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[PATCH] uml: TLB operation batching

Browse source 
This adds VM op batching to skas0.  Rather than having a context switch to and
from the userspace stub for each address space change, we write a number of
operations to the stub data page and invoke a different stub which loops over
them and executes them all in one go.

The operations are stored as [ system call number, arg1, arg2, ... ] tuples.

The set is terminated by a system call number of 0.  Single operations, i.e.
page faults, are handled in the old way, since that is slightly more
efficient.

For a kernel build, a minority (~1/4) of the operations are part of a set.
These sets averaged ~100 in length, so for this quarter, the context switching
overhead is greatly reduced.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Jeff Dike 2005-09-03 15:57:36 -07:00 committed by Linus Torvalds
parent 77fa5adcda
commit c56004901f
8 changed files with 273 additions and 166 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

22
arch/um/include/tlb.h
View file

@ -9,7 +9,7 @@
#include "um_mmu.h"
struct host_vm_op {
enum { MMAP, MUNMAP, MPROTECT } type;
enum { NONE, MMAP, MUNMAP, MPROTECT } type;
union {
struct {
unsigned long addr;
@ -38,24 +38,10 @@ extern void mprotect_kernel_vm(int w);
extern void force_flush_all(void);
extern void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
unsigned long end_addr, int force,
void (*do_ops)(union mm_context *,
struct host_vm_op *, int));
void *(*do_ops)(union mm_context *,
struct host_vm_op *, int, int,
void *));
extern int flush_tlb_kernel_range_common(unsigned long start,
unsigned long end);
extern int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
int r, int w, int x, struct host_vm_op *ops, int index,
int last_filled, union mm_context *mmu,
void (*do_ops)(union mm_context *, struct host_vm_op *,
int));
extern int add_munmap(unsigned long addr, unsigned long len,
struct host_vm_op *ops, int index, int last_filled,
union mm_context *mmu,
void (*do_ops)(union mm_context *, struct host_vm_op *,
int));
extern int add_mprotect(unsigned long addr, unsigned long len, int r, int w,
int x, struct host_vm_op *ops, int index,
int last_filled, union mm_context *mmu,
void (*do_ops)(union mm_context *, struct host_vm_op *,
int));
#endif

13
arch/um/kernel/skas/include/skas.h
View file

@ -24,11 +24,14 @@ extern void new_thread_proc(void *stack, void (*handler)(int sig));
extern void remove_sigstack(void);
extern void new_thread_handler(int sig);
extern void handle_syscall(union uml_pt_regs *regs);
extern int map(struct mm_id * mm_idp, unsigned long virt, unsigned long len,
int r, int w, int x, int phys_fd, unsigned long long offset);
extern int unmap(struct mm_id * mm_idp, void *addr, unsigned long len);
extern int protect(struct mm_id * mm_idp, unsigned long addr,
unsigned long len, int r, int w, int x);
extern void *map(struct mm_id * mm_idp, unsigned long virt,
unsigned long len, int r, int w, int x, int phys_fd,
unsigned long long offset, int done, void *data);
extern void *unmap(struct mm_id * mm_idp, void *addr,
unsigned long len, int done, void *data);
extern void *protect(struct mm_id * mm_idp, unsigned long addr,
unsigned long len, int r, int w, int x, int done,
void *data);
extern void user_signal(int sig, union uml_pt_regs *regs, int pid);
extern int new_mm(int from);
extern int start_userspace(unsigned long stub_stack);

