- 10 Dec, 2006 40 commits
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Avi Kivity authored
web site: http://kvm.sourceforge.net mailing list: kvm-devel@lists.sourceforge.net (http://lists.sourceforge.net/lists/listinfo/kvm-devel) The following patchset adds a driver for Intel's hardware virtualization extensions to the x86 architecture. The driver adds a character device (/dev/kvm) that exposes the virtualization capabilities to userspace. Using this driver, a process can run a virtual machine (a "guest") in a fully virtualized PC containing its own virtual hard disks, network adapters, and display. Using this driver, one can start multiple virtual machines on a host. Each virtual machine is a process on the host; a virtual cpu is a thread in that process. kill(1), nice(1), top(1) work as expected. In effect, the driver adds a third execution mode to the existing two: we now have kernel mode, user mode, and guest mode. Guest mode has its own address space mapping guest physical memory (which is accessible to user mode by mmap()ing /dev/kvm). Guest mode has no access to any I/O devices; any such access is intercepted and directed to user mode for emulation. The driver supports i386 and x86_64 hosts and guests. All combinations are allowed except x86_64 guest on i386 host. For i386 guests and hosts, both pae and non-pae paging modes are supported. SMP hosts and UP guests are supported. At the moment only Intel hardware is supported, but AMD virtualization support is being worked on. Performance currently is non-stellar due to the naive implementation of the mmu virtualization, which throws away most of the shadow page table entries every context switch. We plan to address this in two ways: - cache shadow page tables across tlb flushes - wait until AMD and Intel release processors with nested page tables Currently a virtual desktop is responsive but consumes a lot of CPU. Under Windows I tried playing pinball and watching a few flash movies; with a recent CPU one can hardly feel the virtualization. Linux/X is slower, probably due to X being in a separate process. In addition to the driver, you need a slightly modified qemu to provide I/O device emulation and the BIOS. Caveats (akpm: might no longer be true): - The Windows install currently bluescreens due to a problem with the virtual APIC. We are working on a fix. A temporary workaround is to use an existing image or install through qemu - Windows 64-bit does not work. That's also true for qemu, so it's probably a problem with the device model. [bero@arklinux.org: build fix] [simon.kagstrom@bth.se: build fix, other fixes] [uril@qumranet.com: KVM: Expose interrupt bitmap] [akpm@osdl.org: i386 build fix] [mingo@elte.hu: i386 fixes] [rdreier@cisco.com: add log levels to all printks] [randy.dunlap@oracle.com: Fix sparse NULL and C99 struct init warnings] [anthony@codemonkey.ws: KVM: AMD SVM: 32-bit host support] Signed-off-by:
Yaniv Kamay <yaniv@qumranet.com> Signed-off-by:
Avi Kivity <avi@qumranet.com> Cc: Simon Kagstrom <simon.kagstrom@bth.se> Cc: Bernhard Rosenkraenzer <bero@arklinux.org> Signed-off-by:
Uri Lublin <uril@qumranet.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by:
Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by:
Anthony Liguori <anthony@codemonkey.ws> Signed-off-by:
Andrew Morton <akpm@osdl.org> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
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Daniel Walker authored
Mostly changing alignment. Just some general cleanup. [akpm@osdl.org: build fix] Signed-off-by:
Daniel Walker <dwalker@mvista.com> Acked-by:
John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by:
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Daniel Walker authored
Simply adds some ifdefs to remove clocksoure sysfs code when CONFIG_SYSFS isn't turn on. Signed-off-by:
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Arjan van de Ven authored
This patch introduces users of the round_jiffies() function in the slab code. The slab code has a few "run every second" timers for background work; these are obviously not timing critical as long as they happen roughly at the right frequency. Signed-off-by:
Arjan van de Ven <arjan@linux.intel.com> Signed-off-by:
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Arjan van de Ven authored
This patch introduces a user: of the round_jiffies() function; the "5 second" ext3/jbd wakeup. While "every 5 seconds" doesn't sound as a problem, there can be many of these (and these timers do add up over all the kernel). The "5 second" wakeup isn't really timing sensitive; in addition even with rounding it'll still happen every 5 seconds (with the exception of the very first time, which is likely to be rounded up to somewhere closer to 6 seconds) Signed-off-by:
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Arjan van de Ven authored
