shm_dotruncate() and vnode_pager_setsize(). Specifically, if the length of
a shared memory object or a file is truncated such that the length modulo
the page size is between 1 and 511, then all of the page's dirty bits were
cleared. Now, a dirty bit is cleared only if the corresponding block is
truncated in its entirety.
that vnode_pager_input_smlfs() zeroes the page, it should not mark the page
as valid until after the page is zeroed. Otherwise, the page could be
mapped for read access (e.g., by vm_map_pmap_enter()) before the page is
zeroed. Reviewed by: tegge
Eliminate gratuitous clearing of the page's dirty mask by
vnode_pager_input_smlfs(). Instead, assert that the page is clean.
Reviewed by: tegge
Eliminate some blank lines.
Eliminate pointless calls to pmap_clear_modify() and vm_page_undirty() from
vnode_pager_input_old(). The page is not mapped. Therefore, it cannot have
any page table entries that are modified.
Eliminate an incorrect comment from vnode_pager_generic_getpages().
pmap_clear_modify() on a page is pointless if that page is not mapped or
it is only mapped for read access. Instead, assert that the page is not
mapped or not mapped for write access as appropriate.
Eliminate unnecessary clearing of a page's dirty mask. Instead, assert
that the page's dirty mask is clear.
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
acquire vnode lock for OBJT_VNODE object after map lock is dropped.
Because we have the busy page(s) in the object, sleeping there would
result in deadlock with vnode resize. Try to get lock without sleeping,
and, if the attempt failed, drop the state, lock the vnode, and restart
the fault handler from the start with already locked vnode.
Because the vnode_pager_lock() function is inlined in vm_fault(),
axe it.
Based on suggestion by: alc
Reviewed by: tegge, alc
Tested by: pho
to downgrade the exclusive lock to shared one when exclusive lock owner
requested shared lock. New lockmgr panics instead.
The vnode_pager_lock function requests shared lock on the vnode backing
the OBJT_VNODE, and can be called when the current thread already holds
an exlcusive lock on the vnode. For instance, it happens when handling
page fault from the VOP_WRITE() uiomove that writes to the file, with
the faulted in page fetched from the vm object backed by the same file.
We then get the situation described above.
Verify whether the vnode is already exclusively locked by the curthread
and request recursed exclusive vnode lock instead of shared, if true.
Reported by: gallatin
Discussed with: attilio
Directory IO without a VM object will store data in 'malloced' buffers
severely limiting caching of the data. Without this change VM objects for
directories are only created on an open() of the directory.
TODO: Inline test if VM object already exists to avoid locking/function call
overhead.
Tested by: kris@
Reviewed by: jeff@
Reported by: David Filo
conjuction with 'thread' argument passing which is always curthread.
Remove the unuseful extra-argument and pass explicitly curthread to lower
layer functions, when necessary.
KPI results broken by this change, which should affect several ports, so
version bumping and manpage update will be further committed.
Tested by: kris, pho, Diego Sardina <siarodx at gmail dot com>
Remove this argument and pass curthread directly to underlying
VOP_LOCK1() VFS method. This modify makes the code cleaner and in
particular remove an annoying dependence helping next lockmgr() cleanup.
KPI results, obviously, changed.
Manpage and FreeBSD_version will be updated through further commits.
As a side note, would be valuable to say that next commits will address
a similar cleanup about VFS methods, in particular vop_lock1 and
vop_unlock.
Tested by: Diego Sardina <siarodx at gmail dot com>,
Andrea Di Pasquale <whyx dot it at gmail dot com>
comments from vnode_pager_setsize(). This call was introduced in
revision 1.140 to address a problem that no longer exists.
Specifically, pmap_zero_page_area() has replaced a (possibly)
problematic implementation of page zeroing that was based on
vm_pager_map(), bzero(), and vm_pager_unmap().
cache: vnode_pager_setsize() must handle the case where a file is
truncated to a non-page-size-aligned boundary and there is a cached
page underlying the new end of file.
Reported by: kris, tegge
Tested by: kris
MFC after: 3 days
Now, we assume no more sched_lock protection for some of them and use the
distribuited loads method for vmmeter (distribuited through CPUs).
