ACTIVE stateRobin Holt2009-12-161-1/+2
| | | | | | | | | | | | | | | | | Many times while the initial connection is being made, the contacted partition will send back both the ACTIVATING and the ACTIVE remote_act_state changes in very close succescion. The 1/4 second delay in the make first contact loop is large enough to nearly always miss the ACTIVATING state change. Since either state indicates the remote partition has acknowledged our state change, accept either. Signed-off-by: Robin Holt <holt@sgi.com> Cc: Jack Steiner <steiner@sgi.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* x86: uv: xpc NULL deref when mesq becomes emptyRobin Holt2009-12-161-3/+5
| | | | | | | | | | | | Under heavy load conditions, our set of xpc messages may become exhausted. The code handles this correctly with the exception of the management code which hits a NULL pointer dereference. Signed-off-by: Robin Holt <holt@sgi.com> Cc: Jack Steiner <steiner@sgi.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* x86: uv: update XPC to handle updated BIOS interfaceRobin Holt2009-12-165-32/+50
| | | | | | | | | | | | | | | | | The UV BIOS has moved the location of some of their pointers to the "partition reserved page" from memory into a uv hub MMR. The GRU does not support bcopy operations from MMR space so we need to special case the MMR addresses using VLOAD operations. Additionally, the BIOS call for registering a message queue watchlist has removed the 'blade' value and eliminated the structure that was being passed in. This is also reflected in this patch. Signed-off-by: Robin Holt <holt@sgi.com> Cc: Jack Steiner <steiner@sgi.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* X86: uv: implement a gru_read_gpa kernel functionRobin Holt2009-12-165-0/+52
| | | | | | | | | | | | The BIOS has decided to store a pointer to the partition reserved page in a scratch MMR. The GRU is only able to read an MMR using a vload instruction. The gru_read_gpa() function will implemented. Signed-off-by: Robin Holt <holt@sgi.com> Signed-off-by: Jack Steiner <steiner@sgi.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* x86: uv: introduce uv_gpa_is_mmrRobin Holt2009-12-161-0/+7
| | | | | | | | | | | Provide a mechanism for determining if a global physical address is pointing to a UV hub MMR. Signed-off-by: Robin Holt <holt@sgi.com> Cc: Jack Steiner <steiner@sgi.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* x86: uv: xpc needs to provide an abstraction for uv_gpaRobin Holt2009-12-164-0/+24
| | | | | | | | | | | Provide an SGI SN2/UV agnositic method for converting a global physical address into a socket physical address. Signed-off-by: Robin Holt <holt@sgi.com> Cc: Jack Steiner <steiner@sgi.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* x86: uv: introduce a means to translate from gpa -> socket_paddrRobin Holt2009-12-161-0/+13
| | | | | | | | | | | | | | | | | | | | The UV BIOS has been updated to implement some of our interface functionality differently than originally expected. These patches update the kernel to the bios implementation and include a few minor bug fixes which prevent us from doing significant testing on real hardware. This patch: For SGI UV systems, translate from a global physical address back to a socket physical address. This does nothing to ensure the socket physical address is actually addressable by the kernel. That is the responsibility of the user of the function. Signed-off-by: Robin Holt <holt@sgi.com> Cc: Jack Steiner <steiner@sgi.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* direct-io: cleanup blockdev_direct_IO lockingChristoph Hellwig2009-12-164-134/+71
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the locking in blockdev_direct_IO is a mess, we have three different locking types and very confusing checks for some of them. The most complicated one is DIO_OWN_LOCKING for reads, which happens to not actually be used. This patch gets rid of the DIO_OWN_LOCKING - as mentioned above the read case is unused anyway, and the write side is almost identical to DIO_NO_LOCKING. The difference is that DIO_NO_LOCKING always sets the create argument for the get_blocks callback to zero, but we can easily move that to the actual get_blocks callbacks. There are four users of the DIO_NO_LOCKING mode: gfs already ignores the create argument and thus is fine with the new version, ocfs2 only errors out if create were ever set, and we can remove this dead code now, the block device code only ever uses create for an error message if we are fully beyond the device which can never happen, and last but not least XFS will need the new behavour for writes. Now we can replace the lock_type variable with a flags one, where no flag means the DIO_NO_LOCKING behaviour and DIO_LOCKING is kept as the first flag. Separate out the check for not allowing to fill holes into a separate flag, although for now both flags always get set at the same time. Also revamp the documentation of the locking scheme to actually make sense. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Zach Brown <zach.brown@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alex Elder <aelder@sgi.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <joel.becker@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* dio: don't zero out the pages array inside struct dioJeff Moyer2009-12-161-13/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Intel reported a performance regression caused by the following commit: commit 848c4dd5153c7a0de55470ce99a8e13a63b4703f Author: Zach Brown <zach.brown@oracle.com> Date: Mon Aug 20 17:12:01 2007 -0700 dio: zero struct dio with kzalloc instead of manually This patch uses kzalloc to zero all of struct dio rather than manually trying to track which fields we rely on being zero. It passed aio+dio stress testing and some bug regression testing on ext3. This patch was introduced by Linus in the conversation that lead up to Badari's minimal fix to manually zero .map_bh.b_state in commit: 6a648fa72161d1f6468dabd96c5d3c0db04f598a It makes the code a bit smaller. Maybe a couple fewer cachelines to load, if we're lucky: text data bss dec hex filename 3285925 568506 1304616 5159047 4eb887 vmlinux 3285797 568506 1304616 5158919 4eb807 vmlinux.patched I was unable to measure a stable difference in the number of cpu cycles spent in blockdev_direct_IO() when pushing aio+dio 256K reads at ~340MB/s. So the resulting intent of the patch isn't a performance gain but to avoid exposing ourselves to the risk of finding another field like .map_bh.b_state where we rely on zeroing but don't enforce it in the code. Zach surmised that zeroing out the page array was what caused most of the problem, and suggested the approach taken in the attached patch for resolving the issue. Intel re-tested with this patch and saw a 0.6% performance gain (the original regression was 0.5%). [akpm@linux-foundation.org: add comment] Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Acked-by: Zach Brown <zach.brown@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* aio: remove unused fieldShaohua Li2009-12-162-42/+2
| | | | | | | | | | | Don't know the reason, but it appears ki_wait field of iocb never gets used. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Zach Brown <zach.brown@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* FS-Cache: Avoid maybe-used-uninitialised warning on variableDavid Howells2009-12-161-1/+1
| | | | | | | | | | | | | | | | | | | Andrew Morton's compiler sees the following warning in FS-Cache: fs/fscache/object-list.c: In function 'fscache_objlist_lookup': fs/fscache/object-list.c:94: warning: 'obj' may be used uninitialized in this function which my compiler doesn't. This is a false positive as obj can only be used in the comparison against minobj if minobj has been set to something other than NULL, but for that to happen, obj has to be first set to something. Deal with this by preclearing obj too. Reported-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kexec: premit reduction of the reserved memory sizeAmerigo Wang2009-12-163-0/+82
| | | | | | | | | | | | | | | | | | | Implement shrinking the reserved memory for crash kernel, if it is more than enough. For example, if you have already reserved 128M, now you just want 100M, you can do: # echo $((100*1024*1024)) > /sys/kernel/kexec_crash_size Note, you can only do this before loading the crash kernel. Signed-off-by: WANG Cong <amwang@redhat.com> Cc: Neil Horman <nhorman@redhat.com> Acked-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* parport_pc.c: use correct length in strncmpJoe Perches2009-12-161-1/+1
| | | | | | | Signed-off-by: Joe Perches <joe@perches.com> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* dma-mapping: fix off-by-one error in dma_capable()Jan Beulich2009-12-164-5/+5