Introduce a round_jiffies() function as well as a round_jiffies_relative() function. These functions round a jiffies value to the next whole second. The primary purpose of this rounding is to cause all "we don't care exactly when" timers to happen at the same jiffy. This avoids multiple timers firing within the second for no real reason; with dynamic ticks these extra timers cause wakeups from deep sleep CPU sleep states and thus waste power. The exact wakeup moment is skewed by the cpu number, to avoid all cpus from waking up at the exact same time (and hitting the same lock/cachelines there) [akpm@osdl.org: fix variable type] Signed-off-by:
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Vadim Lobanov authored
This patch provides an improved fdtable allocation scheme, useful for expanding fdtable file descriptor entries. The main focus is on the fdarray, as its memory usage grows 128 times faster than that of an fdset. The allocation algorithm sizes the fdarray in such a way that its memory usage increases in easy page-sized chunks. The overall algorithm expands the allowed size in powers of two, in order to amortize the cost of invoking vmalloc() for larger allocation sizes. Namely, the following sizes for the fdarray are considered, and the smallest that accommodates the requested fd count is chosen: pagesize / 4 pagesize / 2 pagesize <- memory allocator switch point pagesize * 2 pagesize * 4 ...etc... Unlike the current implementation, this allocation scheme does not require a loop to compute the optimal fdarray size, and can be done in efficient straightline code. Furthermore, since the fdarray overflows the pagesize boundary long before any of the fdsets do, it makes sense to optimize run-time by allocating both fdsets in a single swoop. Even together, they will still be, by far, smaller than the fdarray. The fdtable->open_fds is now used as the anchor for the fdset memory allocation. Signed-off-by:Vadim Lobanov <vlobanov@speakeasy.net> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Dipankar Sarma <dipankar@in.ibm.com> Signed-off-by:
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Vadim Lobanov authored
An fdtable can either be embedded inside a files_struct or standalone (after being expanded). When an fdtable is being discarded after all RCU references to it have expired, we must either free it directly, in the standalone case, or free the files_struct it is contained within, in the embedded case. Currently the free_files field controls this behavior, but we can get rid of it entirely, as all the necessary information is already recorded. We can distinguish embedded and standalone fdtables using max_fds, and if it is embedded we can divine the relevant files_struct using container_of(). Signed-off-by:
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Vadim Lobanov authored
Currently, each fdtable supports three dynamically-sized arrays of data: the fdarray and two fdsets. The code allows the number of fds supported by the fdarray (fdtable->max_fds) to differ from the number of fds supported by each of the fdsets (fdtable->max_fdset). In practice, it is wasteful for these two sizes to differ: whenever we hit a limit on the smaller-capacity structure, we will reallocate the entire fdtable and all the dynamic arrays within it, so any delta in the memory used by the larger-capacity structure will never be touched at all. Rather than hogging this excess, we shouldn't even allocate it in the first place, and keep the capacities of the fdarray and the fdsets equal. This patch removes fdtable->max_fdset. As an added bonus, most of the supporting code becomes simpler. Signed-off-by:
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Vadim Lobanov authored
The dup_fd() function creates a new files_struct and fdtable embedded inside that files_struct, and then possibly expands the fdtable using expand_files(). The out_release error path is invoked when expand_files() returns an error code. However, when this attempt to expand fails, the fdtable is left in its original embedded form, so it is pointless to try to free the associated fdarray and fdsets. Signed-off-by:
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Zach Brown authored
The wait_for_more_bios() function name was poorly chosen. While looking to clean it up it I noticed that the dio struct refcounting between the bio completion and dio submission paths was racey. The bio submission path was simply freeing the dio struct if atomic_dec_and_test() indicated that it dropped the final reference. The aio bio completion path was dereferencing its dio struct pointer *after dropping its reference* based on the remaining number of references. These two paths could race and result in the aio bio completion path dereferencing a freed dio, though this was not observed in the wild. This moves the refcount under the bio lock so that bio completion can drop its reference and decide to wake all in one atomic step. Once testing and waking is locked dio_await_one() can test its sleeping condition and mark itself uninterruptible under the lock. It gets simpler and wait_for_more_bios() disappears. The addition of the interrupt masking spin lock acquiry in dio_bio_submit() looks alarming. This lock acquiry existed in that path before the recent dio completion patch set. We shouldn't expect significant performance regression from returning to the behaviour that existed before the completion clean up work. This passed 4k block ext3 O_DIRECT fsx and aio-stress on an SMP machine. Signed-off-by:
