machines which can clearly afford the memory.
This is a somewhat conservative version of the patch - more fine tuning may be
necessary.
Idea from: Thread on hackers@
Discussed with: alc
most one call to pmap_qremove(), and thus one TLB shootdown, instead of one
call and TLB shootdown per page.
Simplify the interface to vm_hold_free_pages().
MFC after: 3 weeks
the maintenance of vm_pageout_deficit can be localized to just two places:
vm_page_alloc() and vm_pageout_scan().
This change also corrects an off-by-one error in the maintenance of
vm_pageout_deficit. Historically, the buffer cache functions, allocbuf()
and vm_hold_load_pages(), have not taken into account that vm_page_alloc()
already increments vm_pageout_deficit by one.
Reviewed by: kib
specify the increment of vm_pageout_deficit when sleeping due to page
shortage. Then, in allocbuf(), the code to allocate pages when extending
vmio buffer can be replaced by a call to vm_page_grab().
Suggested and reviewed by: alc
MFC after: 2 weeks
one or more mappings to the bogus page must be replaced, call pmap_qenter()
just once. Previously, pmap_qenter() was called for each mapping to the
bogus page.
MFC after: 3 weeks
per-buf flag to catch if a buf is double-counted in the free count.
This code was useful to debug an instance where a local patch at Isilon
was incorrectly managing numfreebufs for a new buf state.
Reviewed by: jeff
Approved by: zml (mentor)
from the buffer pages to buffer. Combine the code to set buffer
dirty range (previously in vfs_setdirty()) and to clean the pages
(vfs_clean_pages()) into new function vfs_clean_pages_dirty_buf(). Now
the vm object lock is acquired only once.
Drain the VPO_BUSY bit of the buffer pages before setting valid
and clean bits in vfs_clean_pages_dirty_buf() with new helper
vfs_drain_busy_pages(). pmap_clear_modify() asserts that page is not
busy.
In vfs_busy_pages(), move the wait for draining of VPO_BUSY before
the dirtyness handling, to follow the structure of
vfs_clean_pages_dirty_buf().
Reported and tested by: pho
Suggested and reviewed by: alc
MFC after: 2 weeks
independent code. Move this code into mincore(), and eliminate the
page queues lock from pmap_mincore().
Push down the page queues lock into pmap_clear_modify(),
pmap_clear_reference(), and pmap_is_modified(). Assert that these
functions are never passed an unmanaged page.
Eliminate an inaccurate comment from powerpc/powerpc/mmu_if.m:
Contrary to what the comment says, pmap_mincore() is not simply an
optimization. Without a complete pmap_mincore() implementation,
mincore() cannot return either MINCORE_MODIFIED or MINCORE_REFERENCED
because only the pmap can provide this information.
Eliminate the page queues lock from vfs_setdirty_locked_object(),
vm_pageout_clean(), vm_object_page_collect_flush(), and
vm_object_page_clean(). Generally speaking, these are all accesses
to the page's dirty field, which are synchronized by the containing
vm object's lock.
Reduce the scope of the page queues lock in vm_object_madvise() and
vm_page_dontneed().
Reviewed by: kib (an earlier version)
eliminate it.
Assert that the object containing the page is locked in
vm_page_test_dirty(). Perform some style clean up while I'm here.
Reviewed by: kib
vm_page_try_to_free(). Consequently, push down the page queues lock into
pmap_enter_quick(), pmap_page_wired_mapped(), pmap_remove_all(), and
pmap_remove_write().
Push down the page queues lock into Xen's pmap_page_is_mapped(). (I
overlooked the Xen pmap in r207702.)
Switch to a per-processor counter for the total number of pages cached.
to unconditionally set PG_REFERENCED on a page before sleeping. In many
cases, it's perfectly ok for the page to disappear, i.e., be reclaimed by
the page daemon, before the caller to vm_page_sleep() is reawakened.