| | | | | | | | | | | | | | | | | | | dma_mask is, when interpreted as address, the last valid byte, and hence comparison msut also be done using the last valid of the buffer in question. Also fix the open-coded instances in lib/swiotlb.c. Signed-off-by: Jan Beulich <jbeulich@novell.com> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Becky Bruce <beckyb@kernel.crashing.org> Cc: "Luck, Tony" <tony.luck@intel.com> 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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* edac: i5100 add 6 ranks per channelNils Carlson2009-12-161-16/+20
| | | | | | | | | | | | Add support for 6 ranks per channel to the i5100 chipset. I have tested the patch as far as possible with correctible errors and things appear good. The DIMM mapping is correct for our board, but boards may differ. Signed-off-by: Nils Carlson <nils.carlson@ludd.ltu.se> Acked-by: Arthur Jones <ajones@riverbed.com> Signed-off-by: Doug Thompson <dougthompson@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* edac: i5100 add scrubbingNils Carlson2009-12-161-2/+110
| | | | | | | | | | | | | | | | | | | Addscrubbing to the i5100 chipset. The i5100 chipset only supports one scrubbing rate, which is not constant but dependent on memory load. The rate returned by this driver is an estimate based on some experimentation, but is substantially closer to the truth than the speed supplied in the documentation. Also, scrubbing is done once, and then a done-bit is set. This means that to accomplish continuous scrubbing a re-enabling mechanism must be used. I have created the simplest possible such mechanism in the form of a work-queue which will check every five minutes. This interval is quite arbitrary but should be sufficient for all sizes of system memory. Signed-off-by: Nils Carlson <nils.carlson@ludd.ltu.se> Signed-off-by: Doug Thompson <dougthompson@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* edac: i5100 clean controller to channel termsNils Carlson2009-12-161-55/+55
| | | | | | | | | | The i5100 driver uses the word controller instead of channel in a lot of places, this is simply a cleanup of the patch. Signed-off-by: Nils Carlson <nils.carlson@ludd.ltu.se> Signed-off-by: Doug Thompson <dougthompson@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pid: reduce code size by using a pointer to iterate over arrayAndré Goddard Rosa2009-12-161-3/+2
| | | | | | | | | | | | | It decreases code size by 16 bytes on my gcc 4.4.1 on Core 2: text data bss dec hex filename 4314 2216 8 6538 198a kernel/pid.o-BEFORE 4298 2216 8 6522 197a kernel/pid.o-AFTER Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pid: tighten pidmap spinlock critical section by removing kfree()André Goddard Rosa2009-12-161-3/+4
| | | | | | | | | | | | | Avoid calling kfree() under pidmap spinlock, calling it afterwards. Normally kfree() is fast, but sometimes it can be slow, so avoid calling it under the spinlock if we can do it. Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* elf: kill USE_ELF_CORE_DUMPChristoph Hellwig2009-12-1629-44/+9
| | | | | | | | | | | | | Currently all architectures but microblaze unconditionally define USE_ELF_CORE_DUMP. The microblaze omission seems like an error to me, so let's kill this ifdef and make sure we are the same everywhere. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: <linux-arch@vger.kernel.org> Cc: Michal Simek <michal.simek@petalogix.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* drivers/char/ipmi: Use KCS_IDLE_STATEJulia Lawall2009-12-161-1/+1
| | | | | | | | | | KCS_IDLE and KCS_IDLE state have the same value, but in this function the constants ending in _STATE are compared to the state variable. Signed-off-by: Julia Lawall <julia@diku.dk> Acked-by: Core Minyard <cminyard@mvista.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: HARD_MSGMAX should be higher not lower on 64bitAmerigo Wang2009-12-161-1/+1
| | | | | | | | | | | | | | We have HARD_MSGMAX lower on 64bit than on 32bit, since usually 64bit machines have more memory than 32bit machines. Making it higher on 64bit seems reasonable, and keep the original number on 32bit. Acked-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: WANG Cong <amwang@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: remove unreachable code in sem.cAmerigo Wang2009-12-161-2/+1