Zach Brown <zach.brown@oracle.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Cc: Suparna Bhattacharya <suparna@in.ibm.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: <xfs-masters@oss.sgi.com> Signed-off-by:
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Zach Brown authored
The only time it is safe to call aio_complete() is when the ->ki_retry function returns -EIOCBQUEUED to the AIO core. direct_io_worker() has historically done this by relying on its caller to translate positive return codes into -EIOCBQUEUED for the aio case. It did this by trying to keep conditionals in sync. direct_io_worker() knew when finished_one_bio() was going to call aio_complete(). It would reverse the test and wait and free the dio in the cases it thought that finished_one_bio() wasn't going to. Not surprisingly, it ended up getting it wrong. 'ret' could be a negative errno from the submission path but it failed to communicate this to finished_one_bio(). direct_io_worker() would return < 0, it's callers wouldn't raise -EIOCBQUEUED, and aio_complete() would be called. In the future finished_one_bio()'s tests wouldn't reflect this and aio_complete() would be called for a second time which can manifest as an oops. The previous cleanups have whittled the sync and async completion paths down to the point where we can collapse them and clearly reassert the invariant that we must only call aio_complete() after returning -EIOCBQUEUED. direct_io_worker() will only return -EIOCBQUEUED when it is not the last to drop the dio refcount and the aio bio completion path will only call aio_complete() when it is the last to drop the dio refcount. direct_io_worker() can ensure that it is the last to drop the reference count by waiting for bios to drain. It does this for sync ops, of course, and for partial dio writes that must fall back to buffered and for aio ops that saw errors during submission. This means that operations that end up waiting, even if they were issued as aio ops, will not call aio_complete() from dio. Instead we return the return code of the operation and let the aio core call aio_complete(). This is purposely done to fix a bug where AIO DIO file extensions would call aio_complete() before their callers have a chance to update i_size. Now that direct_io_worker() is explicitly returning -EIOCBQUEUED its callers no longer have to translate for it. XFS needs to be careful not to free resources that will be used during AIO completion if -EIOCBQUEUED is returned. We maintain the previous behaviour of trying to write fs metadata for O_SYNC aio+dio writes. Signed-off-by:
Jeff Moyer <jmoyer@redhat.com> Cc: <xfs-masters@oss.sgi.com> Signed-off-by:
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Zach Brown authored
Now that we have a single refcount and waiting path we can reuse it in the async 'should_wait' path. It continues to rely on the fragile link between the conditional in dio_complete_aio() which decides to complete the AIO and the conditional in direct_io_worker() which decides to wait and free. By waiting before dropping the reference we stop dio_bio_end_aio() from calling dio_complete_aio() which used to wake up the waiter after seeing the reference count drop to 0. We hoist this wake up into dio_bio_end_aio() which now notices when it's left a single remaining reference that is held by the waiter. Signed-off-by:
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Zach Brown authored
Previously we had two confusing counts of bio progress. 'bio_count' was decremented as bios were processed and freed by the dio core. It was used to indicate final completion of the dio operation. 'bios_in_flight' reflected how many bios were between submit_bio() and bio->end_io. It was used by the sync path to decide when to wake up and finish completing bios and was ignored by the async path. This patch collapses the two notions into one notion of a dio reference count. bios hold a dio reference when they're between submit_bio and bio->end_io. Since bios_in_flight was only used in the sync path it is now equivalent to dio->refcount - 1 which accounts for direct_io_worker() holding a reference for the duration of the operation. dio_bio_complete() -> finished_one_bio() was called from the sync path after finding bios on the list that the bio->end_io function had deposited. finished_one_bio() can not drop the dio reference on behalf of these bios now because bio->end_io already has. The is_async test in finished_one_bio() meant that it never actually did anything other than drop the bio_count for sync callers. So we remove its refcount decrement, don't call it from dio_bio_complete(), and hoist its call up into the async dio_bio_complete() caller after an explicit refcount decrement. It is renamed dio_complete_aio() to reflect the remaining work it actually does. Signed-off-by:
