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2009-12-16bitmap: introduce bitmap_set, bitmap_clear, bitmap_find_next_zero_areaAkinobu Mita
This introduces new bitmap functions: bitmap_set: Set specified bit area bitmap_clear: Clear specified bit area bitmap_find_next_zero_area: Find free bit area These are mostly stolen from iommu helper. The differences are: - Use find_next_bit instead of doing test_bit for each bit - Rewrite bitmap_set and bitmap_clear Instead of setting or clearing for each bit. - Check the last bit of the limit iommu-helper doesn't want to find such area - The return value if there is no zero area find_next_zero_area in iommu helper: returns -1 bitmap_find_next_zero_area: return >= bitmap size Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: "David S. Miller" <davem@davemloft.net> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Lothar Wassmann <LW@KARO-electronics.de> Cc: Roland Dreier <rolandd@cisco.com> Cc: Yevgeny Petrilin <yevgenyp@mellanox.co.il> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16qnx4: use hweight8Akinobu Mita
Use hweight8 instead of counting for each bit Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Acked-by: Anders Larsen <al@alarsen.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16qnx4fs: remove remains of the (defunct) write supportAnders Larsen
commit 945ffe54bbd56ceed62de3b908800fd7c6ffb284 ("qnx4: remove write support") removed the (defunct) write support but missed a chunk of related, dead code. Signed-off-by: Anders Larsen <al@alarsen.net> Cc: Jiri Kosina <jkosina@suse.cz> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16resource: constify arg to resource_size() and resource_type()Jean Delvare
resource_size() doesn't change the resource it operates on, so the res parameter can be marked const. Same for resource_type(). Signed-off-by: Jean Delvare <khali@linux-fr.org> Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16gru: send cross partition interrupts using the gruJack Steiner
GRU Message queue instructions are used to deliver messages to other SSIs within the numalink domain. In most cases, a single GRU mesq instruction will deliver both the message AND an interrupt to notify the other SSI that a messsage is present. In some cases, however, the interrupt must be sent explicitly. To improve resilency, the GRU driver should send these explicit interrupts using the GRU to write the remote chipset register. Current code sends the interrupt using a cpu instruction to write the chipset register. 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>
2009-12-16gru: function to generate chipset IPI valuesJack Steiner
Create a function to generate the value that is written to the UV hub MMR to cause an IPI interrupt to be sent. The function will be used in the GRU message queue error recovery code that sends IPIs to nodes in remote partitions. 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>
2009-12-16gru: update driver version numberJack Steiner
Update the version number of the GRU driver. 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>
2009-12-16gru: improve GRU TLB dropin statisticsJack Steiner
Update the TLB dropin statistics kept for each GRU context. Count TLB dropins separate from the misses - some misses do not result in a TLB dropin. Some of the diagnostics need both counts. 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>
2009-12-16gru: fix GRU interrupt race at deallocateJack Steiner
Fix a race where an interrupt could be received for a GRU context that has been deallocated. 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>
2009-12-16gru: add hugepage supportJack Steiner
Add support for hugepages. Easier than I originally thought. 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>
2009-12-16gru: fix bug in allocation of kernel contextsJack Steiner
Fix a bug in the assignment of GRU contexts used for kernel functions. If a sleep occurs on the wait for a semaphore, the thread could switch cpus and allocate resources on the wrong blade. 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>
2009-12-16gru: update GRU structures to match latest hardware specJack Steiner
Add a few new definitions for chipset MMR field names. This matches rev 0.7 of the hardware spec. 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>
2009-12-16gru: check for correct GRU chiplet assignmentJack Steiner
Simplify the code that checks for correct assignment of GRU contexts to 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>
2009-12-16gru: remove stray local_irq_enableJack Steiner
Remove a stray local_irq_enable() in the GRU TLB dropin code. 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>
2009-12-16gru: add symbolic names for GRU error codeJack Steiner
Use symbol names instead of numbers for error return values for the vtop functions. 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>
2009-12-16gru: fix bug in exception handlingJack Steiner
Fix a GRU driver bug converting a CBR address to the context that contains the CBR. The conversion is rarely done so performance does not matter. 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>
