freebsd-dev/sys/fs/pseudofs/pseudofs_internal.h
Mateusz Guzik 2e310f6f72 pseudofs: hashed vncache
Vast majority of uses the cache are just checking if there is an entry
present on process exit (and evicting it if so). Both checking and
eviction process are very expensive and put the lock protecting it high
up on the profile during poudriere -j 104.

Convert the linked list into a hash. This allows to almost always avoid
taking the lock in the first place (and consequently almost removes it
from the profile). Note only one lock is preserved as a split did not
meaningfully impact contention.

Should the cache be used for something it will still run into contention
issues. The code needs a rewrite, but should someone want to tidy it up
further the following can be done:

1) per-chain locks (or at least an array)
2) hashing by something else than just pid

Sponsored by:	The FreeBSD Foundation
2019-10-22 22:52:53 +00:00

213 lines
5.0 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 2001 Dag-Erling Coïdan Smørgrav
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _PSEUDOFS_INTERNAL_H_INCLUDED
#define _PSEUDOFS_INTERNAL_H_INCLUDED
/*
* Sysctl subtree
*/
SYSCTL_DECL(_vfs_pfs);
/*
* Vnode data
*/
struct pfs_vdata {
struct pfs_node *pvd_pn;
pid_t pvd_pid;
struct vnode *pvd_vnode;
SLIST_ENTRY(pfs_vdata) pvd_hash;
};
/*
* Vnode cache
*/
void pfs_vncache_load (void);
void pfs_vncache_unload (void);
int pfs_vncache_alloc (struct mount *, struct vnode **,
struct pfs_node *, pid_t pid);
int pfs_vncache_free (struct vnode *);
/*
* File number bitmap
*/
void pfs_fileno_init (struct pfs_info *);
void pfs_fileno_uninit (struct pfs_info *);
void pfs_fileno_alloc (struct pfs_node *);
void pfs_fileno_free (struct pfs_node *);
/*
* Debugging
*/
#ifdef PSEUDOFS_TRACE
extern int pfs_trace;
#define PFS_TRACE(foo) \
do { \
if (pfs_trace) { \
printf("%s(): line %d: ", __func__, __LINE__); \
printf foo ; \
printf("\n"); \
} \
} while (0)
#define PFS_RETURN(err) \
do { \
if (pfs_trace) { \
printf("%s(): line %d: returning %d\n", \
__func__, __LINE__, err); \
} \
return (err); \
} while (0)
#else
#define PFS_TRACE(foo) \
do { /* nothing */ } while (0)
#define PFS_RETURN(err) \
return (err)
#endif
/*
* Inline helpers for locking
*/
static inline void
pfs_lock(struct pfs_node *pn)
{
mtx_lock(&pn->pn_mutex);
}
static inline void
pfs_unlock(struct pfs_node *pn)
{
mtx_unlock(&pn->pn_mutex);
}
static inline void
pfs_assert_owned(struct pfs_node *pn)
{
mtx_assert(&pn->pn_mutex, MA_OWNED);
}
static inline void
pfs_assert_not_owned(struct pfs_node *pn)
{
mtx_assert(&pn->pn_mutex, MA_NOTOWNED);
}
static inline int
pn_fill(PFS_FILL_ARGS)
{
PFS_TRACE(("%s", pn->pn_name));
KASSERT(pn->pn_fill != NULL, ("%s(): no callback", __func__));
if (p != NULL) {
PROC_LOCK_ASSERT(p, MA_NOTOWNED);
PROC_ASSERT_HELD(p);
}
pfs_assert_not_owned(pn);
return ((pn->pn_fill)(PFS_FILL_ARGNAMES));
}
static inline int
pn_attr(PFS_ATTR_ARGS)
{
PFS_TRACE(("%s", pn->pn_name));
KASSERT(pn->pn_attr != NULL, ("%s(): no callback", __func__));
if (p != NULL)
PROC_LOCK_ASSERT(p, MA_OWNED);
pfs_assert_not_owned(pn);
return ((pn->pn_attr)(PFS_ATTR_ARGNAMES));
}
static inline int
pn_vis(PFS_VIS_ARGS)
{
PFS_TRACE(("%s", pn->pn_name));
KASSERT(pn->pn_vis != NULL, ("%s(): no callback", __func__));
KASSERT(p != NULL, ("%s(): no process", __func__));
PROC_LOCK_ASSERT(p, MA_OWNED);
pfs_assert_not_owned(pn);
return ((pn->pn_vis)(PFS_VIS_ARGNAMES));
}
static inline int
pn_ioctl(PFS_IOCTL_ARGS)
{
PFS_TRACE(("%s", pn->pn_name));
KASSERT(pn->pn_ioctl != NULL, ("%s(): no callback", __func__));
if (p != NULL)
PROC_LOCK_ASSERT(p, MA_OWNED);
pfs_assert_not_owned(pn);
return ((pn->pn_ioctl)(PFS_IOCTL_ARGNAMES));
}
static inline int
pn_getextattr(PFS_GETEXTATTR_ARGS)
{
PFS_TRACE(("%s", pn->pn_name));
KASSERT(pn->pn_getextattr != NULL, ("%s(): no callback", __func__));
if (p != NULL)
PROC_LOCK_ASSERT(p, MA_OWNED);
pfs_assert_not_owned(pn);
return ((pn->pn_getextattr)(PFS_GETEXTATTR_ARGNAMES));
}
static inline int
pn_close(PFS_CLOSE_ARGS)
{
PFS_TRACE(("%s", pn->pn_name));
KASSERT(pn->pn_close != NULL, ("%s(): no callback", __func__));
if (p != NULL)
PROC_LOCK_ASSERT(p, MA_OWNED);
pfs_assert_not_owned(pn);
return ((pn->pn_close)(PFS_CLOSE_ARGNAMES));
}
static inline int
pn_destroy(PFS_DESTROY_ARGS)
{
PFS_TRACE(("%s", pn->pn_name));
KASSERT(pn->pn_destroy != NULL, ("%s(): no callback", __func__));
pfs_assert_not_owned(pn);
return ((pn->pn_destroy)(PFS_DESTROY_ARGNAMES));
}
#endif