Reviewed by: alc, bde
Approved by: jeff (mentor)
Probabilly, a general approach is not the better solution here, so we should
solve the sched_lock protection problems separately.
Requested by: alc
Approved by: jeff (mentor)
vmcnts. This can be used to abstract away pcpu details but also changes
to use atomics for all counters now. This means sched lock is no longer
responsible for protecting counts in the switch routines.
Contributed by: Attilio Rao <attilio@FreeBSD.org>
it introduced a check after the call to file system's get pages method
that assumes that the get pages method does not change the array of pages
that is passed to it. In the case of vnode_pager_generic_getpages(),
this assumption has been incorrect. The contents of the array of pages
may be shifted by vnode_pager_generic_getpages(). Likely, the problem
has been hidden by vnode_pager_haspage() limiting the set of pages that
are passed to vnode_pager_generic_getpages() such that a shift never
occurs.
The fix implemented herein is to adjust the pointer to the array of pages
rather than shifting the pages within the array.
MFC after: 3 weeks
Fix suggested by: tegge
an error returned by VOP_BMAP() and a hole in the file.
Change the callers to vnode_pager_addr() such that they return
VM_PAGER_ERROR when VOP_BMAP fails instead of a zero-filled page.
Reviewed by: tegge
MFC after: 3 weeks
vnode_pager_generic_getpages(): (1) that VOP_BMAP() is unsupported by the
underlying file system and (2) an error in performing the VOP_BMAP().
Previously, vnode_pager_generic_getpages() assumed that all errors were
of the first type. If, in fact, the error was of the second type, the
likely outcome was for the process to become permanently blocked on a busy
page.
MFC after: 3 weeks
Reviewed by: tegge
synchronized by the lock on the object containing the page.
Transition PG_WANTED and PG_SWAPINPROG to use the new field,
eliminating the need for holding the page queues lock when setting
or clearing these flags. Rename PG_WANTED and PG_SWAPINPROG to
VPO_WANTED and VPO_SWAPINPROG, respectively.
Eliminate the assertion that the page queues lock is held in
vm_page_io_finish().
Eliminate the acquisition and release of the page queues lock
around calls to vm_page_io_finish() in kern_sendfile() and
vfs_unbusy_pages().
be called without any vnode locks held. Remove calls to vn_start_write() and
vn_finished_write() in vnode_pager_putpages() and add these calls before the
vnode lock is obtained to most of the callers that don't already have them.
lock also protects this flag so it is not necessary.
- Don't rely on v_mount to detect whether or not we've been recycled, use
the more appropriate VI_DOOMED instead.
Sponsored by: Isilon Systems, Inc.
MFC After: 1 week
The former type, size_t, was causing truncation to 32 bits on i386,
which immediately led to undersizing of VM objects backed by
files >4GB. In particular, sendfile(2) was broken for such files.
PR: kern/92243
MFC after: 5 days
vm_pager_init() is run before required nswbuf variable has been set
to correct value. This caused system to run with single pbuf available
for vnode_pager. Handle both cluster_pbuf_freecnt and vnode_pbuf_freecnt
variable in the same way.
Reported by: ade
Obtained from: alc
MFC after: 2 days
underlying vnode requires Giant.
- In vm_fault only acquire Giant if the underlying object has NEEDSGIANT
set.
- In vm_object_shadow inherit the NEEDSGIANT flag from the backing object.
down. If we have dirty pages, the putpages routine will need to know
what the vnode's object is so that it may write out dirty pages.
Pointy hat: phk
Found by: obrien
patch from kan@).
Pull bufobj_invalbuf() out of vinvalbuf() and make g_vfs call it on
close. This is not yet a generally safe function, but for this very
specific use it is safe. This solves the problem with buffers not
being flushed by unmount or after failed mount attempts.
the name Sande^H^H^H^H^Hvnode_create_vobject().
Make the new function take a size argument which removes the need for
a VOP_STAT() or a very pessimistic guess for disks.
Call that new function from vop_stdcreatevobject().
Make vnode_pager_alloc() private now that its only user came home.
- Use VFS_LOCK_GIANT() rather than directly acquiring giant in places
where giant is only held because vfs requires it.
Sponsored By: Isilon Systems, Inc.
