Commit Graph

20 Commits

Author SHA1 Message Date
chs 64c6d1d2dc a whole bunch of changes to improve performance and robustness under load:
- remove special treatment of pager_map mappings in pmaps.  this is
   required now, since I've removed the globals that expose the address range.
   pager_map now uses pmap_kenter_pa() instead of pmap_enter(), so there's
   no longer any need to special-case it.
 - eliminate struct uvm_vnode by moving its fields into struct vnode.
 - rewrite the pageout path.  the pager is now responsible for handling the
   high-level requests instead of only getting control after a bunch of work
   has already been done on its behalf.  this will allow us to UBCify LFS,
   which needs tighter control over its pages than other filesystems do.
   writing a page to disk no longer requires making it read-only, which
   allows us to write wired pages without causing all kinds of havoc.
 - use a new PG_PAGEOUT flag to indicate that a page should be freed
   on behalf of the pagedaemon when it's unlocked.  this flag is very similar
   to PG_RELEASED, but unlike PG_RELEASED, PG_PAGEOUT can be cleared if the
   pageout fails due to eg. an indirect-block buffer being locked.
   this allows us to remove the "version" field from struct vm_page,
   and together with shrinking "loan_count" from 32 bits to 16,
   struct vm_page is now 4 bytes smaller.
 - no longer use PG_RELEASED for swap-backed pages.  if the page is busy
   because it's being paged out, we can't release the swap slot to be
   reallocated until that write is complete, but unlike with vnodes we
   don't keep a count of in-progress writes so there's no good way to
   know when the write is done.  instead, when we need to free a busy
   swap-backed page, just sleep until we can get it busy ourselves.
 - implement a fast-path for extending writes which allows us to avoid
   zeroing new pages.  this substantially reduces cpu usage.
 - encapsulate the data used by the genfs code in a struct genfs_node,
   which must be the first element of the filesystem-specific vnode data
   for filesystems which use genfs_{get,put}pages().
 - eliminate many of the UVM pagerops, since they aren't needed anymore
   now that the pager "put" operation is a higher-level operation.
 - enhance the genfs code to allow NFS to use the genfs_{get,put}pages
   instead of a modified copy.
 - clean up struct vnode by removing all the fields that used to be used by
   the vfs_cluster.c code (which we don't use anymore with UBC).
 - remove kmem_object and mb_object since they were useless.
   instead of allocating pages to these objects, we now just allocate
   pages with no object.  such pages are mapped in the kernel until they
   are freed, so we can use the mapping to find the page to free it.
   this allows us to remove splvm() protection in several places.

The sum of all these changes improves write throughput on my
decstation 5000/200 to within 1% of the rate of NetBSD 1.5
and reduces the elapsed time for "make release" of a NetBSD 1.5
source tree on my 128MB pc to 10% less than a 1.5 kernel took.
2001-09-15 20:36:31 +00:00
thorpej 8217ab697c Since a page can be on only one of ACTIVE or INACTIVE queues at
any given time, turn two consecutive if statements into an if-else-if
construct.
2001-06-27 23:57:16 +00:00
chs 3845302904 remove trailing whitespace. 2001-05-25 04:06:11 +00:00
ross 892627dd05 Merge the swap-backed and object-backed inactive lists. 2001-05-22 00:44:44 +00:00
thorpej 1779f8f71b Page scanner improvements, behavior is actually a bit more like
Mach VM's now.  Specific changes:
- Pages now need not have all of their mappings removed before being
  put on the inactive list.  They only need to have the "referenced"
  attribute cleared.  This makes putting pages onto the inactive list
  much more efficient.  In order to eliminate redundant clearings of
  "refrenced", callers of uvm_pagedeactivate() must now do this
  themselves.
- When checking the "modified" attribute for a page (for clearing
  PG_CLEAN), make sure to only do it if PG_CLEAN is currently set on
  the page (saves a potentially expensive pmap operation).
- When scanning the inactive list, if a page is referenced, reactivate
  it (this part was actually added in uvm_pdaemon.c,v 1.27).  This
  now works properly now that pages on the inactive list are allowed to
  have mappings.
- When scanning the inactive list and considering a page for freeing,
  remove all mappings, and then check the "modified" attribute if the
  page is marked PG_CLEAN.
- When scanning the active list, if the page was referenced since its
  last sweep by the scanner, don't deactivate it.  (This part was
  actually added in uvm_pdaemon.c,v 1.28.)

