Commit Graph

80 Commits

Author SHA1 Message Date
Poul-Henning Kamp
119b6f4cf2 Use 2^N hash sizes rather than primesize, this replaces a division
with an and. (Submitted by davidg)

Preemptively record ".." values.

Reviewed by:	phk
1997-09-03 09:20:17 +00:00
Bruce Evans
e4ba6a82b0 Removed unused #includes. 1997-09-02 20:06:59 +00:00
Poul-Henning Kamp
a051452ae2 Change the 0xdeadb hack to a flag called VDOOMED.
Introduce VFREE which indicates that vnode is on freelist.
Rename vholdrele() to vdrop().
Create vfree() and vbusy() to add/delete vnode from freelist.
Add vfree()/vbusy() to keep (v_holdcnt != 0 || v_usecount != 0)
  vnodes off the freelist.
Generalize vhold()/v_holdcnt to mean "do not recycle".
Fix reassignbuf()s lack of use of vhold().
Use vhold() instead of checking v_cache_src list.
Remove vtouch(), the vnodes are always vget'ed soon enough
  after for it to have any measuable effect.
Add sysctl debug.freevnodes to keep track of things.
Move cache_purge() up in getnewvnodes to avoid race.
Decrement v_usecount after VOP_INACTIVE(), put a vhold() on
  it during VOP_INACTIVE()
Unmacroize vhold()/vdrop()
Print out VDOOMED and VFREE flags (XXX: should use %b)

Reviewed by:		dyson
1997-08-31 07:32:39 +00:00
Poul-Henning Kamp
0fa2443f0e Uncut&paste cache_lookup().
This unifies several times in theory indentical 50 lines of code.

The filesystems have a new method: vop_cachedlookup, which is the
meat of the lookup, and use vfs_cache_lookup() for their vop_lookup
method.  vfs_cache_lookup() will check the namecache and pass on
to the vop_cachedlookup method in case of a miss.

It's still the task of the individual filesystems to populate the
namecache with cache_enter().

Filesystems that do not use the namecache will just provide the
vop_lookup method as usual.
1997-08-26 07:32:51 +00:00
Poul-Henning Kamp
2401f27c25 remove unused MAXVNODEUSE macro. 1997-08-04 07:31:36 +00:00
Poul-Henning Kamp
b15a966ec6 1. Add a {pointer, v_id} pair to the vnode to store the reference to the
".." vnode.  This is cheaper storagewise than keeping it in the
    namecache, and it makes more sense since it's a 1:1 mapping.

2.  Also handle the case of "." more intelligently rather than stuff
    the namecache with pointless entries.

3.  Add two lists to the vnode and hang namecache entries which go from
    or to this vnode.  When cleaning a vnode, delete all namecache
    entries it invalidates.

4.  Never reuse namecache enties, malloc new ones when we need it, free
    old ones when they die.  No longer a hard limit on how many we can
    have.

5.  Remove the upper limit on namelength of namecache entries.

6.  Make a global list for negative namecache entries, limit their number
    to a sysctl'able (debug.ncnegfactor) fraction of the total namecache.
    Currently the default fraction is 1/16th.  (Suggestions for better
    default wanted!)

7.  Assign v_id correctly in the face of 32bit rollover.

8.  Remove the LRU list for namecache entries, not needed.  Remove the
    #ifdef NCH_STATISTICS stuff, it's not needed either.

9.  Use the vnode freelist as a true LRU list, also for namecache accesses.

10. Reuse vnodes more aggresively but also more selectively, if we can't
    reuse, malloc a new one.  There is no longer a hard limit on their
    number, they grow to the point where we don't reuse potentially
    usable vnodes.  A vnode will not get recycled if still has pages in
    core or if it is the source of namecache entries (Yes, this does
    indeed work :-)  "." and ".." are not namecache entries any longer...)

11. Do not overload the v_id field in namecache entries with whiteout
    information, use a char sized flags field instead, so we can get
    rid of the vpid and v_id fields from the namecache struct.  Since
    we're linked to the vnodes and purged when they're cleaned, we don't
    have to check the v_id any more.

12. NFS knew about the limitation on name length in the namecache, it
    shouldn't and doesn't now.

Bugs:
        The namecache statistics no longer includes the hits for ".."
        and "." hits.