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Zach Brown authored
We only need to call blk_run_address_space() once after all the bios for the direct IO op have been submitted. This removes the chance of calling blk_run_address_space() after spurious wake ups as the sync path waits for bios to drain. It's also one less difference betwen the sync and async paths. In the process we remove a redundant dio_bio_submit() that its caller had already performed. Signed-off-by:
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Zach Brown authored
There have been a lot of bugs recently due to the way direct_io_worker() tries to decide how to finish direct IO operations. In the worst examples it has failed to call aio_complete() at all (hang) or called it too many times (oops). This set of patches cleans up the completion phase with the goal of removing the complexity that lead to these bugs. We end up with one path that calculates the result of the operation after all off the bios have completed. We decide when to generate a result of the operation using that path based on the final release of a refcount on the dio structure. I tried to progress towards the final state in steps that were relatively easy to understand. Each step should compile but I only tested the final result of having all the patches applied. I've tested these on low end PC drives with aio-stress, the direct IO tests I could manage to get running in LTP, orasim, and some home-brew functional tests. In http://lkml.org/lkml/2006/9/21/103 IBM reports success with ext2 and ext3 running DIO LTP tests. They found that XFS bug which has since been addressed in the patch series. This patch: The mechanics which decide the result of a direct IO operation were duplicated in the sync and async paths. The async path didn't check page_errors which can manifest as silently returning success when the final pointer in an operation faults and its matching file region is filled with zeros. The sync path and async path differed in whether they passed errors to the caller's dio->end_io operation. The async path was passing errors to it which trips an assertion in XFS, though it is apparently harmless. This centralizes the completion phase of dio ops in one place. AIO will now return EFAULT consistently and all paths fall back to the previously sync behaviour of passing the number of bytes 'transferred' to the dio->end_io callback, regardless of errors. dio_await_completion() doesn't have to propogate EIO from non-uptodate bios now that it's being propogated through dio_complete() via dio->io_error. This lets it return void which simplifies its sole caller. Signed-off-by:
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NeilBrown authored
Fix few bugs that meant that: - superblocks weren't alway written at exactly the right time (this could show up if the array was not written to - writting to the array causes lots of superblock updates and so hides these errors). - restarting device recovery after a clean shutdown (version-1 metadata only) didn't work as intended (or at all). 1/ Ensure superblock is updated when a new device is added. 2/ Remove an inappropriate test on MD_RECOVERY_SYNC in md_do_sync. The body of this if takes one of two branches depending on whether MD_RECOVERY_SYNC is set, so testing it in the clause of the if is wrong. 3/ Flag superblock for updating after a resync/recovery finishes. 4/ If we find the neeed to restart a recovery in the middle (version-1 metadata only) make sure a full recovery (not just as guided by bitmaps) does get done. Signed-off-by:Neil Brown <neilb@suse.de> Signed-off-by:
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NeilBrown authored
Currently raid5 depends on clearing the BIO_UPTODATE flag to signal an error to higher levels. While this should be sufficient, it is safer to explicitly set the error code as well - less room for confusion. Signed-off-by:
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NeilBrown authored
There are some vestiges of old code that was used for bypassing the stripe cache on reads in raid5.c. This was never updated after the change from buffer_heads to bios, but was left as a reminder. That functionality has nowe been implemented in a completely different way, so the old code can go. Signed-off-by:
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Jeff Garzik authored
The autorun code is only used if this module is built into the static kernel image. Adjust #ifdefs accordingly. Signed-off-by:
Jeff Garzik <jeff@garzik.org> Acked-by:
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NeilBrown authored
