This eliminates the staircase of conditions in vm_map_entry_set_vnode_text().
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D30070
specialized for swap and vnode pagers, and used to implement
vm_object_set_writeable_dirty().
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D30070
Replace MAXPHYS by runtime variable maxphys. It is initialized from
MAXPHYS by default, but can be also adjusted with the tunable kern.maxphys.
Make b_pages[] array in struct buf flexible. Size b_pages[] for buffer
cache buffers exactly to atop(maxbcachebuf) (currently it is sized to
atop(MAXPHYS)), and b_pages[] for pbufs is sized to atop(maxphys) + 1.
The +1 for pbufs allow several pbuf consumers, among them vmapbuf(),
to use unaligned buffers still sized to maxphys, esp. when such
buffers come from userspace (*). Overall, we save significant amount
of otherwise wasted memory in b_pages[] for buffer cache buffers,
while bumping MAXPHYS to desired high value.
Eliminate all direct uses of the MAXPHYS constant in kernel and driver
sources, except a place which initialize maxphys. Some random (and
arguably weird) uses of MAXPHYS, e.g. in linuxolator, are converted
straight. Some drivers, which use MAXPHYS to size embeded structures,
get private MAXPHYS-like constant; their convertion is out of scope
for this work.
Changes to cam/, dev/ahci, dev/ata, dev/mpr, dev/mpt, dev/mvs,
dev/siis, where either submitted by, or based on changes by mav.
Suggested by: mav (*)
Reviewed by: imp, mav, imp, mckusick, scottl (intermediate versions)
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D27225
vm_ooffset_t is now unsigned. Remove some tests for negative values,
or make other adjustments accordingly.
Reported by: Coverity
Reviewed by: kib markj
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D26214
This will be used later, where it matters on 32bit arches.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D25968
Finish updating comments to reflect new locking protocols introduced
over the past year. In particular, vm_page_lock is now effectively
unused.
Reviewed by: kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D25868
Rather than marking the read ahead/behind pages valid even though they were
not initialized, free them using the new function vm_page_free_invalid().
Reviewed by: markj, kib
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D25430
Instead, just skip marking pages valid if the read fails. Future
attempts to access such pages will notice that they are not marked valid
and try to read them from disk again.
Reviewed by: kib, markj
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D25138
Don't convert all lower layer errors to EIO. Instead, pass the actual error up
the stack. This will allow the upper layers that look for ENXIO to react
properly to that signal from the lower layers and, for UFS, unmount the
filesystem.
Reviewed by: kib@
Differential Revision: https://reviews.freebsd.org/D23755
There's no need to spam the console with this error message. If there's an I/O
error, the disk/cam driver will report it at the lower levels. If that's an
actual problem, the upper layers will report that.
Reviewed by: kib@
Differential Revision: https://reviews.freebsd.org/D23756
The vnode pager does not want the object lock held. Moving this out allows
further object lock scope reduction in callers. While here add some missing
paging in progress calls and an assert. The object handle is now protected
explicitly with pip.
Reviewed by: kib, markj
Differential Revision: https://reviews.freebsd.org/D23033
Filesystems which want to use it in limited capacity can employ the
VOP_UNLOCK_FLAGS macro.
Reviewed by: kib (previous version)
Differential Revision: https://reviews.freebsd.org/D21427
The current vnode layout is not smp-friendly by having frequently read data
avoidably sharing cachelines with very frequently modified fields. In
particular v_iflag inspected for VI_DOOMED can be found in the same line with
v_usecount. Instead make it available in the same cacheline as the v_op, v_data
and v_type which all get read all the time.
v_type is avoidably 4 bytes while the necessary data will easily fit in 1.
Shrinking it frees up 3 bytes, 2 of which get used here to introduce a new
flag field with a new value: VIRF_DOOMED.
