On 9/22/15, Oliver Pinter <oliver.pin...@hardenedbsd.org> wrote:
> On 9/22/15, Kirk McKusick <mckus...@freebsd.org> wrote:
>> Author: mckusick
>> Date: Tue Sep 22 00:43:05 2015
>> New Revision: 288079
>> URL: https://svnweb.freebsd.org/changeset/base/288079
>>
>> Log:
>> MFC of 281677:
>>
>> More accurately collect name-cache statistics in sysctl functions
>> sysctl_debug_hashstat_nchash() and sysctl_debug_hashstat_rawnchash().
>> These changes are in preparation for allowing changes in the size
>> of the vnode hash tables driven by increases and decreases in the
>> maximum number of vnodes in the system.
>>
>> Reviewed by: kib@
>> Phabric: D2265
>>
>> MFC of 287497:
>>
>> Track changes to kern.maxvnodes and appropriately increase or decrease
>> the size of the name cache hash table (mapping file names to vnodes)
>> and the vnode hash table (mapping mount point and inode number to
>> vnode).
>> An appropriate locking strategy is the key to changing hash table sizes
>> while they are in active use.
>>
>> Reviewed by: kib
>> Tested by: Peter Holm
>> Differential Revision: https://reviews.freebsd.org/D2265
>>
>> Modified:
>> stable/10/sys/kern/vfs_cache.c
>> stable/10/sys/kern/vfs_hash.c
>> stable/10/sys/kern/vfs_subr.c
>> stable/10/sys/sys/vnode.h
>> Directory Properties:
>> stable/10/ (props changed)
>>
>> Modified: stable/10/sys/kern/vfs_cache.c
>> ==============================================================================
>> --- stable/10/sys/kern/vfs_cache.c Mon Sep 21 22:34:16 2015
>> (r288078)
>> +++ stable/10/sys/kern/vfs_cache.c Tue Sep 22 00:43:05 2015
>> (r288079)
>> @@ -330,23 +330,27 @@ sysctl_debug_hashstat_rawnchash(SYSCTL_H
>> int n_nchash;
>> int count;
>>
>> +retry:
>> n_nchash = nchash + 1; /* nchash is max index, not count */
>> if (!req->oldptr)
>> return SYSCTL_OUT(req, 0, n_nchash * sizeof(int));
>> -
>> - /* Scan hash tables for applicable entries */
>> - for (ncpp = nchashtbl; n_nchash > 0; n_nchash--, ncpp++) {
>> - CACHE_RLOCK();
>> - count = 0;
>> - LIST_FOREACH(ncp, ncpp, nc_hash) {
>> - count++;
>> - }
>> + cntbuf = malloc(n_nchash * sizeof(int), M_TEMP, M_ZERO | M_WAITOK);
>> + CACHE_RLOCK();
>> + if (n_nchash != nchash + 1) {
>> CACHE_RUNLOCK();
>> - error = SYSCTL_OUT(req, &count, sizeof(count));
>> - if (error)
>> - return (error);
>> + free(cntbuf, M_TEMP);
>> + goto retry;
>> }
>> - return (0);
>> + /* Scan hash tables counting entries */
>> + for (ncpp = nchashtbl, i = 0; i < n_nchash; ncpp++, i++)
>> + LIST_FOREACH(ncp, ncpp, nc_hash)
>> + cntbuf[i]++;
>> + CACHE_RUNLOCK();
>> + for (error = 0, i = 0; i < n_nchash; i++)
>> + if ((error = SYSCTL_OUT(req, &cntbuf[i], sizeof(int))) != 0)
>> + break;
>> + free(cntbuf, M_TEMP);
>> + return (error);
>> }
>> SYSCTL_PROC(_debug_hashstat, OID_AUTO, rawnchash,
>> CTLTYPE_INT|CTLFLAG_RD|
>> CTLFLAG_MPSAFE, 0, 0, sysctl_debug_hashstat_rawnchash, "S,int",
>> @@ -935,6 +939,44 @@ nchinit(void *dummy __unused)
>> }
>> SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nchinit, NULL);
>>
>> +void
>> +cache_changesize(int newmaxvnodes)
>> +{
>> + struct nchashhead *new_nchashtbl, *old_nchashtbl;
>> + u_long new_nchash, old_nchash;
>> + struct namecache *ncp;
>> + uint32_t hash;
>> + int i;
>> +
>> + new_nchashtbl = hashinit(newmaxvnodes * 2, M_VFSCACHE, &new_nchash);
>> + /* If same hash table size, nothing to do */
>> + if (nchash == new_nchash) {
>> + free(new_nchashtbl, M_VFSCACHE);
>> + return;
>> + }
>> + /*
>> + * Move everything from the old hash table to the new table.
>> + * None of the namecache entries in the table can be removed
>> + * because to do so, they have to be removed from the hash table.