112
arch/um/kernel/skas/mem_user.c
View file

@ -25,12 +25,14 @@
#include "sysdep/stub.h"
#include "skas.h"
extern unsigned long syscall_stub, __syscall_stub_start;
extern unsigned long syscall_stub, batch_syscall_stub, __syscall_stub_start;
extern void wait_stub_done(int pid, int sig, char * fname);
static long run_syscall_stub(struct mm_id * mm_idp, int syscall,
unsigned long *args)
int single_count = 0;
static long one_syscall_stub(struct mm_id * mm_idp, int syscall,
unsigned long *args)
{
int n, pid = mm_idp->u.pid;
unsigned long regs[MAX_REG_NR];
@ -49,18 +51,80 @@ static long run_syscall_stub(struct mm_id * mm_idp, int syscall,
regs[REGS_SYSCALL_ARG6] = args[5];
n = ptrace_setregs(pid, regs);
if(n < 0){
printk("run_syscall_stub : PTRACE_SETREGS failed, "
printk("one_syscall_stub : PTRACE_SETREGS failed, "
"errno = %d\n", n);
return(n);
}
wait_stub_done(pid, 0, "one_syscall_stub");
return(*((unsigned long *) mm_idp->stack));
}
int multi_count = 0;
int multi_op_count = 0;
static long many_syscall_stub(struct mm_id * mm_idp, int syscall,
unsigned long *args, int done, void **addr_out)
{
unsigned long regs[MAX_REG_NR], *stack;
int n, pid = mm_idp->u.pid;
stack = *addr_out;
if(stack == NULL)
stack = (unsigned long *) current_stub_stack();
*stack++ = syscall;
*stack++ = args[0];
*stack++ = args[1];
*stack++ = args[2];
*stack++ = args[3];
*stack++ = args[4];
*stack++ = args[5];
*stack = 0;
multi_op_count++;
if(!done && ((((unsigned long) stack) & ~PAGE_MASK) <
PAGE_SIZE - 8 * sizeof(long))){
*addr_out = stack;
return 0;
}
multi_count++;
get_safe_registers(regs);
regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
((unsigned long) &batch_syscall_stub -
(unsigned long) &__syscall_stub_start);
regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA;
n = ptrace_setregs(pid, regs);
if(n < 0){
printk("many_syscall_stub : PTRACE_SETREGS failed, "
"errno = %d\n", n);
return(n);
}
wait_stub_done(pid, 0, "run_syscall_stub");
wait_stub_done(pid, 0, "many_syscall_stub");
stack = (unsigned long *) mm_idp->stack;
return(*((unsigned long *) mm_idp->stack));
*addr_out = stack;
return(*stack);
}
int map(struct mm_id *mm_idp, unsigned long virt, unsigned long len,
int r, int w, int x, int phys_fd, unsigned long long offset)
static long run_syscall_stub(struct mm_id * mm_idp, int syscall,
unsigned long *args, void **addr, int done)
{
long res;
if((*addr == NULL) && done)
res = one_syscall_stub(mm_idp, syscall, args);
else res = many_syscall_stub(mm_idp, syscall, args, done, addr);
return res;
}
void *map(struct mm_id * mm_idp, unsigned long virt, unsigned long len,
int r, int w, int x, int phys_fd, unsigned long long offset,
int done, void *data)
{
int prot, n;
@ -70,6 +134,7 @@ int map(struct mm_id *mm_idp, unsigned long virt, unsigned long len,
if(proc_mm){
struct proc_mm_op map;
int fd = mm_idp->u.mm_fd;
map = ((struct proc_mm_op) { .op = MM_MMAP,
.u =
{ .mmap =
@ -91,21 +156,24 @@ int map(struct mm_id *mm_idp, unsigned long virt, unsigned long len,
MAP_SHARED | MAP_FIXED, phys_fd,
MMAP_OFFSET(offset) };
res = run_syscall_stub(mm_idp, STUB_MMAP_NR, args);
res = run_syscall_stub(mm_idp, STUB_MMAP_NR, args,
&data, done);
if((void *) res == MAP_FAILED)
printk("mmap stub failed, errno = %d\n", res);
}
return 0;
return data;
}
int unmap(struct mm_id *mm_idp, void *addr, unsigned long len)
void *unmap(struct mm_id * mm_idp, void *addr, unsigned long len, int done,
void *data)
{
int n;
if(proc_mm){
struct proc_mm_op unmap;
int fd = mm_idp->u.mm_fd;
unmap = ((struct proc_mm_op) { .op = MM_MUNMAP,
.u =
{ .munmap =
@ -113,28 +181,25 @@ int unmap(struct mm_id *mm_idp, void *addr, unsigned long len)
(unsigned long) addr,
.len = len } } } );
n = os_write_file(fd, &unmap, sizeof(unmap));
if(n != sizeof(unmap)) {
if(n < 0)
return(n);
else if(n > 0)
return(-EIO);
}
if(n != sizeof(unmap))
printk("unmap - proc_mm write returned %d\n", n);
}
else {
int res;
unsigned long args[] = { (unsigned long) addr, len, 0, 0, 0,
0 };
res = run_syscall_stub(mm_idp, __NR_munmap, args);
res = run_syscall_stub(mm_idp, __NR_munmap, args,
&data, done);
if(res < 0)
printk("munmap stub failed, errno = %d\n", res);
}
return(0);
return data;
}
int protect(struct mm_id *mm_idp, unsigned long addr, unsigned long len,
int r, int w, int x)
void *protect(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
int r, int w, int x, int done, void *data)
{
struct proc_mm_op protect;
int prot, n;
@ -160,12 +225,13 @@ int protect(struct mm_id *mm_idp, unsigned long addr, unsigned long len,
int res;
unsigned long args[] = { addr, len, prot, 0, 0, 0 };
res = run_syscall_stub(mm_idp, __NR_mprotect, args);
res = run_syscall_stub(mm_idp, __NR_mprotect, args,
&data, done);
if(res < 0)
panic("mprotect stub failed, errno = %d\n", res);
}
return(0);
return data;
}
void before_mem_skas(unsigned long unused)