2009-12-16gru: preload tlb for bcopy instructionsJack Steiner
Add anticipatory TLB dropins for GRU TLB misses that occur on BCOPY instructions that copy large amounts of data. 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>
2009-12-16gru: expicitly set instruction status to activeJack Steiner
Explicitly set GRU instructions to "ACTIVE". This eliminates the need for barriers that would have been necessary to prevent reading the instruction "status" field before the GRU had actually started the instruction. 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>
2009-12-16gru: add additional GRU statisticsJack Steiner
Add additional GRU statistics & debug messages. 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>
2009-12-16gru: update irq infrastructureJack Steiner
Update the GRU irq allocate/free functions to use the latest upstream infrastructure. 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>
2009-12-16gru: fix prefetch and speculation bugsJack Steiner
Fix several bugs related to prefetch, ordering & speculation: - GRU cch_allocate() instruction causes cacheable memory to be created. Add a barriers to prevent speculation from prefetching data before it exists. - Add memory barriers before cache-flush instructions to ensure that previously stored data is included in the line flushed to memory. 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>
2009-12-16gru: check for valid vmaJack Steiner
Fix bug caused by failure to allocate a GRU gts structure. The old code failed to handle the case where the vma was invalid. 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>
2009-12-16gru: add test for gru_copy_gpaJack Steiner
Improve existing driver self-tests. Add a new debugging test to the SGI GRU driver for verifying the global GRU copy function. 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>
2009-12-16gru: add debug option for cache flushingJack Steiner
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>
2009-12-16gru: handle failures to mmu_notifier_registerJack Steiner
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>
2009-12-16gru: support 64-bit GRU addressesJack Steiner
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>
2009-12-16gru: improve messages for malfunctioning GRUsJack Steiner
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>
2009-12-16gru: fix bug in module unloadJack Steiner
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>
2009-12-16gru: allow users to specify gru chiplet 3Jack Steiner
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>
2009-12-16gru: allow users to specify gru chiplet 2Jack Steiner
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>
2009-12-16gru: allow users to specify gru chiplet 1Jack Steiner
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>
2009-12-16gru: handle blades without memoryJack Steiner
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>
2009-12-16gru: fix istatus race in GRU tlb dropinJack Steiner
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>
2009-12-16gru: add comments raised in previous code reviewsJack Steiner
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>
2009-12-16gru: initial GRU based on blade topologyJack Steiner
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>
2009-12-16UV - XPC: pass nasid instead of nid to gru_create_message_queueRobin Holt
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>
2009-12-16x86: uv: XPC receive message reuse triggers invalid BUG_ON()Robin Holt
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>
2009-12-16X86: uv: xpc_make_first_contact hang due to not accepting ACTIVE stateRobin Holt
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>
2009-12-16x86: uv: xpc NULL deref when mesq becomes emptyRobin Holt
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>
2009-12-16x86: uv: update XPC to handle updated BIOS interfaceRobin Holt
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>
2009-12-16X86: uv: implement a gru_read_gpa kernel functionRobin Holt
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>
2009-12-16x86: uv: introduce uv_gpa_is_mmrRobin Holt
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>
2009-12-16x86: uv: xpc needs to provide an abstraction for uv_gpaRobin Holt
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>
2009-12-16x86: uv: introduce a means to translate from gpa -> socket_paddrRobin Holt
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>
2009-12-16direct-io: cleanup blockdev_direct_IO lockingChristoph Hellwig
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>
2009-12-16dio: don't zero out the pages array inside struct dioJeff Moyer
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>
2009-12-16aio: remove unused fieldShaohua Li
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>
2009-12-16FS-Cache: Avoid maybe-used-uninitialised warning on variableDavid Howells
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>
2009-12-16kexec: premit reduction of the reserved memory sizeAmerigo Wang
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>
2009-12-16parport_pc.c: use correct length in strncmpJoe Perches
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>