stripe_to_pdidx finds the index of the parity disk for a given stripe. It assumes raid5 in that it uses "disks-1" to determine the number of data disks. This is incorrect for raid6 but fortunately the two usages cancel each other out. The only way that 'data_disks' affects the calculation of pd_idx in raid5_compute_sector is when it is divided into the sector number. But as that sector number is calculated by multiplying in the wrong value of 'data_disks' the division produces the right value. So it is innocuous but needs to be fixed. Also change the calculation of raid_disks in compute_blocknr to make it more obviously correct (it seems at first to always use disks-1 too). Signed-off-by:
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Raz Ben-Jehuda(caro) authored
Call the chunk_aligned_read where appropriate. Signed-off-by:
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Raz Ben-Jehuda(caro) authored
If a bypass-the-cache read fails, we simply try again through the cache. If it fails again it will trigger normal recovery precedures. update 1: From: NeilBrown <neilb@suse.de> 1/ chunk_aligned_read and retry_aligned_read assume that data_disks == raid_disks - 1 which is not true for raid6. So when an aligned read request bypasses the cache, we can get the wrong data. 2/ The cloned bio is being used-after-free in raid5_align_endio (to test BIO_UPTODATE). 3/ We forgot to add rdev->data_offset when submitting a bio for aligned-read 4/ clone_bio calls blk_recount_segments and then we change bi_bdev, so we need to invalidate the segment counts. 5/ We don't de-reference the rdev when the read completes. This means we need to record the rdev to so it is still available in the end_io routine. Fortunately bi_next in the original bio is unused at this point so we can stuff it in there. 6/ We leak a cloned bio if the target rdev is not usable. From: NeilBrown <neilb@suse.de> update 2: 1/ When aligned requests fail (read error) they need to be retried via the normal method (stripe cache). As we cannot be sure that we can process a single read in one go (we may not be able to allocate all the stripes needed) we store a bio-being-retried and a list of bioes-that-still-need-to-be-retried. When find a bio that needs to be retried, we should add it to the list, not to single-bio... 2/ We were never incrementing 'scnt' when resubmitting failed aligned requests. [akpm@osdl.org: build fix] Signed-off-by: -
Raz Ben-Jehuda(caro) authored
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Raz Ben-Jehuda(caro) authored
This will encourage read request to be on only one device, so we will often be able to bypass the cache for read requests. Signed-off-by:
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NeilBrown authored
An md array can be stopped leaving all the setting still in place, or it can torn down and destroyed. set_capacity and other change notifications only happen in the latter case, but should happen in both. Signed-off-by:
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Paul Mackerras authored
This is an fbdev driver for the IBM GXT4500P display card found in some IBM System P (pSeries) machines. These cards have hardware 2D and 3D capabilities, but the driver does not use them; it just exports a dumb framebuffer. Signed-off-by:
Paul Mackerras <paulus@samba.org> Acked-by:
James Simmons <jsimmons@infradead.org> Cc: "Antonino A. Daplas" <adaplas@pol.net> Signed-off-by:
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Alan Cox authored
The ESB2 appears to emit spurious DMA interrupts when configured for native mode and handling ATAPI devices. Stratus were able to pin this bug down and produce a patch. This is a rework which applies the fixup only to the ESB2 (for now). We can apply it to other chips later if the same problem is found. This code has been tested and confirmed to fix the problem on the tested systems. Signed-off-by:
Alan Cox <alan@redhat.com> (Most of the hard work done by Stratus however) Cc: Jens Axboe <axboe@suse.de> Signed-off-by:
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Miguel Ojeda Sandonis authored
[akpm@osdl.org: additional cleanups] Signed-off-by:
Miguel Ojeda Sandonis <maxextreme@gmail.com> Acked-by:
Ingo Molnar <mingo@elte.hu> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by:
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Chen, Kenneth W authored
RT task does not participate in interactiveness priority and thus shouldn't be bothered with timestamp and p->sleep_type manipulation when task is being put on run queue. Bypass all of the them with a single if (rt_task) test. Signed-off-by:
Ken Chen <kenneth.w.chen@intel.com> Acked-by:
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Chen, Kenneth W authored
Remove scheduler stats lb_stopbalance counter. This counter can be calculated by: lb_balanced - lb_nobusyg - lb_nobusyq. There is no need to create gazillion counters while we can derive the value. Signed-off-by:
Suresh Siddha <suresh.b.siddha@intel.com> Acked-by:
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Siddha, Suresh B authored