>> + */
>> + CACHE_WLOCK();
>> + old_nchashtbl = nchashtbl;
>> + old_nchash = nchash;
>> + nchashtbl = new_nchashtbl;
>> + nchash = new_nchash;
>> + for (i = 0; i <= old_nchash; i++) {
>> + while ((ncp = LIST_FIRST(&old_nchashtbl[i])) != NULL) {
>> + hash = fnv_32_buf(nc_get_name(ncp), ncp->nc_nlen,
>> + FNV1_32_INIT);
>> + hash = fnv_32_buf(&ncp->nc_dvp, sizeof(ncp->nc_dvp),
>> + hash);
>> + LIST_REMOVE(ncp, nc_hash);
>> + LIST_INSERT_HEAD(NCHHASH(hash), ncp, nc_hash);
>> + }
>> + }
>> + CACHE_WUNLOCK();
>> + free(old_nchashtbl, M_VFSCACHE);
>> +}
>>
>> /*
>> * Invalidate all entries to a particular vnode.
>>
>> Modified: stable/10/sys/kern/vfs_hash.c
>> ==============================================================================
>> --- stable/10/sys/kern/vfs_hash.c Mon Sep 21 22:34:16 2015
>> (r288078)
>> +++ stable/10/sys/kern/vfs_hash.c Tue Sep 22 00:43:05 2015
>> (r288079)
>> @@ -160,3 +160,40 @@ vfs_hash_rehash(struct vnode *vp, u_int
>> vp->v_hash = hash;
>> mtx_unlock(&vfs_hash_mtx);
>> }
>> +
>> +void
>> +vfs_hash_changesize(int newmaxvnodes)
>> +{
>> + struct vfs_hash_head *vfs_hash_newtbl, *vfs_hash_oldtbl;
>> + u_long vfs_hash_newmask, vfs_hash_oldmask;
>> + struct vnode *vp;
>> + int i;
>> +
>> + vfs_hash_newtbl = hashinit(newmaxvnodes, M_VFS_HASH,
>> + &vfs_hash_newmask);
>> + /* If same hash table size, nothing to do */
>> + if (vfs_hash_mask == vfs_hash_newmask) {
>> + free(vfs_hash_newtbl, M_VFS_HASH);
>> + return;
>> + }
>> + /*
>> + * Move everything from the old hash table to the new table.
>> + * None of the vnodes in the table can be recycled because to
>> + * do so, they have to be removed from the hash table.
>> + */
>> + rw_wlock(&vfs_hash_lock);
>> + vfs_hash_oldtbl = vfs_hash_tbl;
>> + vfs_hash_oldmask = vfs_hash_mask;
>> + vfs_hash_tbl = vfs_hash_newtbl;
>> + vfs_hash_mask = vfs_hash_newmask;
>> + for (i = 0; i <= vfs_hash_oldmask; i++) {
>> + while ((vp = LIST_FIRST(&vfs_hash_oldtbl[i])) != NULL) {
>> + LIST_REMOVE(vp, v_hashlist);
>> + LIST_INSERT_HEAD(
>> + vfs_hash_bucket(vp->v_mount, vp->v_hash),
>> + vp, v_hashlist);
>> + }
>> + }
>> + rw_wunlock(&vfs_hash_lock);
>> + free(vfs_hash_oldtbl, M_VFS_HASH);
>> +}
>>
>> Modified: stable/10/sys/kern/vfs_subr.c
>> ==============================================================================
>> --- stable/10/sys/kern/vfs_subr.c Mon Sep 21 22:34:16 2015
>> (r288078)
>> +++ stable/10/sys/kern/vfs_subr.c Tue Sep 22 00:43:05 2015
>> (r288079)
>> @@ -280,8 +280,25 @@ static enum { SYNCER_RUNNING, SYNCER_SHU
>> * XXX desiredvnodes is historical cruft and should not exist.