Reviewed by: kib, jeff
Differential Revision: https://reviews.freebsd.org/D22715
omit the object lock if we are above a certain threshold. Hold only a
single vnode reference when the vnode object has any ref > 0. This
allows us to only lock the object and vnode on 0-1 and 1-0 transitions.
Differential Revision: https://reviews.freebsd.org/D22452
Certain consumers still need to guarantee a stable reference so we can not
switch entirely to atomics yet. Exclusive lock holders can still modify
and examine the refcount without using the ref api.
Reviewed by: kib
Tested by: pho
Sponsored by: Netflix, Intel
Differential Revision: https://reviews.freebsd.org/D21598
We now assert that a page is busy when updating its validity-tracking
state, but bogus_page is not busied during a getpages operation.
Reported by: syzkaller
Reviewed by: alc, kib
Discussed with: jeff
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D22124
except for filesystems that set the MNTK_VMSETSIZE_BUG, Set the flag for ZFS.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D21883
The flag specifies that vm_fault() handler should check the vnode'
vm_object size under the vnode lock. It is converted into the object'
OBJ_SIZEVNLOCK flag in vnode_pager_alloc().
Tested by: pho
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D21883
Atomics are used for page busy and valid state when the shared busy is
held. The details of the locking protocol and valid and dirty
synchronization are in the updated vm_page.h comments.
Reviewed by: kib, markj
Tested by: pho
Sponsored by: Netflix, Intel
Differential Revision: https://reviews.freebsd.org/D21594
Currently writemapping accounting is only done for vnode_pager which does
some accounting on the underlying vnode.
Extend this to allow accounting to be possible for any of the pager types.
New pageops are added to update/release writecount that need to be
implemented for any pager wishing to do said accounting, and we implement
these methods now for both vnode_pager (unchanged) and swap_pager.
The primary motivation for this is to allow other systems with OBJT_SWAP
objects to check if their objects have any write mappings and reject
operations with EBUSY if so. posixshm will be the first to do so in order to
reject adding write seals to the shmfd if any writable mappings exist.
Reviewed by: kib, markj
Differential Revision: https://reviews.freebsd.org/D21456
Current implementation of vnode_create_vobject() and
vnode_destroy_vobject() is written so that it prepared to handle the
vm object destruction for live vnode. Practically, no filesystems use
this, except for some remnants that were present in UFS till today.
One of the consequences of that model is that each filesystem must
call vnode_destroy_vobject() in VOP_RECLAIM() or earlier, as result
all of them get rid of the v_object in reclaim.
Move the call to vnode_destroy_vobject() to vgonel() before
VOP_RECLAIM(). This makes v_object stable: either the object is NULL,
or it is valid vm object till the vnode reclamation. Remove code from
vnode_create_vobject() to handle races with the parallel destruction.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D21412
VM_OBJECT_DROP/VM_OBJECT_PICKUP to handle functions that are called with
uncertain lock state.
Reviewed by: kib, markj
Tested by: pho
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D21310
Similar to r348026, exhaustive search for uses of CTRn() and cross reference
ktr.h includes. Where it was obvious that an OS compat header of some kind
included ktr.h indirectly, .c files were left alone. Some of these files
clearly got ktr.h via header pollution in some scenarios, or tinderbox would
not be passing prior to this revision, but go ahead and explicitly include it
in files using it anyway.
Like r348026, these CUs did not show up in tinderbox as missing the include.
Reported by: peterj (arm64/mp_machdep.c)
X-MFC-With: r347984
Sponsored by: Dell EMC Isilon
kern_execve() locks text vnode exclusive to be able to set and clear
VV_TEXT flag. VV_TEXT is mutually exclusive with the v_writecount > 0
condition.
The change removes VV_TEXT, replacing it with the condition
v_writecount <= -1, and puts v_writecount under the vnode interlock.