| | | | | | | | | This line is unreachable, remove it. [akpm@linux-foundation.org: remove unneeded initialisation of `err'] Signed-off-by: WANG Cong <amwang@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/sem.c: optimize single sops when semval is zeroManfred Spraul2009-12-161-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | If multiple simple decrements on the same semaphore are pending, then the current code scans all decrement operations, even if the semaphore value is already 0. The patch optimizes that: if the semaphore value is 0, then there is no need to scan the q->alter entries. Note that this is a common case: It happens if 100 decrements by one are pending and now an increment by one increases the semaphore value from 0 to 1. Without this patch, all 100 entries are scanned. With the patch, only one entry is scanned, then woken up. Then the new rule triggers and the scanning is aborted, without looking at the remaining 99 tasks. With this patch, single sop increment/decrement by 1 are now O(1). (same as with Nick's patch) Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Pierre Peiffer <peifferp@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/sem.c: optimize single semop operationsManfred Spraul2009-12-161-11/+40
| | | | | | | | | | | | | | | | | | | | | | sysv sem has the concept of semaphore arrays that consist out of multiple semaphores. Atomic operations that affect multiple semaphores are supported. The patch optimizes single semaphore operation calls that affect only one semaphore: It's not necessary to scan all pending operations, it is sufficient to scan the per-semaphore list. The idea is from Nick Piggin version of an ipc sem improvement, the implementation is different: The code tries to keep as much common code as possible. As the result, the patch is simpler, but optimizes fewer cases. Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Pierre Peiffer <peifferp@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/sem.c: add a per-semaphore pending listManfred Spraul2009-12-162-6/+36
| | | | | | | | | | | | | | | | | | | | | Based on Nick's findings: sysv sem has the concept of semaphore arrays that consist out of multiple semaphores. Atomic operations that affect multiple semaphores are supported. The patch is the first step for optimizing simple, single semaphore operations: In addition to the global list of all pending operations, a 2nd, per-semaphore list with the simple operations is added. Note: this patch does not make sense by itself, the new list is used nowhere. Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Pierre Peiffer <peifferp@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/sem.c: optimize if semops failManfred Spraul2009-12-161-2/+2
| | | | | | | | | | | | | | | | | | | Reduce the amount of scanning of the list of pending semaphore operations: If try_atomic_semop failed, then no changes were applied. Thus no need to restart. Additionally, this patch correct an incorrect comment: It's possible to wait for arbitrary semaphore values (do a dec by <x>, wait-for-zero, inc by <x> in one atomic operation) Both changes are from Nick Piggin, the patch is the result of a different split of the individual changes. Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Pierre Peiffer <peifferp@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/sem.c: sem preempt improveNick Piggin2009-12-161-15/+23
| | | | | | | | | | | | | | | | | | | | | The strange sysv semaphore wakeup scheme has a kind of busy-wait lock involved, which could deadlock if preemption is enabled during the "lock". It is an implementation detail (due to a spinlock being held) that this is actually the case. However if "spinlocks" are made preemptible, or if the sem lock is changed to a sleeping lock for example, then the wakeup would become buggy. So this might be a bugfix for -rt kernels. Imagine waker being preempted by wakee and never clearing IN_WAKEUP -- if wakee has higher RT priority then there is a priority inversion deadlock. Even if there is not a priority inversion to cause a deadlock, then there is still time wasted spinning. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Pierre Peiffer <peifferp@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/sem.c: sem use list operationsNick Piggin2009-12-161-44/+31
| | | | | | | | | | | | | | Replace the handcoded list operations in update_queue() with the standard list_for_each_entry macros. list_for_each_entry_safe() must be used, because list entries can disappear immediately uppon the wakeup event. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Pierre Peiffer <peifferp@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/sem.c: sem optimise undo list searchNick Piggin2009-12-161-6/+20