23
arch/um/kernel/skas/tlb.c
View file

@ -18,7 +18,8 @@
#include "os.h"
#include "tlb.h"
static void do_ops(union mm_context *mmu, struct host_vm_op *ops, int last)
static void *do_ops(union mm_context *mmu, struct host_vm_op *ops, int last,
int finished, void *flush)
{
struct host_vm_op *op;
int i;
@ -27,24 +28,28 @@ static void do_ops(union mm_context *mmu, struct host_vm_op *ops, int last)
op = &ops[i];
switch(op->type){
case MMAP:
map(&mmu->skas.id, op->u.mmap.addr, op->u.mmap.len,
op->u.mmap.r, op->u.mmap.w, op->u.mmap.x,
op->u.mmap.fd, op->u.mmap.offset);
flush = map(&mmu->skas.id, op->u.mmap.addr,
op->u.mmap.len, op->u.mmap.r, op->u.mmap.w,
op->u.mmap.x, op->u.mmap.fd,
op->u.mmap.offset, finished, flush);
break;
case MUNMAP:
unmap(&mmu->skas.id, (void *) op->u.munmap.addr,
op->u.munmap.len);
flush = unmap(&mmu->skas.id, (void *) op->u.munmap.addr,
op->u.munmap.len, finished, flush);
break;
case MPROTECT:
protect(&mmu->skas.id, op->u.mprotect.addr,
op->u.mprotect.len, op->u.mprotect.r,
op->u.mprotect.w, op->u.mprotect.x);
flush = protect(&mmu->skas.id, op->u.mprotect.addr,
op->u.mprotect.len, op->u.mprotect.r,
op->u.mprotect.w, op->u.mprotect.x,
finished, flush);
break;
default:
printk("Unknown op type %d in do_ops\n", op->type);
break;
}
}
return flush;
}
extern int proc_mm;