These changes greatly improve interactive performance during
moderate to high memory and I/O load.
2001-01-28 23:30:42 +00:00
thorpej f4395a4eae splimp() -> splvm() 2001-01-14 02:10:01 +00:00
chs 1ec37ad27a use queue.h macros and KASSERT(). 2000-11-27 07:47:42 +00:00
thorpej d45c9982df __predict_false() DIAGNOSTIC error checks. 2000-05-08 23:11:53 +00:00
kleink 6e5b64c8a0 Merge parts of chs-ubc2 into the trunk:
Add a new type voff_t (defined as a synonym for off_t) to describe offsets
into uvm objects, and update the appropriate interfaces to use it, the
most visible effect being the ability to mmap() file offsets beyond
the range of a vaddr_t.

Originally by Chuck Silvers; blame me for problems caused by merging this
into non-UBC.
2000-03-26 20:54:45 +00:00
chs f3a668ed84 eliminate the PMAP_NEW option by making it required for all ports.
ports which previously had no support for PMAP_NEW now implement
the pmap_k* interfaces as wrappers around the non-k versions.
1999-09-12 01:16:55 +00:00
thorpej 6eb9ee7cd8 - Change uvm_{lock,unlock}_fpageq() to return/take the previous interrupt
level directly, instead of making the caller wrap the calls in
  splimp()/splx().
- Add a comment documenting that interrupts that cause memory allocation
  must be blocked while the free page queue is locked.

Since interrupts must be blocked while this lock is asserted, tying them
together like this helps to prevent mistakes.
1999-05-24 19:10:57 +00:00
mrg a0139bc39d remove now >1 year old pre-release message. 1999-03-25 18:48:49 +00:00
eeh a2dd74ed79 Merge paddr_t changes into the main branch. 1998-08-13 02:10:37 +00:00
thorpej 7fd701e0fa Add support for multiple memory free lists. There is at least one
default free list, and 0 - N additional free list, in order of descending
priority.

A new page allocation function, uvm_pagealloc_strat(), has been added,
providing three page allocation strategies:

	- normal: high -> low priority free list walk, taking the
	  page off the first free list that has one.

	- only: attempt to allocate a page only from the specified free
	  list, failing if that free list has none available.

	- fallback: if `only' fails, fall back on `normal'.

uvm_pagealloc(...) is provided for normal use (and is a synonym for
uvm_pagealloc_strat(..., UVM_PGA_STRAT_NORMAL, 0); the free list argument
is ignored for the `normal' case).

uvm_page_physload() now specified which free list the pages will be
loaded onto.  This means that some platforms which have multiple physical
memory segments may define additional vm_physsegs if they wish to break
individual physical segments into differing priorities.

Machine-dependent code must define _at least_ the following constants
in <machine/vmparam.h>:

	VM_NFREELIST: the number of free lists the system will have

	VM_FREELIST_DEFAULT: the default freelist (should always be 0,
	but is defined in machdep code so that it's with all of the
	other free list-related constants).

Additional free list names may be defined by machine-dependent code, but
they will only be used by machine-dependent code (e.g. for loading the
vm_physsegs).
1998-07-08 04:28:27 +00:00
chuck e6da5a01e4 remove tmpwire arg from uvm_pagewire() -- it isn't needed anymore.
noted by chuck s.
1998-03-22 21:29:30 +00:00
mrg 8106d13596 KNF. 1998-03-09 00:58:55 +00:00
perry 021fdb646a add/cleanup multiple inclusion protection. 1998-02-10 02:34:17 +00:00
mrg 1f6b921cf7 restore rcsids 1998-02-07 11:07:38 +00:00
thorpej 9eb328b495 RCS ID police. 1998-02-06 22:26:13 +00:00
mrg f2caacc717 initial import of the new virtual memory system, UVM, into -current.
UVM was written by chuck cranor <chuck@maria.wustl.edu>, with some
minor portions derived from the old Mach code.  i provided some help
getting swap and paging working, and other bug fixes/ideas.  chuck
silvers <chuq@chuq.com> also provided some other fixes.

this is the UVM kernel code portion.


this will be KNF'd shortly.  :-)
1998-02-05 06:25:08 +00:00