src/sys/dev/md, branch releng/10.2

MFC r269190:

2014-08-04T01:14:27Z

For md(4), posix shm(3) and tmpfs(5), free swap space used by paged in dirty page, which is written by the process.

MFC Alexander Motin's GEOM direct dispatch work:

2014-01-07T01:32:23Z

r256603: Introduce new function devstat_end_transaction_bio_bt(), adding new argument to specify present time. Use this function to move binuptime() out of lock, substantially reducing lock congestion when slow timecounter is used. r256606: Move g_io_deliver() out of the lock, as required for direct dispatch. Move g_destroy_bio() out too to reduce lock scope even more. r256607: Fix passing uninitialized bio_resid argument to g_trace(). r256610: Add unmapped I/O support to GEOM RAID. r256830: Restore BIO_UNMAPPED and BIO_TRANSIENT_MAPPING in biodonne() when unmapping temporary mapped buffer. That fixes double unmap if biodone() called twice for the same BIO (but with different done methods). r256880: Merge GEOM direct dispatch changes from the projects/camlock branch. When safety requirements are met, it allows to avoid passing I/O requests to GEOM g_up/g_down thread, executing them directly in the caller context. That allows to avoid CPU bottlenecks in g_up/g_down threads, plus avoid several context switches per I/O. r259247: Fix bug introduced at r256607. We have to recalculate bp_resid here since sizes of original and completed requests may differ due to end of media. Testing of the stable/10 merge was done by Netflix, but all of the credit goes to Alexander and iX Systems. Submitted by: mav Sponsored by: iX Systems

Give the page allocations initiated by the swap-backed md(4) a higher

2013-08-30T20:12:23Z

priority. If the write is requested by a system daemon, sleeping there would starve resources and cause deadlock. Reported and tested by: pho Sponsored by: The FreeBSD Foundation

Remove the deprecated VM_ALLOC_RETRY flag for the vm_page_grab(9).

2013-08-22T07:39:53Z

The flag was mandatory since r209792, where vm_page_grab(9) was changed to only support the alloc retry semantic. Suggested and reviewed by: alc Sponsored by: The FreeBSD Foundation

The soft and hard busy mechanism rely on the vm object lock to work.

2013-08-09T11:11:11Z

Unify the 2 concept into a real, minimal, sxlock where the shared acquisition represent the soft busy and the exclusive acquisition represent the hard busy. The old VPO_WANTED mechanism becames the hard-path for this new lock and it becomes per-page rather than per-object. The vm_object lock becames an interlock for this functionality: it can be held in both read or write mode. However, if the vm_object lock is held in read mode while acquiring or releasing the busy state, the thread owner cannot make any assumption on the busy state unless it is also busying it. Also: - Add a new flag to directly shared busy pages while vm_page_alloc and vm_page_grab are being executed. This will be very helpful once these functions happen under a read object lock. - Move the swapping sleep into its own per-object flag The KPI is heavilly changed this is why the version is bumped. It is very likely that some VM ports users will need to change their own code. Sponsored by: EMC / Isilon storage division Discussed with: alc Reviewed by: jeff, kib Tested by: gavin, bapt (older version) Tested by: pho, scottl

Fix the data corruption on the swap-backed md.

2013-05-24T09:48:42Z

Assign the rv variable a success code if the pager was not asked for the page. Using an error code from the previous processed page caused zeroing of the valid page, when e.g. the previous page was not available in the pager. Reported by: lstewart Sponsored by: The FreeBSD Foundation MFC after: 1 week

Do not declare that preloaded md(4) supports unmapped bio requests, it

2013-04-02T19:39:31Z

does not. Reported by: Sponsored by: The FreeBSD Foundation

Support unmapped i/o for the md(4).

2013-03-19T14:53:23Z

The vnode-backed md(4) has to map the unmapped bio because VOP_READ() and VOP_WRITE() interfaces do not allow to pass unmapped requests to the filesystem. Vnode-backed md(4) uses pbufs instead of relying on the bio_transient_map, to avoid usual md deadlock. Sponsored by: The FreeBSD Foundation Tested by: pho, scottl

Switch the vm_object mutex to be a rwlock. This will enable in the

2013-03-09T02:32:23Z

future further optimizations where the vm_object lock will be held in read mode most of the time the page cache resident pool of pages are accessed for reading purposes. The change is mostly mechanical but few notes are reported: * The KPI changes as follow: - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK() - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK() - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK() - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED() (in order to avoid visibility of implementation details) - The read-mode operations are added: VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(), VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED() * The vm/vm_pager.h namespace pollution avoidance (forcing requiring sys/mutex.h in consumers directly to cater its inlining functions using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h consumers now must include also sys/rwlock.h. * zfs requires a quite convoluted fix to include FreeBSD rwlocks into the compat layer because the name clash between FreeBSD and solaris versions must be avoided. At this purpose zfs redefines the vm_object locking functions directly, isolating the FreeBSD components in specific compat stubs. The KPI results heavilly broken by this commit. Thirdy part ports must be updated accordingly (I can think off-hand of VirtualBox, for example). Sponsored by: EMC / Isilon storage division Reviewed by: jeff Reviewed by: pjd (ZFS specific review) Discussed with: alc Tested by: pho

Print correct unit number when attaching preloaded memory disks.

2012-11-21T17:05:57Z

Retire now unused mdunits variable.