226
arch/um/kernel/tlb.c
View file

@ -15,12 +15,116 @@
#include "mem_user.h"
#include "os.h"
static int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
int r, int w, int x, struct host_vm_op *ops, int index,
int last_filled, union mm_context *mmu, void **flush,
void *(*do_ops)(union mm_context *, struct host_vm_op *,
int, int, void *))
{
__u64 offset;
struct host_vm_op *last;
int fd;
fd = phys_mapping(phys, &offset);
if(index != -1){
last = &ops[index];
if((last->type == MMAP) &&
(last->u.mmap.addr + last->u.mmap.len == virt) &&
(last->u.mmap.r == r) && (last->u.mmap.w == w) &&
(last->u.mmap.x == x) && (last->u.mmap.fd == fd) &&
(last->u.mmap.offset + last->u.mmap.len == offset)){
last->u.mmap.len += len;
return index;
}
}
if(index == last_filled){
*flush = (*do_ops)(mmu, ops, last_filled, 0, *flush);
index = -1;
}
ops[++index] = ((struct host_vm_op) { .type = MMAP,
.u = { .mmap = {
.addr = virt,
.len = len,
.r = r,
.w = w,
.x = x,
.fd = fd,
.offset = offset }
} });
return index;
}
static int add_munmap(unsigned long addr, unsigned long len,
struct host_vm_op *ops, int index, int last_filled,
union mm_context *mmu, void **flush,
void *(*do_ops)(union mm_context *, struct host_vm_op *,
int, int, void *))
{
struct host_vm_op *last;
if(index != -1){
last = &ops[index];
if((last->type == MUNMAP) &&
(last->u.munmap.addr + last->u.mmap.len == addr)){
last->u.munmap.len += len;
return index;
}
}
if(index == last_filled){
*flush = (*do_ops)(mmu, ops, last_filled, 0, *flush);
index = -1;
}
ops[++index] = ((struct host_vm_op) { .type = MUNMAP,
.u = { .munmap = {
.addr = addr,
.len = len } } });
return index;
}
static int add_mprotect(unsigned long addr, unsigned long len, int r, int w,
int x, struct host_vm_op *ops, int index,
int last_filled, union mm_context *mmu, void **flush,
void *(*do_ops)(union mm_context *,
struct host_vm_op *, int, int, void *))
{
struct host_vm_op *last;
if(index != -1){
last = &ops[index];
if((last->type == MPROTECT) &&
(last->u.mprotect.addr + last->u.mprotect.len == addr) &&
(last->u.mprotect.r == r) && (last->u.mprotect.w == w) &&
(last->u.mprotect.x == x)){
last->u.mprotect.len += len;
return index;
}
}
if(index == last_filled){
*flush = (*do_ops)(mmu, ops, last_filled, 0, *flush);
index = -1;
}
ops[++index] = ((struct host_vm_op) { .type = MPROTECT,
.u = { .mprotect = {
.addr = addr,
.len = len,
.r = r,
.w = w,
.x = x } } });
return index;
}
#define ADD_ROUND(n, inc) (((n) + (inc)) & ~((inc) - 1))
void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
unsigned long end_addr, int force,
void (*do_ops)(union mm_context *, struct host_vm_op *,
int))
void *(*do_ops)(union mm_context *, struct host_vm_op *,
int, int, void *))
{
pgd_t *npgd;
pud_t *npud;
@ -29,11 +133,13 @@ void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
union mm_context *mmu = &mm->context;
unsigned long addr, end;
int r, w, x;
struct host_vm_op ops[16];
struct host_vm_op ops[1];
void *flush = NULL;
int op_index = -1, last_op = sizeof(ops) / sizeof(ops[0]) - 1;
if(mm == NULL) return;
ops[0].type = NONE;
for(addr = start_addr; addr < end_addr;){
npgd = pgd_offset(mm, addr);
if(!pgd_present(*npgd)){
@ -43,7 +149,7 @@ void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
if(force || pgd_newpage(*npgd)){
op_index = add_munmap(addr, end - addr, ops,
op_index, last_op, mmu,
do_ops);
&flush, do_ops);
pgd_mkuptodate(*npgd);
}
addr = end;
@ -58,7 +164,7 @@ void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
if(force || pud_newpage(*npud)){
op_index = add_munmap(addr, end - addr, ops,
op_index, last_op, mmu,
do_ops);
&flush, do_ops);
pud_mkuptodate(*npud);
}
addr = end;
@ -73,7 +179,7 @@ void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
if(force || pmd_newpage(*npmd)){
op_index = add_munmap(addr, end - addr, ops,
op_index, last_op, mmu,
do_ops);
&flush, do_ops);
pmd_mkuptodate(*npmd);
}
addr = end;
@ -96,20 +202,20 @@ void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
pte_val(*npte) & PAGE_MASK,
PAGE_SIZE, r, w, x, ops,
op_index, last_op, mmu,
do_ops);
&flush, do_ops);
else op_index = add_munmap(addr, PAGE_SIZE, ops,
op_index, last_op, mmu,
do_ops);
&flush, do_ops);
}
else if(pte_newprot(*npte))
op_index = add_mprotect(addr, PAGE_SIZE, r, w, x, ops,
op_index, last_op, mmu,
do_ops);
&flush, do_ops);
*npte = pte_mkuptodate(*npte);
addr += PAGE_SIZE;
}
(*do_ops)(mmu, ops, op_index);
flush = (*do_ops)(mmu, ops, op_index, 1, flush);
}
int flush_tlb_kernel_range_common(unsigned long start, unsigned long end)
@ -226,106 +332,6 @@ pte_t *addr_pte(struct task_struct *task, unsigned long addr)
return(pte_offset_map(pmd, addr));
}
int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
int r, int w, int x, struct host_vm_op *ops, int index,
int last_filled, union mm_context *mmu,
void (*do_ops)(union mm_context *, struct host_vm_op *, int))
{
__u64 offset;
struct host_vm_op *last;
int fd;
fd = phys_mapping(phys, &offset);
if(index != -1){
last = &ops[index];
if((last->type == MMAP) &&
(last->u.mmap.addr + last->u.mmap.len == virt) &&
(last->u.mmap.r == r) && (last->u.mmap.w == w) &&
(last->u.mmap.x == x) && (last->u.mmap.fd == fd) &&
(last->u.mmap.offset + last->u.mmap.len == offset)){
last->u.mmap.len += len;
return(index);
}
}
if(index == last_filled){
(*do_ops)(mmu, ops, last_filled);
index = -1;
}
ops[++index] = ((struct host_vm_op) { .type = MMAP,
.u = { .mmap = {
.addr = virt,
.len = len,
.r = r,
.w = w,
.x = x,
.fd = fd,
.offset = offset }
} });
return(index);
}
int add_munmap(unsigned long addr, unsigned long len, struct host_vm_op *ops,
int index, int last_filled, union mm_context *mmu,
void (*do_ops)(union mm_context *, struct host_vm_op *, int))
{
struct host_vm_op *last;
if(index != -1){
last = &ops[index];
if((last->type == MUNMAP) &&
(last->u.munmap.addr + last->u.mmap.len == addr)){
last->u.munmap.len += len;
return(index);
}
}
if(index == last_filled){
(*do_ops)(mmu, ops, last_filled);
index = -1;
}
ops[++index] = ((struct host_vm_op) { .type = MUNMAP,
.u = { .munmap = {
.addr = addr,
.len = len } } });
return(index);
}
int add_mprotect(unsigned long addr, unsigned long len, int r, int w, int x,
struct host_vm_op *ops, int index, int last_filled,
union mm_context *mmu,
void (*do_ops)(union mm_context *, struct host_vm_op *, int))
{
struct host_vm_op *last;
if(index != -1){
last = &ops[index];
if((last->type == MPROTECT) &&
(last->u.mprotect.addr + last->u.mprotect.len == addr) &&
(last->u.mprotect.r == r) && (last->u.mprotect.w == w) &&
(last->u.mprotect.x == x)){
last->u.mprotect.len += len;
return(index);
}
}
if(index == last_filled){
(*do_ops)(mmu, ops, last_filled);
index = -1;
}
ops[++index] = ((struct host_vm_op) { .type = MPROTECT,
.u = { .mprotect = {
.addr = addr,
.len = len,
.r = r,
.w = w,
.x = x } } });
return(index);
}
void flush_tlb_page(struct vm_area_struct *vma, unsigned long address)
{
address &= PAGE_MASK;

