64-bits numbers. ktr_tracepoint() infacts casts all the passed value to
u_long values as that is what the ktr entries can handle.
However, we have to work a lot with vm_pindex_t which are always 64-bit
also on 32-bits architectures (most notable case being i386).
Use macros to split the 64 bits printing into 32-bits chunks which
KTR can correctly handle.
Reported and tested by: flo
There are two aspects to the sequential access optimization: (1) read ahead
of pages that are expected to be accessed in the near future and (2) unmap
and cache behind of pages that are not expected to be accessed again. This
revision changes both aspects.
The read ahead optimization is now more effective. It starts with the same
initial read window as before, but arithmetically grows the window on
sequential page faults. This can yield increased read bandwidth. For
example, on one of my machines, a program using mmap() to read a file that
is several times larger than the machine's physical memory takes about 17%
less time to complete.
The unmap and cache behind optimization is now more selectively applied.
The read ahead window must grow to its maximum size before unmap and cache
behind is performed. This significantly reduces the number of times that
pages are unmapped and cached only to be reactivated a short time later.
The unmap and cache behind optimization now clears each page's referenced
flag. Previously, in the case of dirty pages, if the containing file was
still mapped at the time that the page daemon examined the dirty pages,
they would be reactivated.
From a stylistic standpoint, this revision also cleanly separates the
implementation of the read ahead and unmap/cache behind optimizations.
Glanced at: kib
MFC after: 2 weeks
the page. This PMAP requires an additional lock besides the PMAP lock
in pmap_extract_and_hold(), which vm_page_pa_tryrelock() did not release.
Suggested by: kib
MFC after: 4 days
cover the initial stack size. For MCL_WIREFUTURE maps, the subsequent
call to vm_map_wire() to wire the whole stack region fails due to
VM_MAP_WIRE_NOHOLES flag.
Use the VM_MAP_WIRE_HOLESOK to only wire mapped part of the stack.
Reported and tested by: Sushanth Rai <sushanth_rai yahoo com>
Reviewed by: alc
MFC after: 1 week
accesses of the cache member of vm_object objects.
- Use novel vm_page_is_cached() for checks outside of the vm subsystem.
Reviewed by: alc
MFC after: 2 weeks
X-MFC: r234039
that it will be freed to the cache pool rather than the default pool.
Otherwise, the cached pages within the reservation may be recycled sooner
than necessary.
Reported by: Andrey Zonov
(if not already fictious) the code can panic when trying to first insert
a fictious page because of the overridden pindex.
Fix this by applying the same spinning pattern of vm_page_rename().
Reported by: pho
vm_page_cache_remove() should only be used in very little and specific
cases (and marked as static likely) where the callers is going to take
care also of the page flags appropriately, otherwise one can end up
with a corrupted page.
Reported by: pho
a pair of records similar to syscall entry and return that a user can
use to determine how long page faults take. The new ktrace records are
enabled via the 'p' trace type, and are enabled in the default set of
trace points.
Reviewed by: kib
MFC after: 2 weeks
to enable the collection of counts of synchronous and asynchronous
reads and writes for its associated filesystem. The counts are
displayed using `mount -v'.
Ensure that buffers used for paging indicate the vnode from
which they are operating so that counts of paging I/O operations
from the filesystem are collected.
This checkin only adds the setting of the mount point for the
UFS/FFS filesystem, but it would be trivial to add the setting
and clearing of the mount point at filesystem mount/unmount
time for other filesystems too.
Reviewed by: kib
kernel.
When access restrictions are added to a page table entry, we flush the
corresponding virtual address mapping from the TLB. In contrast, when
access restrictions are removed from a page table entry, we do not
flush the virtual address mapping from the TLB. This is exactly as
recommended in AMD's documentation. In effect, when access
restrictions are removed from a page table entry, AMD's MMUs will
transparently refresh a stale TLB entry. In short, this saves us from
having to perform potentially costly TLB flushes. In contrast,
Intel's MMUs are allowed to generate a spurious page fault based upon
the stale TLB entry. Usually, such spurious page faults are handled
by vm_fault() without incident. However, when we are executing
no-fault sections of the kernel, we are not allowed to execute
vm_fault(). This change introduces special-case handling for spurious
page faults that occur in no-fault sections of the kernel.
In collaboration with: kib
Tested by: gibbs (an earlier version)
I would also like to acknowledge Hiroki Sato's assistance in
diagnosing this problem.
MFC after: 1 week
than 4GB. Specifically, the inlined version of 'ptoa' of the the 'int'
count of pages overflowed on 64-bit platforms. While here, change
vm_object_madvise() to accept two vm_pindex_t parameters (start and end)
rather than a (start, count) tuple to match other VM APIs as suggested
by alc@.
if the filesystem performed short write and we are skipping the page
due to this.
Propogate write error from the pager back to the callers of
vm_pageout_flush(). Report the failure to write a page from the
requested range as the FALSE return value from vm_object_page_clean(),
and propagate it back to msync(2) to return EIO to usermode.
While there, convert the clearobjflags variable in the
vm_object_page_clean() and arguments of the helper functions to
boolean.
PR: kern/165927
Reviewed by: alc
MFC after: 2 weeks
- Fix bugs in the free path where the pages were not unwired and
relevant locking wasn't acquired.
- Introduce the rnode_map, submap of kernel_map, where to allocate from.
The reason is that, in architectures without direct-mapping,
kmem_alloc*() will try to insert the newly created mapping while
holding the vm_object lock introducing a LOR or lock recursion.
rnode_map is however a leafly-used submap, thus there cannot be any
deadlock.
Notes: Size the submap in order to be, by default, around 64 MB and
decrase the size of the nodes as the allocation will be much smaller
(and when the compacting code in the vm_radix will be implemented this
will aim for much less space to be used). However note that the
size of the submap can be changed at boot time via the
hw.rnode_map_scale scaling factor.
- Use uma_zone_set_max() covering the size of the submap.
Tested by: flo
still as it can be useful.
- Make most of the interface private as it is unnecessary public right
now. This will help in making nodes changing with arch and still avoid
namespace pollution.
external pagers in Mach. FreeBSD doesn't implement external pagers.
Moreover, it don't pageout the kernel object. So, the reasons for
having code don't hold.
Reviewed by: kib
MFC after: 6 weeks
v_writecount. Keep the amount of the virtual address space used by
the mappings in the new vm_object un_pager.vnp.writemappings
counter. The vnode v_writecount is incremented when writemappings gets
non-zero value, and decremented when writemappings is returned to
zero.
Writeable shared vnode-backed mappings are accounted for in vm_mmap(),
and vm_map_insert() is instructed to set MAP_ENTRY_VN_WRITECNT flag on
the created map entry. During deferred map entry deallocation,
vm_map_process_deferred() checks for MAP_ENTRY_VN_WRITECOUNT and
decrements writemappings for the vm object.
Now, the writeable mount cannot be demoted to read-only while
writeable shared mappings of the vnodes from the mount point
exist. Also, execve(2) fails for such files with ETXTBUSY, as it
should be.
Noted by: tegge
Reviewed by: tegge (long time ago, early version), alc
Tested by: pho
MFC after: 3 weeks