Each text reference decrements v_writecount. To clear the text
reference when the segment is unmapped, it is recorded in the
vm_map_entry backed by the text file as MAP_ENTRY_VN_TEXT flag, and
v_writecount is incremented on the map entry removal
The operations like VOP_ADD_WRITECOUNT() and VOP_SET_TEXT() check that
v_writecount does not contradict the desired change. vn_writecheck()
is now racy and its use was eliminated everywhere except access.
Atomic check for writeability and increment of v_writecount is
performed by the VOP. vn_truncate() now increments v_writecount
around VOP_SETATTR() call, lack of which is arguably a bug on its own.
nullfs bypasses v_writecount to the lower vnode always, so nullfs
vnode has its own v_writecount correct, and lower vnode gets all
references, since object->handle is always lower vnode.
On the text vnode' vm object dealloc, the v_writecount value is reset
to zero, and deadfs vop_unset_text short-circuit the operation.
Reclamation of lowervp always reclaims all nullfs vnodes referencing
lowervp first, so no stray references are left.
Reviewed by: markj, trasz
Tested by: mjg, pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 month
Differential revision: https://reviews.freebsd.org/D19923
back to the lever before r343030. For 64-bit machines reduce it slightly,
too. Together with r343030 I bumped the limit up to the value we use at
Netflix to serve 100 Gbit/s of sendfile traffic, and it probably isn't a
good default.
Provide a loader tunable to change vnode pager pbufs count. Document it.
o In vm_pager_bufferinit() create pbuf_zone and start accounting on how many
pbufs are we going to have set.
In various subsystems that are going to utilize pbufs create private zones
via call to pbuf_zsecond_create(). The latter calls uma_zsecond_create(),
and sets a limit on created zone. After startup preallocate pbufs according
to requirements of all pbuf zones.
Subsystems that used to have a private limit with old allocator now have
private pbuf zones: md(4), fusefs, NFS client, smbfs, VFS cluster, FFS,
swap, vnode pager.
The following subsystems use shared pbuf zone: cam(4), nvme(4), physio(9),
aio(4). They should have their private limits, but changing that is out of
scope of this commit.
o Fetch tunable value of kern.nswbuf from init_param2() and while here move
NSWBUF_MIN to opt_param.h and eliminate opt_swap.h, that was holding only
this option.
Default values aren't touched by this commit, but they probably should be
reviewed wrt to modern hardware.
This change removes a tight bottleneck from sendfile(2) operation, that
uses pbufs in vnode pager. Other pagers also would benefit from faster
allocation.
Together with: gallatin
Tested by: pho
Add a new "interleave" allocation policy which stripes pages across
domains with a stride or width keeping contiguity within a multi-page
region.
Move the kernel to the dedicated numbered cpuset #2 making it possible
to assign kernel threads and memory policy separately from user. This
also eliminates the need for the complicated interrupt binding code.
Add a sysctl API for viewing and manipulating domainsets. Refactor some
of the cpuset_t manipulation code using the generic bitset type so that
it can be used for both. This probably belongs in a dedicated subr file.
Attempt to improve the include situation.
Reviewed by: kib
Discussed with: jhb (cpuset parts)
Tested by: pho (before review feedback)
Sponsored by: Netflix, Dell/EMC Isilon
Differential Revision: https://reviews.freebsd.org/D14839
global to per-domain state. Protect reservations with the free lock
from the domain that they belong to. Refactor to make vm domains more
of a first class object.
Reviewed by: markj, kib, gallatin
Tested by: pho
Sponsored by: Netflix, Dell/EMC Isilon
Differential Revision: https://reviews.freebsd.org/D14000
clear dirty bits for completely invalid blocks.
Otherwise we might not write out the last chunk that is shorter than
512 bytes, if the file end is not aligned on disk block boundary.
This become important after the r324794.
PR: 225586
Reported by: tris_vern@hotmail.com
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
Initially, only tag files that use BSD 4-Clause "Original" license.
