freebsd-dev/sys/kern/kern_sharedpage.c

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2010, 2012 Konstantin Belousov <kib@FreeBSD.org>
* Copyright (c) 2015 The FreeBSD Foundation
* All rights reserved.
*
* Portions of this software were developed by Konstantin Belousov
* under sponsorship from the FreeBSD Foundation.
*
* 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.
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_vm.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
Switch the vm_object mutex to be a rwlock. This will enable in the future further optimizations where the vm_object lock will be held in read mode most of the time the page cache resident pool of pages are accessed for reading purposes. The change is mostly mechanical but few notes are reported: * The KPI changes as follow: - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK() - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK() - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK() - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED() (in order to avoid visibility of implementation details) - The read-mode operations are added: VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(), VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED() * The vm/vm_pager.h namespace pollution avoidance (forcing requiring sys/mutex.h in consumers directly to cater its inlining functions using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h consumers now must include also sys/rwlock.h. * zfs requires a quite convoluted fix to include FreeBSD rwlocks into the compat layer because the name clash between FreeBSD and solaris versions must be avoided. At this purpose zfs redefines the vm_object locking functions directly, isolating the FreeBSD components in specific compat stubs. The KPI results heavilly broken by this commit. Thirdy part ports must be updated accordingly (I can think off-hand of VirtualBox, for example). Sponsored by: EMC / Isilon storage division Reviewed by: jeff Reviewed by: pjd (ZFS specific review) Discussed with: alc Tested by: pho
2013-03-09 02:32:23 +00:00
#include <sys/rwlock.h>
#include <sys/sysent.h>
#include <sys/sysctl.h>
#include <sys/vdso.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
static struct sx shared_page_alloc_sx;
static vm_object_t shared_page_obj;
static int shared_page_free;
char *shared_page_mapping;
void
shared_page_write(int base, int size, const void *data)
{
bcopy(data, shared_page_mapping + base, size);
}
static int
shared_page_alloc_locked(int size, int align)
{
int res;
res = roundup(shared_page_free, align);
if (res + size >= IDX_TO_OFF(shared_page_obj->size))
res = -1;
else
shared_page_free = res + size;
return (res);
}
int
shared_page_alloc(int size, int align)
{
int res;
sx_xlock(&shared_page_alloc_sx);
res = shared_page_alloc_locked(size, align);
sx_xunlock(&shared_page_alloc_sx);
return (res);
}
int
shared_page_fill(int size, int align, const void *data)
{
int res;
sx_xlock(&shared_page_alloc_sx);
res = shared_page_alloc_locked(size, align);
if (res != -1)
shared_page_write(res, size, data);
sx_xunlock(&shared_page_alloc_sx);
return (res);
}
static void
shared_page_init(void *dummy __unused)
{
vm_page_t m;
vm_offset_t addr;
sx_init(&shared_page_alloc_sx, "shpsx");
shared_page_obj = vm_pager_allocate(OBJT_PHYS, 0, PAGE_SIZE,
VM_PROT_DEFAULT, 0, NULL);
Switch the vm_object mutex to be a rwlock. This will enable in the future further optimizations where the vm_object lock will be held in read mode most of the time the page cache resident pool of pages are accessed for reading purposes. The change is mostly mechanical but few notes are reported: * The KPI changes as follow: - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK() - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK() - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK() - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED() (in order to avoid visibility of implementation details) - The read-mode operations are added: VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(), VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED() * The vm/vm_pager.h namespace pollution avoidance (forcing requiring sys/mutex.h in consumers directly to cater its inlining functions using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h consumers now must include also sys/rwlock.h. * zfs requires a quite convoluted fix to include FreeBSD rwlocks into the compat layer because the name clash between FreeBSD and solaris versions must be avoided. At this purpose zfs redefines the vm_object locking functions directly, isolating the FreeBSD components in specific compat stubs. The KPI results heavilly broken by this commit. Thirdy part ports must be updated accordingly (I can think off-hand of VirtualBox, for example). Sponsored by: EMC / Isilon storage division Reviewed by: jeff Reviewed by: pjd (ZFS specific review) Discussed with: alc Tested by: pho