Instead, we now explicitly set PG_REFERENCED in those cases where having
the page persist until the caller is awakened is clearly desirable. Note,
however, that setting PG_REFERENCED on the page is still only a hint,
and not a guarantee that the page should persist.
architecture from page queue lock to a hashed array of page locks
(based on a patch by Jeff Roberson), I've implemented page lock
support in the MI code and have only moved vm_page's hold_count
out from under page queue mutex to page lock. This changes
pmap_extract_and_hold on all pmaps.
Supported by: Bitgravity Inc.
Discussed with: alc, jeffr, and kib
brings in support for an optional intent log which eliminates the need
for background fsck on unclean shutdown.
Sponsored by: iXsystems, Yahoo!, and Juniper.
With help from: McKusick and Peter Holm
In r205860 I missed the fact that there is code that strongly assumes
that devvp bo_bsize is equal to underlying provider's sectorsize.
In those places it is hard to obtain the sectorsize in an alternative
way if devvp bo_bsize is set to something else.
So, I am reverting bo_bsize assigment in g_vfs_open.
Instead, in getblk I use DEV_BSIZE block size for b_offset calculation
if vp is a disk vp as reported by vn_isdisk. This should coinside with
vp being a devvp.
Reported by: Mykola Dzham <i@levsha.me>
Tested by: Mykola Dzham <i@levsha.me>
Pointyhat to: avg
MFC after: 2 weeks
X-ToDo: convert bread(devvp) in all fs to use bo_bsize-d blocks
portion of the page that was written. Among other problems, this
page might be picked up by pagedaemon, with failed assertion in
vm_pageout_flush() about validity of the page.
Reported and tested by: pho
Approved by: re (kensmith)
MFC after: 3 weeks
Add support for kernel fault injection using KFAIL_POINT_* macros and
fail_point_* infrastructure. Add example fail point in vfs_bio.c to
simulate VM buf pressure.
Approved by: dfr (mentor)
Provide a more descriptive comment.
Eliminate dead code. The page cannot possibly have PG_ZERO set.
Eliminate unnecessary blank lines.
Reviewed by: tegge
following changes:
Rename vfs_page_set_valid() to vfs_page_set_validclean() to reflect
what this function actually does. Suggested by: tegge
Introduce a new version of vfs_page_set_valid() that does no more than
what the function's name implies. Specifically, it does not update
the page's dirty mask, and thus it does not require the page queues
lock to be held.
Update two of the three callers to the old vfs_page_set_valid() to
call vfs_page_set_validclean() instead because they actually require
the page's dirty mask to be cleared.
Introduce vm_page_set_valid().
Reviewed by: tegge
suffer from the race condition that motivated revision 1.94. Consequently,
the work-around that was implemented by revision 1.94 is no longer needed.
Moreover, reverting this work-around eliminates the need for
vfs_busy_pages() to acquire the page queues lock when preparing a buffer
for read.
Reviewed by: tegge
B_DELWRI cleanup and vnode disassociation should happen just before to
assign the buffer to a queue.
Reported by: miwi, Volker <volker at vwsoft dot com>,
Ben Kaduk <minimarmot at gmail dot com>,
Christopher Mallon <christoph dot mallon at gmx dot de>
Tested by: lulf, miwi
the "nbufkv" sleep.
First, ffs background cg group block write requests a new buffer for
the shadow copy. When ffs_bufwrite() is called from the bufdaemon due
to buffers shortage, requesting the buffer deadlock bufdaemon.
Introduce a new flag for getnewbuf(), GB_NOWAIT_BD, to request getblk
to not block while allocating the buffer, and return failure
instead. Add a flag argument to the geteblk to allow to pass the flags
to getblk(). Do not repeat the getnewbuf() call from geteblk if buffer
allocation failed and either GB_NOWAIT_BD is specified, or geteblk()
is called from bufdaemon (or its helper, see below). In
ffs_bufwrite(), fall back to synchronous cg block write if shadow
block allocation failed.
Since r107847, buffer write assumes that vnode owning the buffer is
locked. The second problem is that buffer cache may accumulate many
buffers belonging to limited number of vnodes. With such workload,
quite often threads that own the mentioned vnodes locks are trying to
read another block from the vnodes, and, due to buffer cache
exhaustion, are asking bufdaemon for help. Bufdaemon is unable to make
any substantial progress because the vnodes are locked.
