Just sending this out for a sanity check. This is on top of dave's
files_struct may_checkpoint patchset.
>From b696c872296616a03cd7f9791664259c0461bd24 Mon Sep 17 00:00:00 2001
From: Serge E. Hallyn <serue@xxxxxxxxxx>
Date: Mon, 2 Mar 2009 10:11:05 -0500
Subject: [PATCH 1/1] checkpoint: Note checkpointability of mm_struct (v2)
A task can't be checkpointed if:
1. it has VM_SHARED, VM_IO, etc, mappings
2. its mm is shared with a task outside its container.
1. is a temporary prohibition until support is implemented. 2. is
permanent, as we can't have references to the mm_struct outside the
checkpointed container. Well, the check may need to be be updated
at some point so that if the mm_struct is shared with a *child*
container that is allowed. But right now we don't support child
containers anyway.
The checkpointability flag is reset when a new mm is created. If
instead a task is created with CLONE_VM, then we unset the
may_checkpoint flag if any of the new-container flags
(CLONE_NEWNS etc) are also specified.
/proc/pid/status displays checkpointability of both files_struct
and task->mm. (should this be active_mm?)
Signed-off-by: Serge E. Hallyn <serue@xxxxxxxxxx>
---
checkpoint/ckpt_mem.c | 3 ---
fs/proc/array.c | 15 +++++++++++++++
include/linux/checkpoint.h | 23 +++++++++++++++++++++--
include/linux/mm_types.h | 3 +++
kernel/fork.c | 6 ++++++
mm/mmap.c | 9 +++++++++
6 files changed, 54 insertions(+), 5 deletions(-)
diff --git a/checkpoint/ckpt_mem.c b/checkpoint/ckpt_mem.c
index 4925ff2..b2531f7 100644
--- a/checkpoint/ckpt_mem.c
+++ b/checkpoint/ckpt_mem.c
@@ -448,9 +448,6 @@ static int cr_write_vma(struct cr_ctx *ctx, struct vm_area_struct *vma)
hh->vm_flags = vma->vm_flags;
hh->vm_pgoff = vma->vm_pgoff;
-#define CR_BAD_VM_FLAGS \
- (VM_SHARED | VM_MAYSHARE | VM_IO | VM_HUGETLB | VM_NONLINEAR)
-
if (vma->vm_flags & CR_BAD_VM_FLAGS) {
pr_warning("c/r: unsupported VMA %#lx\n", vma->vm_flags);
cr_hbuf_put(ctx, sizeof(*hh));
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 7e4877d..1d4e504 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -320,6 +320,20 @@ static inline void task_context_switch_counts(struct seq_file *m,
p->nivcsw);
}
+static inline void task_show_checkpointable(struct seq_file *m,
+ struct task_struct *p)
+{
+ if (test_bit(0, &p->mm->may_checkpoint))
+ seq_printf(m, "mm is checkpointable\n");
+ else
+ seq_printf(m, "mm is not checkpointable\n");
+
+ if (test_bit(0, &p->files->may_checkpoint))
+ seq_printf(m, "files are checkpointable\n");
+ else
+ seq_printf(m, "files are not checkpointable\n");
+}
+
int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
@@ -339,6 +353,7 @@ int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
task_show_regs(m, task);
#endif
task_context_switch_counts(m, task);
+ task_show_checkpointable(m, task);
return 0;
}
diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
index e10ab89..04c045c 100644
--- a/include/linux/checkpoint.h
+++ b/include/linux/checkpoint.h
@@ -13,6 +13,13 @@
#include <linux/path.h>
#include <linux/fs.h>
#include <linux/fdtable.h>
+#include <linux/mm_types.h>
+
+#define NEW_CONTAINER_FLAGS (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | \
+ CLONE_NEWUSER | CLONE_NEWPID | CLONE_NEWNET)
+
+#define CR_BAD_VM_FLAGS \