2013-03-09 02:32:23 +00:00
VM_OBJECT_WLOCK(shared_page_obj);
m = vm_page_grab(shared_page_obj, 0, VM_ALLOC_NOBUSY | VM_ALLOC_ZERO);
m->valid = VM_PAGE_BITS_ALL;
Switch the vm_object mutex to be a rwlock. This will enable in the future further optimizations where the vm_object lock will be held in read mode most of the time the page cache resident pool of pages are accessed for reading purposes. The change is mostly mechanical but few notes are reported: * The KPI changes as follow: - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK() - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK() - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK() - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED() (in order to avoid visibility of implementation details) - The read-mode operations are added: VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(), VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED() * The vm/vm_pager.h namespace pollution avoidance (forcing requiring sys/mutex.h in consumers directly to cater its inlining functions using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h consumers now must include also sys/rwlock.h. * zfs requires a quite convoluted fix to include FreeBSD rwlocks into the compat layer because the name clash between FreeBSD and solaris versions must be avoided. At this purpose zfs redefines the vm_object locking functions directly, isolating the FreeBSD components in specific compat stubs. The KPI results heavilly broken by this commit. Thirdy part ports must be updated accordingly (I can think off-hand of VirtualBox, for example). Sponsored by: EMC / Isilon storage division Reviewed by: jeff Reviewed by: pjd (ZFS specific review) Discussed with: alc Tested by: pho
2013-03-09 02:32:23 +00:00
VM_OBJECT_WUNLOCK(shared_page_obj);
addr = kva_alloc(PAGE_SIZE);
pmap_qenter(addr, &m, 1);
shared_page_mapping = (char *)addr;
}
SYSINIT(shp, SI_SUB_EXEC, SI_ORDER_FIRST, (sysinit_cfunc_t)shared_page_init,
NULL);
/*
* Push the timehands update to the shared page.
*
* The lockless update scheme is similar to the one used to update the
* in-kernel timehands, see sys/kern/kern_tc.c:tc_windup() (which
* calls us after the timehands are updated).
*/
static void
timehands_update(struct vdso_sv_tk *svtk)
{
struct vdso_timehands th;
struct vdso_timekeep *tk;
uint32_t enabled, idx;
enabled = tc_fill_vdso_timehands(&th);
th.th_gen = 0;
idx = svtk->sv_timekeep_curr;
if (++idx >= VDSO_TH_NUM)
idx = 0;
svtk->sv_timekeep_curr = idx;
if (++svtk->sv_timekeep_gen == 0)
svtk->sv_timekeep_gen = 1;
tk = (struct vdso_timekeep *)(shared_page_mapping +
svtk->sv_timekeep_off);
tk->tk_th[idx].th_gen = 0;
atomic_thread_fence_rel();
if (enabled)
tk->tk_th[idx] = th;
atomic_store_rel_32(&tk->tk_th[idx].th_gen, svtk->sv_timekeep_gen);
atomic_store_rel_32(&tk->tk_current, idx);
/*
* The ordering of the assignment to tk_enabled relative to
* the update of the vdso_timehands is not important.
*/
tk->tk_enabled = enabled;
}
#ifdef COMPAT_FREEBSD32
static void
timehands_update32(struct vdso_sv_tk *svtk)
{
struct vdso_timehands32 th;
struct vdso_timekeep32 *tk;
uint32_t enabled, idx;
enabled = tc_fill_vdso_timehands32(&th);
th.th_gen = 0;
idx = svtk->sv_timekeep_curr;
if (++idx >= VDSO_TH_NUM)
idx = 0;
svtk->sv_timekeep_curr = idx;
if (++svtk->sv_timekeep_gen == 0)
svtk->sv_timekeep_gen = 1;
tk = (struct vdso_timekeep32 *)(shared_page_mapping +
svtk->sv_timekeep_off);
tk->tk_th[idx].th_gen = 0;
atomic_thread_fence_rel();
if (enabled)
tk->tk_th[idx] = th;
atomic_store_rel_32(&tk->tk_th[idx].th_gen, svtk->sv_timekeep_gen);
atomic_store_rel_32(&tk->tk_current, idx);
tk->tk_enabled = enabled;
}
#endif
/*
* This is hackish, but easiest way to avoid creating list structures
* that needs to be iterated over from the hardclock interrupt
* context.