RelNotes: yes
Differential Revision: https://reviews.freebsd.org/D13133
Only upgrade it to write mode if we need to clear dirty bits of the
partially valid page after EOF.
Suggested and reviewed by: alc
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks
If filesystem block size is less than the page size, it is possible
that the page-out run contains partially clean pages. E.g., the chunk
of the page might be bdwrite()-ed, or some thread performed bwrite()
on a buffer which references a chunk of the paged out page. As
result, the assertion added in r319975, which checked that all pages
in the run are dirty, does not hold on such filesystems.
One solution is to remove the assert, but it is undesirable, because
we do overwrite the valid on-disk content. I cannot provide a scenario
where such write would corrupt the file data, but I do not like it on
principle. Another, in my opinion proper, solution is to only write
parts of the pages still marked dirty. The patch implements this, it
skips clean blocks and only writes the dirty block runs.
Note that due to clustering, write one page might clean other pages in
the run, so the next write range must be calculated only after the
current range is written out.
More, due to a possible invalidation, and the fact that the object
lock is dropped and reacquired before the checks, it is possible that
the whole page-out pages run appears to consist of only clean pages.
For this reason, it is impossible to assert that there is some work
for the pageout method to do (i.e. assert that there is at least one
dirty page in the run). But such clearing can only occur due to
invalidation, and not due to a parallel write, because we own the
vnode lock exclusive.
Reported by: fsu
In collaboration with: pho
Reviewed by: alc, markj
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks
Differential revision: https://reviews.freebsd.org/D12668
Suppose that a file on NFS has partially filled last page, and this
page is dirty. NFS VOP_PAGEOUT() method only marks the the page clean
up to the block of the last written byte, leaving other blocks dirty.
Also any page which erronously exists in the vnode vm_object past EOF
is also left marked as dirty.
With the introduction of the buf-cache coherent pager, each pass of
syncer over the object with such page results in creation of B_DELWRI
buffer due to VOP_WRITE() call. This buffer is noted on next syncer
pass, which results e.g. a visible manifestation of shutdown never
finishing vnode sync. Note that before buf-cache coherency commit, a
dirty page might left never synced to server if a partial writes
occur.
Fix this by clearing dirty bits after EOF. Only blocks of the partial
page which are completely after EOF are marked clean, to avoid
possible user data loss.
Reported by: mav
Reviewed by: alc, markj
Tested by: mav, pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D11697
- Add asserts that the pages to write are dirty. The last page, if
partially written, is only required to be dirty, while completely
written pages should have all dirty bit set.
- Use uintmax_t to print vm_page pindexes.
- Use NULL instead of casted zero.
- Remove if () test which duplicated the loop ending condition.
- Miscellaneous style fixes.
Reviewed by: alc, markj (previous version)
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
in place. To do per-cpu stats, convert all fields that previously were
maintained in the vmmeters that sit in pcpus to counter(9).
- Since some vmmeter stats may be touched at very early stages of boot,
before we have set up UMA and we can do counter_u64_alloc(), provide an
early counter mechanism:
o Leave one spare uint64_t in struct pcpu, named pc_early_dummy_counter.
o Point counter(9) fields of vmmeter to pcpu[0].pc_early_dummy_counter,
so that at early stages of boot, before counters are allocated we already
point to a counter that can be safely written to.
o For sparc64 that required a whole dummy pcpu[MAXCPU] array.
Further related changes:
- Don't include vmmeter.h into pcpu.h.
- vm.stats.vm.v_swappgsout and vm.stats.vm.v_swappgsin changed to 64-bit,
to match kernel representation.
- struct vmmeter hidden under _KERNEL, and only vmstat(1) is an exclusion.
This is based on benno@'s 4-year old patch:
https://lists.freebsd.org/pipermail/freebsd-arch/2013-July/014471.html
Reviewed by: kib, gallatin, marius, lidl
Differential Revision: https://reviews.freebsd.org/D10156