+ (VM_SHARED | VM_MAYSHARE | VM_IO | VM_HUGETLB | VM_NONLINEAR)
#ifdef CONFIG_CHECKPOINT_RESTART
@@ -103,14 +110,26 @@ extern int cr_read_files(struct cr_ctx *ctx);
#define pr_fmt(fmt) "[%d:c/r:%s] " fmt, task_pid_vnr(current), __func__
+static inline void __mm_deny_checkpointing(struct mm_struct *mm,
+ char *file, int line)
+{
+ if (!test_and_clear_bit(0, &mm->may_checkpoint))
+ return;
+ printk(KERN_INFO "process performed an (mm) action that can not be "
+ "checkpointed at: %s:%d\n", file, line);
+}
+#define mm_deny_checkpointing(f) \
+ __mm_deny_checkpointing(f, __FILE__, __LINE__)
+
+
static inline void __files_deny_checkpointing(struct files_struct *files,
char *file, int line)
{
if (!test_and_clear_bit(0, &files->may_checkpoint))
return;
- printk(KERN_INFO "process performed an action that can not be "
+ printk(KERN_INFO "process performed a (file) action that can not be "
"checkpointed at: %s:%d\n", file, line);
- WARN_ON(1);
+ //WARN_ON(1);
}
#define files_deny_checkpointing(f) \
__files_deny_checkpointing(f, __FILE__, __LINE__)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 92915e8..28c3c9f 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -274,6 +274,9 @@ struct mm_struct {
#ifdef CONFIG_MMU_NOTIFIER
struct mmu_notifier_mm *mmu_notifier_mm;
#endif
+#ifdef CONFIG_CHECKPOINT_RESTART
+ unsigned long may_checkpoint;
+#endif
};
#endif /* _LINUX_MM_TYPES_H */
diff --git a/kernel/fork.c b/kernel/fork.c
index a66fbde..525e309 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -60,6 +60,7 @@
#include <linux/tty.h>
#include <linux/proc_fs.h>
#include <linux/blkdev.h>
+#include <linux/checkpoint.h>
#include <trace/sched.h>
#include <asm/pgtable.h>
@@ -295,6 +296,8 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
-pages);
continue;
}
+ if (mpnt->vm_flags & CR_BAD_VM_FLAGS)
+ mm_deny_checkpointing(mm);
charge = 0;
if (mpnt->vm_flags & VM_ACCOUNT) {
unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT;
@@ -418,6 +421,7 @@ static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p)
{
atomic_set(&mm->mm_users, 1);
atomic_set(&mm->mm_count, 1);
+ set_bit(0, &mm->may_checkpoint);
init_rwsem(&mm->mmap_sem);
INIT_LIST_HEAD(&mm->mmlist);
mm->flags = (current->mm) ? current->mm->flags : default_dump_filter;
@@ -655,6 +659,8 @@ static int copy_mm(unsigned long clone_flags, struct task_struct * tsk)
if (clone_flags & CLONE_VM) {
atomic_inc(&oldmm->mm_users);
mm = oldmm;
+ if (clone_flags & NEW_CONTAINER_FLAGS)
+ mm_deny_checkpointing(mm);
goto good_mm;
}
diff --git a/mm/mmap.c b/mm/mmap.c
index fb4df8f..9472c83 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -27,6 +27,7 @@
#include <linux/mempolicy.h>
#include <linux/rmap.h>
#include <linux/mmu_notifier.h>
+#include <linux/checkpoint.h>
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
@@ -903,6 +904,14 @@ void vm_stat_account(struct mm_struct *mm, unsigned long flags,
mm->stack_vm += pages;
if (flags & (VM_RESERVED|VM_IO))
mm->reserved_vm += pages;
+ if (pages > 0 && flags & CR_BAD_VM_FLAGS) {
+ if (test_bit(0, &mm->may_checkpoint)) {
+ printk(KERN_INFO "pid %d flags %lu file %s\n",
+ current->pid, flags,
+ file->f_dentry->d_name.name);
+ }
+ mm_deny_checkpointing(mm);
+ }
}
#endif /* CONFIG_PROC_FS */
--
1.6.1
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