*/
static struct vdso_sv_tk *host_svtk;
#ifdef COMPAT_FREEBSD32
static struct vdso_sv_tk *compat32_svtk;
#endif
void
timekeep_push_vdso(void)
{
if (host_svtk != NULL)
timehands_update(host_svtk);
#ifdef COMPAT_FREEBSD32
if (compat32_svtk != NULL)
timehands_update32(compat32_svtk);
#endif
}
struct vdso_sv_tk *
alloc_sv_tk(void)
{
struct vdso_sv_tk *svtk;
int tk_base;
uint32_t tk_ver;
tk_ver = VDSO_TK_VER_CURR;
svtk = malloc(sizeof(struct vdso_sv_tk), M_TEMP, M_WAITOK | M_ZERO);
tk_base = shared_page_alloc(sizeof(struct vdso_timekeep) +
sizeof(struct vdso_timehands) * VDSO_TH_NUM, 16);
KASSERT(tk_base != -1, ("tk_base -1 for native"));
shared_page_write(tk_base + offsetof(struct vdso_timekeep, tk_ver),
sizeof(uint32_t), &tk_ver);
svtk->sv_timekeep_off = tk_base;
timekeep_push_vdso();
return (svtk);
}
#ifdef COMPAT_FREEBSD32
struct vdso_sv_tk *
alloc_sv_tk_compat32(void)
{
struct vdso_sv_tk *svtk;
int tk_base;
uint32_t tk_ver;
svtk = malloc(sizeof(struct vdso_sv_tk), M_TEMP, M_WAITOK | M_ZERO);
tk_ver = VDSO_TK_VER_CURR;
tk_base = shared_page_alloc(sizeof(struct vdso_timekeep32) +
sizeof(struct vdso_timehands32) * VDSO_TH_NUM, 16);
KASSERT(tk_base != -1, ("tk_base -1 for 32bit"));
shared_page_write(tk_base + offsetof(struct vdso_timekeep32,
tk_ver), sizeof(uint32_t), &tk_ver);
svtk->sv_timekeep_off = tk_base;
timekeep_push_vdso();
return (svtk);
}
#endif
void
exec_sysvec_init(void *param)
{
struct sysentvec *sv;
sv = (struct sysentvec *)param;
if ((sv->sv_flags & SV_SHP) == 0)
return;
sv->sv_shared_page_obj = shared_page_obj;
sv->sv_sigcode_base = sv->sv_shared_page_base +
shared_page_fill(*(sv->sv_szsigcode), 16, sv->sv_sigcode);
if ((sv->sv_flags & SV_ABI_MASK) != SV_ABI_FREEBSD)
return;
if ((sv->sv_flags & SV_TIMEKEEP) != 0) {
#ifdef COMPAT_FREEBSD32
if ((sv->sv_flags & SV_ILP32) != 0) {
KASSERT(compat32_svtk == NULL,
("Compat32 already registered"));
compat32_svtk = alloc_sv_tk_compat32();
sv->sv_timekeep_base = sv->sv_shared_page_base +
compat32_svtk->sv_timekeep_off;
} else {
#endif
KASSERT(host_svtk == NULL, ("Host already registered"));
host_svtk = alloc_sv_tk();
sv->sv_timekeep_base = sv->sv_shared_page_base +
host_svtk->sv_timekeep_off;
#ifdef COMPAT_FREEBSD32
}
#endif
}
}