[PATCH 7/9] UML - TLB operation batching
From: Jeff Dike
Date: Mon Aug 29 2005 - 15:18:53 EST
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@xxxxxxxxxxx>
Index: linux-2.6.12/arch/um/include/tlb.h
===================================================================
--- linux-2.6.12.orig/arch/um/include/tlb.h 2005-07-18 17:24:16.000000000 -0400
+++ linux-2.6.12/arch/um/include/tlb.h 2005-07-18 17:30:18.000000000 -0400
@@ -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 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
Index: linux-2.6.12/arch/um/kernel/skas/include/skas.h
===================================================================
--- linux-2.6.12.orig/arch/um/kernel/skas/include/skas.h 2005-07-18 17:24:16.000000000 -0400
+++ linux-2.6.12/arch/um/kernel/skas/include/skas.h 2005-07-18 20:05:40.000000000 -0400
@@ -24,11 +24,14 @@
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);
Index: linux-2.6.12/arch/um/kernel/skas/mem_user.c
===================================================================
--- linux-2.6.12.orig/arch/um/kernel/skas/mem_user.c 2005-07-18 17:24:16.000000000 -0400
+++ linux-2.6.12/arch/um/kernel/skas/mem_user.c 2005-07-18 17:30:18.000000000 -0400
@@ -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 @@
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;
+
+ *addr_out = stack;
+ return(*stack);
+}
+
+static long run_syscall_stub(struct mm_id * mm_idp, int syscall,
+ unsigned long *args, void **addr, int done)
+{
+ long res;
- return(*((unsigned long *) mm_idp->stack));
+ 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;
}
-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)
+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 @@
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 @@
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 @@
(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 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)
Index: linux-2.6.12/arch/um/kernel/skas/tlb.c
===================================================================
--- linux-2.6.12.orig/arch/um/kernel/skas/tlb.c 2005-07-18 17:24:16.000000000 -0400
+++ linux-2.6.12/arch/um/kernel/skas/tlb.c 2005-07-18 17:30:18.000000000 -0400
@@ -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 @@
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;
Index: linux-2.6.12/arch/um/kernel/tlb.c
===================================================================
--- linux-2.6.12.orig/arch/um/kernel/tlb.c 2005-07-18 17:24:17.000000000 -0400
+++ linux-2.6.12/arch/um/kernel/tlb.c 2005-07-18 20:05:57.000000000 -0400
@@ -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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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;
Index: linux-2.6.12/arch/um/kernel/tt/tlb.c
===================================================================
--- linux-2.6.12.orig/arch/um/kernel/tt/tlb.c 2005-07-18 17:24:16.000000000 -0400
+++ linux-2.6.12/arch/um/kernel/tt/tlb.c 2005-07-18 17:30:18.000000000 -0400
@@ -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 @@
break;
}
}
+
+ return NULL;
}
static void fix_range(struct mm_struct *mm, unsigned long start_addr,
Index: linux-2.6.12/arch/um/sys-i386/stub.S
===================================================================
--- linux-2.6.12.orig/arch/um/sys-i386/stub.S 2005-07-18 17:24:16.000000000 -0400
+++ linux-2.6.12/arch/um/sys-i386/stub.S 2005-07-18 17:30:18.000000000 -0400
@@ -6,3 +6,20 @@
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
Index: linux-2.6.12/arch/um/sys-x86_64/stub.S
===================================================================
--- linux-2.6.12.orig/arch/um/sys-x86_64/stub.S 2005-07-18 17:24:16.000000000 -0400
+++ linux-2.6.12/arch/um/sys-x86_64/stub.S 2005-07-18 17:30:18.000000000 -0400
@@ -13,3 +13,24 @@
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
-
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