Currently at a particular domain, each cpu in the sched group will do a load balance at the frequency of balance_interval. More the cores and threads, more the cpus will be in each sched group at SMP and NUMA domain. And we endup spending quite a bit of time doing load balancing in those domains. Fix this by making only one cpu(first idle cpu or first cpu in the group if all the cpus are busy) in the sched group do the load balance at that particular sched domain and this load will slowly percolate down to the other cpus with in that group(when they do load balancing at lower domains). Signed-off-by:
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Mike Galbraith authored
Co-opt rq->timestamp_last_tick to maintain a cache_hot_time evaluation reference timestamp at both tick and sched times to prevent said reference, formerly rq->timestamp_last_tick, from being behind task->last_ran at evaluation time, and to move said reference closer to current time on the remote processor, intent being to improve cache hot evaluation and timestamp adjustment accuracy for task migration. Fix minor sched_time double accounting error which occurs when a task passing through schedule() does not schedule off, and takes the next timer tick. [kenneth.w.chen@intel.com: cleanup] Signed-off-by:
Mike Galbraith <efault@gmx.de> Acked-by:
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Christoph Lameter authored
Large sched domains can be very expensive to scan. Add an option SD_SERIALIZE to the sched domain flags. If that flag is set then we make sure that no other such domain is being balanced. [akpm@osdl.org: build fix] Signed-off-by:
Christoph Lameter <clameter@sgi.com> Cc: Peter Williams <pwil3058@bigpond.net.au> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <clameter@sgi.com> Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com> Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com> Acked-by:
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Christoph Lameter authored
Trigger softirq less frequently We trigger the softirq before this patch using offset of sd->interval. However, if the queue is busy then it is sufficient to schedule the softirq with sd->interval * busy_factor. So we modify the calculation of the next time to balance by taking the interval added to last_balance again. This is only the right value if the idle/busy situation continues as is. There are two potential trouble spots: - If the queue was idle and now gets busy then we call rebalance early. However, that is not a problem because we will then use the longer interval for the next period. - If the queue was busy and becomes idle then we potentially wait too long before rebalancing. However, when the task goes idle then idle_balance is called. We add another calculation of the next balance time based on sd->interval in idle_balance so that we will rebalance soon. V2->V3: - Calculate rebalance time based on current jiffies and not based on the jiffies at the last time we load balanced. We no longer rely on staggering and therefore we can affort to do this now. V3->V4: - Use functions to do jiffy comparisons. Signed-off-by:
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Christoph Lameter authored
Call rebalance_tick (renamed to run_rebalance_domains) from a newly introduced softirq. We calculate the earliest time for each layer of sched domains to be rescanned (this is the rescan time for idle) and use the earliest of those to schedule the softirq via a new field "next_balance" added to struct rq. Signed-off-by:
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Christoph Lameter authored
Perform the idle state determination in rebalance_tick. If we separate balancing from sched_tick then we also need to determine the idle state in rebalance_tick. V2->V3 Remove useless idlle != 0 check. Checking nr_running seems to be sufficient. Thanks Suresh. Signed-off-by:
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Christoph Lameter authored
A load calculation is always done in rebalance_tick() in addition to the real load balancing activities that only take place when certain jiffie counts have been reached. Move that processing into a separate function and call it directly from scheduler_tick(). Also extract the time slice handling from scheduler_tick and put it into a separate function. Then we can clean up scheduler_tick significantly. It will no longer have any gotos. Signed-off-by:
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Christoph Lameter authored
Interrupts must be disabled for request queue locks if we want to run load_balance() with interrupts enabled. Signed-off-by:
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Christoph Lameter authored
Timer interrupts already are staggered. We do not need an additional layer of time staggering for short load balancing actions that take a reasonably small portion of the time slice. For load balancing on large sched_domains we will add a serialization later that avoids concurrent load balance operations and thus has the same effect as load staggering. Signed-off-by:
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