| | | | | | | | | | | | | | | | | | | Around a month ago, there was some discussion about an improvement of the sysv sem algorithm: Most (at least: some important) users only use simple semaphore operations, therefore it's worthwile to optimize this use case. This patch: Move last looked up sem_undo struct to the head of the task's undo list. Attempt to move common entries to the front of the list so search time is reduced. This reduces lookup_undo on oprofile of problematic SAP workload by 30% (see patch 4 for a description of SAP workload). Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Pierre Peiffer <peifferp@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc ns: fix memory leak (idr)Serge E. Hallyn2009-12-163-0/+3
| | | | | | | | | | | | | | | | | We have apparently had a memory leak since 7ca7e564e049d8b350ec9d958ff25eaa24226352 "ipc: store ipcs into IDRs" in 2007. The idr of which 3 exist for each ipc namespace is never freed. This patch simply frees them when the ipcns is freed. I don't believe any idr_remove() are done from rcu (and could therefore be delayed until after this idr_destroy()), so the patch should be safe. Some quick testing showed no harm, and the memory leak fixed. Caught by kmemleak. Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signals: check ->group_stop_count after tracehook_get_signal()Oleg Nesterov2009-12-161-5/+4
| | | | | | | | | | | | | Move the call to do_signal_stop() down, after tracehook call. This makes ->group_stop_count condition visible to tracers before do_signal_stop() will participate in this group-stop. Currently the patch has no effect, tracehook_get_signal() always returns 0. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signals: kill force_sig_specific()Oleg Nesterov2009-12-162-7/+0
| | | | | | | | | | Kill force_sig_specific(), this trivial wrapper has no callers. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Roland McGrath <roland@redhat.com> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signals: cosmetic, collect_signal: use SI_USEROleg Nesterov2009-12-161-1/+1
| | | | | | | | | | | | | Trivial, s/0/SI_USER/ in collect_signal() for grep. This is a bit confusing, we don't know the source of this signal. But we don't care, and "info->si_code = 0" is imho worse. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Roland McGrath <roland@redhat.com> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signals: send_signal: use si_fromuser() to detect from_ancestor_nsOleg Nesterov2009-12-161-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | Change send_signal() to use si_fromuser(). From now SEND_SIG_NOINFO triggers the "from_ancestor_ns" check. This fixes reparent_thread()->group_send_sig_info(pdeath_signal) behaviour, before this patch send_signal() does not detect the cross-namespace case when the child of the dying parent belongs to the sub-namespace. This patch can affect the behaviour of send_sig(), kill_pgrp() and kill_pid() when the caller sends the signal to the sub-namespace with "priv == 0" but surprisingly all callers seem to use them correctly, including disassociate_ctty(on_exit). Except: drivers/staging/comedi/drivers/addi-data/*.c incorrectly use send_sig(priv => 0). But his is minor and should be fixed anyway. Reported-by: Daniel Lezcano <dlezcano@fr.ibm.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Roland McGrath <roland@redhat.com> Reviewed-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* signals: SEND_SIG_NOINFO should be considered as SI_FROMUSER()Oleg Nesterov2009-12-162-8/+13
| | | | | | | | | | | | | | | | | | | | | | | No changes in compiled code. The patch adds the new helper, si_fromuser() and changes check_kill_permission() to use this helper. The real effect of this patch is that from now we "officially" consider SEND_SIG_NOINFO signal as "from user-space" signals. This is already true if we look at the code which uses SEND_SIG_NOINFO, except __send_signal() has another opinion - see the next patch. The naming of these special SEND_SIG_XXX siginfo's is really bad imho. From __send_signal()'s pov they mean SEND_SIG_NOINFO from user SEND_SIG_PRIV from kernel SEND_SIG_FORCED no info Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Roland McGrath <roland@redhat.com> Reviewed-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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