allocation and deallocation. This flag's principal use is shortly after
allocation. For such cases, clearing the flag is pointless. The only
unusual use of PG_ZERO is in vfs_bio_clrbuf(). However, allocbuf() never
requests a prezeroed page. So, vfs_bio_clrbuf() never sees a prezeroed
page.
Reviewed by: tegge@
on non-VCHR vnodes. This fixes a panic when reading data from files on a
filesystem with a small (less than a page) block size.
PR: 59271
Reviewed by: alc
vm_pageout_page_stats() from Giant.
- Modify vm_pager_put_pages() and vm_pager_page_unswapped() to expect the
vm object to be locked on entry. (All of the pager routines now expect
this.)
releasing the lock only if we are about to sleep (e.g., vm_pager_get_pages()
or vm_pager_has_pages()). If we sleep, we have marked the vm object with
the paging-in-progress flag.
comes along and flushes a file which has been mmap()'d SHARED/RW, with
dirty pages, it was flushing the underlying VM object asynchronously,
resulting in thousands of 8K writes. With this change the VM Object flushing
code will cluster dirty pages in 64K blocks.
Note that until the low memory deadlock issue is reviewed, it is not safe
to allow the pageout daemon to use this feature. Forced pageouts still
use fs block size'd ops for the moment.
MFC after: 3 days
indirectly through vm_page_protect(). The one remaining page flag that
is updated by vm_page_protect() is already being updated by our various
pmap implementations.
Note: A later commit will similarly change the VM_PROT_READ case and
eliminate vm_page_protect().
pmap_zero_page() and pmap_zero_page_area() were modified to accept
a struct vm_page * instead of a physical address, vm_page_zero_fill()
and vm_page_zero_fill_area() have served no purpose.
- v_vflag is protected by the vnode lock and is used when synchronization
with VOP calls is needed.
- v_iflag is protected by interlock and is used for dealing with vnode
management issues. These flags include X/O LOCK, FREE, DOOMED, etc.
- All accesses to v_iflag and v_vflag have either been locked or marked with
mp_fixme's.
- Many ASSERT_VOP_LOCKED calls have been added where the locking was not
clear.
- Many functions in vfs_subr.c were restructured to provide for stronger
locking.
Idea stolen from: BSD/OS
release of Giant. (Annotate as MPSAFE.)
o Also, in vnode_pager_alloc(), remove an unnecessary re-initialization
of struct vm_object::flags and move a statement that is duplicated
in both branches of an if-else.
