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restore: Bring trivial locker back

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Threads are better to be restored in serialized
way otherwise if some error happened an error
message will be screwed.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
This commit is contained in:
Cyrill Gorcunov
2011-11-17 00:59:08 +04:00
parent a095617253
commit 01f8f8f4d1
3 changed files with 35 additions and 1 deletions
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3
cr-restore.c
View File

@@ -1453,6 +1453,7 @@ static void sigreturn_restore(pid_t pstree_pid, pid_t pid)
task_args->pid = pid; task_args->pid = pid;
task_args->fd_core = fd_core; task_args->fd_core = fd_core;
task_args->fd_self_vmas = fd_self_vmas; task_args->fd_self_vmas = fd_self_vmas;
task_args->rst_lock = 0;
if (pstree_entry.nr_threads) { if (pstree_entry.nr_threads) {
int i; int i;
@@ -1479,6 +1480,8 @@ static void sigreturn_restore(pid_t pstree_pid, pid_t pid)
goto err; goto err;
} }
thread_args[i].rst_lock = &task_args->rst_lock;
pr_info("Thread %4d stack %8p heap %8p rt_sigframe %8p\n", pr_info("Thread %4d stack %8p heap %8p rt_sigframe %8p\n",
i, (long)thread_args[i].mem_zone.stack, i, (long)thread_args[i].mem_zone.stack,
thread_args[i].mem_zone.heap, thread_args[i].mem_zone.heap,

27
include/restorer.h
View File

@@ -54,6 +54,7 @@ struct thread_restore_args {
int pid; int pid;
int fd_core; int fd_core;
long *rst_lock;
} __aligned(sizeof(long)); } __aligned(sizeof(long));
struct task_restore_core_args { struct task_restore_core_args {
@@ -63,6 +64,7 @@ struct task_restore_core_args {
int fd_core; /* opened core file */ int fd_core; /* opened core file */
int fd_self_vmas; /* opened file with running VMAs to unmap */ int fd_self_vmas; /* opened file with running VMAs to unmap */
bool restore_threads; /* if to restore threads */ bool restore_threads; /* if to restore threads */
long rst_lock;
/* threads restoration */ /* threads restoration */
int nr_threads; /* number of threads */ int nr_threads; /* number of threads */
@@ -222,4 +224,29 @@ static void always_inline write_hex_n(unsigned long num)
sys_write(1, &c, 1); sys_write(1, &c, 1);
} }
static always_inline void rst_lock(long *v)
{
while (*v) {
asm volatile("lfence");
asm volatile("pause");
}
(*v)++;
asm volatile("sfence");
}
static always_inline void rst_unlock(long *v)
{
(*v)--;
asm volatile("sfence");
}
static always_inline void rst_wait_unlock(long *v)
{
while (*v) {
asm volatile("lfence");
asm volatile("pause");
}
}
#endif /* CR_RESTORER_H__ */ #endif /* CR_RESTORER_H__ */

6
restorer.c
View File

@@ -86,6 +86,8 @@ long restore_thread(long cmd, struct thread_restore_args *args)
goto core_restore_end; goto core_restore_end;
} }
rst_unlock(args->rst_lock);
new_sp = (long)rt_sigframe + 8; new_sp = (long)rt_sigframe + 8;
asm volatile( asm volatile(
"movq %0, %%rax \n" "movq %0, %%rax \n"
@@ -428,6 +430,8 @@ self_len_end:
if (thread_args[i].pid == args->pid) if (thread_args[i].pid == args->pid)
continue; continue;
rst_lock(&args->rst_lock);
new_sp = new_sp =
RESTORE_ALIGN_STACK((long)thread_args[i].mem_zone.stack, RESTORE_ALIGN_STACK((long)thread_args[i].mem_zone.stack,
sizeof(thread_args[i].mem_zone.stack)); sizeof(thread_args[i].mem_zone.stack));
@@ -478,7 +482,7 @@ self_len_end:
"g"(&thread_args[i]) "g"(&thread_args[i])
: "rax", "rdi", "rsi", "rdx", "r10", "memory"); : "rax", "rdi", "rsi", "rdx", "r10", "memory");
//r_wait_unlock(args->lock); rst_wait_unlock(&args->rst_lock);
} }
} }