Performance impact:
        Generally in the +/- 0.5% for "normal" workstations, but
        I hope this will allow the system to be selftuning over a
        bigger range of "special" applications.  The case where
        RAM is available but unused for cache because we don't have
        any vnodes should be gone.

Future work:
        Straighten out the namecache statistics.

        "desiredvnodes" is still used to (bogusly ?) size hash
        tables in the filesystems.

        I have still to find a way to safely free unused vnodes
        back so their number can shrink when not needed.

        There is a few uses of the v_id field left in the filesystems,
        scheduled for demolition at a later time.

        Maybe a one slot cache for unused namecache entries should
        be implemented to decrease the malloc/free frequency.
1997-05-04 09:17:38 +00:00
Bruce Evans
d8d6519c63 Fixed the hash formula. Lite2 doesn't have phashinit(), so Lite2's hash
formula uses `& nchash'.  This is very broken when nchash is a prime
number instead of 1 less than a power of 2, but the Lite2 formula was
merged in.

Merged some cosmetic changes from Lite2, rev.1.21 and Lite1.  The merge
was difficult because the Lite2 code is essentially ours (phk's) except
where Lite2 improved or broke it.

Summary of the Lite2 changes:
- in the copyright, phk's rights have been transferred to the Regents.
  This change should be reviewed.
- nchENOENT went away; the "no" vnode is now simply 0.
- comments were improved.
- style was "improved".
- goto instead of Fanatism (sic) was considered bad :-).
- there are some small changes to support whiteouts.
- new cache entries are added in more cases.  More work is required
  near here to change the hash table size if kern.desiredvnodes is
  changed using sysctl.
- rescanning of the hash bucket in cache_purgevfs() was removed.  This
  change should be reviewed.
1997-03-08 15:22:14 +00:00
Peter Wemm
6875d25465 Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.
1997-02-22 09:48:43 +00:00
John Dyson
996c772f58 This is the kernel Lite/2 commit. There are some requisite userland
changes, so don't expect to be able to run the kernel as-is (very well)
without the appropriate Lite/2 userland changes.

The system boots and can mount UFS filesystems.

Untested: ext2fs, msdosfs, NFS
Known problems: Incorrect Berkeley ID strings in some files.
		Mount_std mounts will not work until the getfsent
		library routine is changed.

Reviewed by:	various people
Submitted by:	Jeffery Hsu <hsu@freebsd.org>
1997-02-10 02:22:35 +00:00
Jordan K. Hubbard
1130b656e5 Make the long-awaited change from $Id$ to $FreeBSD$
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore.  This update would have been
insane otherwise.
1997-01-14 07:20:47 +00:00
John Dyson
bd7e5f992e Eliminated many redundant vm_map_lookup operations for vm_mmap.
Speed up for vfs_bio -- addition of a routine bqrelse to greatly diminish
	overhead for merged cache.
Efficiency improvement for vfs_cluster.  It used to do alot of redundant
	calls to cluster_rbuild.
Correct the ordering for vrele of .text and release of credentials.
Use the selective tlb update for 486/586/P6.
Numerous fixes to the size of objects allocated for files.  Additionally,
	fixes in the various pagers.
Fixes for proper positioning of vnode_pager_setsize in msdosfs and ext2fs.
Fixes in the swap pager for exhausted resources.  The pageout code
	will not as readily thrash.
Change the page queue flags (PG_ACTIVE, PG_INACTIVE, PG_FREE, PG_CACHE) into
	page queue indices (PQ_ACTIVE, PQ_INACTIVE, PQ_FREE, PQ_CACHE),
	thereby improving efficiency of several routines.
Eliminate even more unnecessary vm_page_protect operations.
Significantly speed up process forks.
Make vm_object_page_clean more efficient, thereby eliminating the pause
	that happens every 30seconds.
Make sequential clustered writes B_ASYNC instead of B_DELWRI even in the
	case of filesystems mounted async.
Fix a panic with busy pages when write clustering is done for non-VMIO
	buffers.
1996-01-19 04:00:31 +00:00
Poul-Henning Kamp
79c0c4b77f kern_conf.c: remove a now unused variable.
vfs_cache.c: Fix a very rare probelm in the vnode-cache.
Submitted by:	Terry Lambert <terry@lambert.org>
1995-12-22 15:56:35 +00:00
Poul-Henning Kamp
f708ef1b9e Another mega commit to staticize things. 1995-12-14 09:55:16 +00:00
Poul-Henning Kamp
a98ca4699e Second batch of cleanup changes.
This time mostly making a lot of things static and some unused
variables here and there.
1995-10-29 15:33:36 +00:00
Bruce Evans
28f8db1403 Eliminate sloppy common-style declarations. There should be none left for
the LINT configuation.
1995-07-29 11:44:31 +00:00
Rodney W. Grimes
9b2e535452 Remove trailing whitespace. 1995-05-30 08:16:23 +00:00
David Greenman
cf8ad5100d Fixed serious off by one bug I introduced that will likely cause the
machine to panic whenever the name cache fills up.