Allow the threads owning vnode locks to help the bufdaemon by doing
the flush pass over the buffer cache before getnewbuf() is going to
uninterruptible sleep. Move the flushing code from buf_daemon() to new
helper function buf_do_flush(), that is called from getnewbuf(). The
number of buffers flushed by single call to buf_do_flush() from
getnewbuf() is limited by new sysctl vfs.flushbufqtarget. Prevent
recursive calls to buf_do_flush() by marking the bufdaemon and threads
that temporarily help bufdaemon by TDP_BUFNEED flag.
In collaboration with: pho
Reviewed by: tegge (previous version)
Tested by: glebius, yandex ...
MFC after: 3 weeks
address space sizes to be longs instead of ints. Specifically, the follow
values are now longs: runningbufspace, bufspace, maxbufspace,
bufmallocspace, maxbufmallocspace, lobufspace, hibufspace, lorunningspace,
hirunningspace, maxswzone, maxbcache, and maxpipekva. Previously, a
relatively small number (~ 44000) of buffers set in kern.nbuf would result
in integer overflows resulting either in hangs or bogus values of
hidirtybuffers and lodirtybuffers. Now one has to overflow a long to see
such problems. There was a check for a nbuf setting that would cause
overflows in the auto-tuning of nbuf. I've changed it to always check and
cap nbuf but warn if a user-supplied tunable would cause overflow.
Note that this changes the ABI of several sysctls that are used by things
like top(1), etc., so any MFC would probably require a some gross shims
to allow for that.
MFC after: 1 month
- Align the fifo output in fifo_print() with other vn_printf() output.
- Remove the leading space from lockmgr_printinfo() so its output lines up
in vn_printf().
- lockmgr_printinfo() now ends with a newline, so remove an extra newline
from vn_printf().
In particular following functions KPI results modified:
- bufobj_invalbuf()
- bufsync()
and BO_SYNC() "virtual method" of the buffer objects set.
Main consumers of bufobj functions are affected by this change too and,
in particular, functions which changed their KPI are:
- vinvalbuf()
- g_vfs_close()
Due to the KPI breakage, __FreeBSD_version will be bumped in a later
commit.
As a side note, please consider just temporary the 'curthread' argument
passing to VOP_SYNC() (in bufsync()) as it will be axed out ASAP
Reviewed by: kib
Tested by: Giovanni Trematerra <giovanni dot trematerra at gmail dot com>
Show the b_dep value for the buffer in the show buffer command.
Add a comand to dump the dirty/clean buffer list for vnode.
Reviewed by: tegge
Tested and used by: pho
MFC after: 1 month
dropped after the call to lockmgr() so just revert this approach using
something similar to the precedent one:
BUF_LOCKWAITERS() just checks if there are waiters (not the actual number
of them) and it is based on newly introduced lockmgr_waiters() which
returns if the lockmgr has waiters or not. The name has been choosen
differently by old lockwaiters() in order to not confuse them.
KPI results enriched by this commit so __FreeBSD_version bumping and
manpage update will be happening soon.
'struct buf' also changes, so kernel ABI is disturbed.
Bug found by: jeff
Approved by: jeff, kib
BO_LOCK/UNLOCK/MTX when manipulating the bufobj.
- Create a new lock in the bufobj to lock bufobj fields independently.
This leaves the vnode interlock as an 'identity' lock while the bufobj
is an io lock. The bufobj lock is ordered before the vnode interlock
and also before the mnt ilock.
- Exploit this new lock order to simplify softdep_check_suspend().
- A few sync related functions are marked with a new XXX to note that
we may not properly interlock against a non-zero bv_cnt when
attempting to sync all vnodes on a mountlist. I do not believe this
race is important. If I'm wrong this will make these locations easier
to find.
Reviewed by: kib (earlier diff)
Tested by: kris, pho (earlier diff)
