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[PATCH] uml: TLB operation batching

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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>
这个提交包含在：
Jeff Dike
2005-09-03 15:57:36 -07:00
提交者 Linus Torvalds
父节点 77fa5adcda
当前提交 c56004901f
共修改 8 个文件，包含 273 行新增和 166 行删除
下载 Patch 文件 下载 Diff 文件 展开所有文件 折叠所有文件

112
arch/um/kernel/skas/mem_user.c
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@@ -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)