Submitted by:	John Dyson
1995-04-15 00:49:35 +00:00
David Greenman
22e53424b2 kern_subr.c:
Added a new type to uiomove - "UIO_NOCOPY" which causes it to update
pointers and counts, but doesn't do any data copying. This is needed
for upcoming changes to the way that the vnode pager does its page
outs.
Added a new hash init function call "phashinit" that allocates and
initializes a prime number sized hash table.

vfs_cache.c:
Changed hashing algorithm to use the remainder of dividing by a prime
number to improve the distribution characteristcs. Uses new phashinit
function in kern_subr.c.
1995-04-04 02:01:13 +00:00
David Greenman
d7e3d98a5e Patch from Kirk McKusick to fix a bug introduced in the Poul's vfs_cache
rewrite.
1995-03-19 09:33:51 +00:00
Poul-Henning Kamp
47f196941e Update a couple of counters. 1995-03-12 02:01:20 +00:00
David Greenman
914e6eb70d Whoops, back out that last change - I misread what Poul had done there. 1995-03-10 20:29:51 +00:00
David Greenman
dbd90d413f Don't thrash the name cache while trying to fill up the object cache.
(Make a new cache entry until desiredvnodes is reached).
1995-03-10 20:26:29 +00:00
Poul-Henning Kamp
b2e10d6d6f Clean up and improve the namecache.
1. We always keep one 16th of the vnodes on the freelist, so that the
namecache doesn't get trashed.  It used to be that it wasn't a problem, but
the only vnodes getting released these days are directories and things which
gets forced out of the VM/cache.  The latter is not numerous enough to keep
the pool of vnodes needed for the namecache sufficiently big.

2. Purge invalid entries in the namecache as soon as we notice them.  This
avoids a stale entry pushing out a valid entry on the LRU list.

3. Speed up the lookup in the namecache by avoid a special case branch.

4. Make the cache purge routines do the thing they're supposed to, and in
a decently efficient manner.

5. Make the size of the namecache follow the number of vnodes, so that we
can always point to all the vnodes we have in core.

6. Readability has gone way up.

7. Added a "options NCH_STATISTICS" feature that will gather more
detailed statistics on the performance of the namecache.

Reviewed by:	davidg
1995-03-09 20:23:45 +00:00
Poul-Henning Kamp
a0e8a1e29b Another little optimization to the nameicache.
If an entry is stale, ditch it.
1995-03-08 01:40:44 +00:00
Poul-Henning Kamp
2425396b27 Improve the quality of the hash used in the namei-cache. 1995-03-08 01:08:03 +00:00
Poul-Henning Kamp
30f467d84a Update vfs_cache.c to use the <sys/queue.h> macros. This makes it easier
to read, but doesn't change the speed.

Reviewed by:	phk
Obtained from:	via NetBSD
1995-03-06 06:45:52 +00:00
Poul-Henning Kamp
797f2d22f0 All of this is cosmetic. prototypes, #includes, printfs and so on. Makes
GCC a lot more silent.
1994-10-02 17:35:40 +00:00
David Greenman
3c4dd3568f Added $Id$ 1994-08-02 07:55:43 +00:00
Rodney W. Grimes
26f9a76710 The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.
Reviewed by:	Rodney W. Grimes
Submitted by:	John Dyson and David Greenman
1994-05-25 09:21:21 +00:00
Rodney W. Grimes
df8bae1de4 BSD 4.4 Lite Kernel Sources 1994-05-24 10:09:53 +00:00