5
arch/um/kernel/tt/tlb.c
View file

@ -17,7 +17,8 @@
#include "os.h"
#include "tlb.h"
static void do_ops(union mm_context *mmu, struct host_vm_op *ops, int last)
static void *do_ops(union mm_context *mmu, struct host_vm_op *ops, int last,
int finished, void *flush)
{
struct host_vm_op *op;
int i;
@ -45,6 +46,8 @@ static void do_ops(union mm_context *mmu, struct host_vm_op *ops, int last)
break;
}
}
return NULL;
}
static void fix_range(struct mm_struct *mm, unsigned long start_addr,

17
arch/um/sys-i386/stub.S
View file

@ -6,3 +6,20 @@ syscall_stub:
int $0x80
mov %eax, UML_CONFIG_STUB_DATA
int3
.globl batch_syscall_stub
batch_syscall_stub:
mov $UML_CONFIG_STUB_DATA, %esp
again: pop %eax
cmpl $0, %eax
jz done
pop %ebx
pop %ecx
pop %edx
pop %esi
pop %edi
pop %ebp
int $0x80
mov %eax, UML_CONFIG_STUB_DATA
jmp again
done: int3

21
arch/um/sys-x86_64/stub.S
View file

@ -13,3 +13,24 @@ syscall_stub:
or %rcx, %rbx
movq %rax, (%rbx)
int3
.globl batch_syscall_stub
batch_syscall_stub:
movq $(UML_CONFIG_STUB_DATA >> 32), %rbx
salq $32, %rbx
movq $(UML_CONFIG_STUB_DATA & 0xffffffff), %rcx
or %rcx, %rbx
movq %rbx, %rsp
again: pop %rax
cmpq $0, %rax
jz done
pop %rdi
pop %rsi
pop %rdx
pop %r10
pop %r8
pop %r9
syscall
mov %rax, (%rbx)
jmp again
done: int3