>> */
>> int desiredvnodes;
>> -SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
>> - &desiredvnodes, 0, "Maximum number of vnodes");
>> +
>> +static int
>> +sysctl_update_desiredvnodes(SYSCTL_HANDLER_ARGS)
>> +{
>> + int error, old_desiredvnodes;
>> +
>> + old_desiredvnodes = desiredvnodes;
>> + if ((error = sysctl_handle_int(oidp, arg1, arg2, req)) != 0)
>> + return (error);
>> + if (old_desiredvnodes != desiredvnodes) {
>> + vfs_hash_changesize(desiredvnodes);
>> + cache_changesize(desiredvnodes);
>> + }
>> + return (0);
>> +}
>> +
>> +SYSCTL_PROC(_kern, KERN_MAXVNODES, maxvnodes,
>> + CTLTYPE_INT | CTLFLAG_MPSAFE | CTLFLAG_RW, &desiredvnodes, 0,
>> + sysctl_update_desiredvnodes, "I", "Maximum number of vnodes");
>> SYSCTL_ULONG(_kern, OID_AUTO, minvnodes, CTLFLAG_RW,
>> &wantfreevnodes, 0, "Minimum number of vnodes (legacy)");
>> static int vnlru_nowhere;
>>
>> Modified: stable/10/sys/sys/vnode.h
>> ==============================================================================
>> --- stable/10/sys/sys/vnode.h Mon Sep 21 22:34:16 2015
>> (r288078)
>> +++ stable/10/sys/sys/vnode.h Tue Sep 22 00:43:05 2015
>> (r288079)
>> @@ -600,6 +600,7 @@ struct vnode;
>> typedef int (*vn_get_ino_t)(struct mount *, void *, int, struct vnode
>> **);
>>
>> /* cache_* may belong in namei.h. */
>> +void cache_changesize(int newhashsize);
>> #define cache_enter(dvp, vp, cnp)
>> \
>> cache_enter_time(dvp, vp, cnp, NULL, NULL)
>> void cache_enter_time(struct vnode *dvp, struct vnode *vp,
>> @@ -836,6 +837,7 @@ int fifo_printinfo(struct vnode *);
>> /* vfs_hash.c */
>> typedef int vfs_hash_cmp_t(struct vnode *vp, void *arg);
>>
>> +void vfs_hash_changesize(int newhashsize);
>> int vfs_hash_get(const struct mount *mp, u_int hash, int flags, struct
>> thread *td, struct vnode **vpp, vfs_hash_cmp_t *fn, void *arg);
>> u_int vfs_hash_index(struct vnode *vp);
>> int vfs_hash_insert(struct vnode *vp, u_int hash, int flags, struct
>> thread
>> *td, struct vnode **vpp, vfs_hash_cmp_t *fn, void *arg);
>
> Seems like this commit breaks the build:
>
> --- vfs_hash.o ---
> /jenkins/workspace/HardenedBSD-10-STABLE-amd64/sys/kern/vfs_hash.c:184:2:
> error: implicit declaration of function 'rw_wlock' is invalid in C99
> [-Werror,-Wimplicit-function-declaration]
> rw_wlock(&vfs_hash_lock);
> ^
> /jenkins/workspace/HardenedBSD-10-STABLE-amd64/sys/kern/vfs_hash.c:184:12:
> error: use of undeclared identifier 'vfs_hash_lock'; did you mean
> 'vfs_hash_mask'?
> rw_wlock(&vfs_hash_lock);
> ^~~~~~~~~~~~~
> vfs_hash_mask
> /jenkins/workspace/HardenedBSD-10-STABLE-amd64/sys/kern/vfs_hash.c:42:18:
> note: 'vfs_hash_mask' declared here
> static u_long vfs_hash_mask;
> ^
> /jenkins/workspace/HardenedBSD-10-STABLE-amd64/sys/kern/vfs_hash.c:197:2:
> error: implicit declaration of function 'rw_wunlock' is invalid in C99
> [-Werror,-Wimplicit-function-declaration]
> rw_wunlock(&vfs_hash_lock);
> ^
> /jenkins/workspace/HardenedBSD-10-STABLE-amd64/sys/kern/vfs_hash.c:197:2:
> note: did you mean 'rw_wlock'?
> /jenkins/workspace/HardenedBSD-10-STABLE-amd64/sys/kern/vfs_hash.c:184:2:
> note: 'rw_wlock' declared here
> rw_wlock(&vfs_hash_lock);
> ^
> /jenkins/workspace/HardenedBSD-10-STABLE-amd64/sys/kern/vfs_hash.c:197:14:
> error: use of undeclared identifier 'vfs_hash_lock'; did you mean
> 'vfs_hash_mask'?
> rw_wunlock(&vfs_hash_lock);
> ^~~~~~~~~~~~~
> vfs_hash_mask
> /jenkins/workspace/HardenedBSD-10-STABLE-amd64/sys/kern/vfs_hash.c:42:18:
> note: 'vfs_hash_mask' declared here
> static u_long vfs_hash_mask;
> ^
> 4 errors generated.
> *** [vfs_hash.o] Error code 1
>
> make[2]: stopped in
> /usr/obj/jenkins/workspace/HardenedBSD-10-STABLE-amd64/sys/HARDENEDBSD
> --- vfs_export.o ---
> ctfconvert -L VERSION -g vfs_export.o
>
> http://jenkins.hardenedbsd.org:8180/jenkins/job/HardenedBSD-10-STABLE-amd64/99/console
The following commit is missing from MFC:
commit 09f7a46ec71137e29d82d2f0811a7f81b6142266
Author: mjg <m...@freebsd.org>
Date: Tue Dec 30 21:40:45 2014 +0000
Convert vfs hash lock from a mutex to an rwlock.
>
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>
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