This patch adds a subsystem for recording a history of mm.
This patch records relation ship of each mm_structs and
preserve them in a tree. New record is added at fork()
and exec(). If all children disapperas at exit(), the record
will be removed.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
---
fs/exec.c | 1
include/linux/mm_types.h | 3 +
include/linux/oom.h | 14 ++++++++
kernel/fork.c | 3 +
mm/oom_kill.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 96 insertions(+)
Index: mm-work2/include/linux/oom.h
===================================================================
--- mm-work2.orig/include/linux/oom.h
+++ mm-work2/include/linux/oom.h
@@ -72,5 +72,19 @@ extern struct task_struct *find_lock_tas
extern int sysctl_oom_dump_tasks;
extern int sysctl_oom_kill_allocating_task;
extern int sysctl_panic_on_oom;
+
+#ifdef CONFIG_FORKBOMB_KILLER
+extern void track_mm_history(struct mm_struct *new, struct mm_struct *old);
+extern void delete_mm_history(struct mm_struct *mm);
+#else
+static inline void
+track_mm_history(struct mm_struct *new, struct mm_struct *old)
+{
+}
+static inline void delete_mm_history(struct mm_struct *mm)
+{
+}
+#endif
+
#endif /* __KERNEL__*/
#endif /* _INCLUDE_LINUX_OOM_H */
Index: mm-work2/mm/oom_kill.c
===================================================================
--- mm-work2.orig/mm/oom_kill.c
+++ mm-work2/mm/oom_kill.c
@@ -761,3 +761,78 @@ void pagefault_out_of_memory(void)
if (!test_thread_flag(TIF_MEMDIE))
schedule_timeout_uninterruptible(1);
}
+
+#ifdef CONFIG_FORKBOMB_KILLER
+
+struct mm_history {
+ spinlock_t lock;
+ struct mm_struct *mm;
+ struct mm_history *parent;
+ struct list_head siblings;
+ struct list_head children;
+ /* scores */
+ unsigned long start_time;
+ unsigned long score;
+ unsigned int family;
+ int need_to_kill;
+};
+
+struct mm_history init_hist = {
+ .parent = &init_hist,
+ .lock = __SPIN_LOCK_UNLOCKED(init_hist.lock),
+ .siblings = LIST_HEAD_INIT(init_hist.siblings),
+ .children = LIST_HEAD_INIT(init_hist.children),
+};
+
+void track_mm_history(struct mm_struct *new, struct mm_struct *parent)
+{
+ struct mm_history *hist, *phist;
+
+ hist = kmalloc(sizeof(*hist), GFP_KERNEL);
+ if (!hist)
+ return;
+ spin_lock_init(&hist->lock);
+ INIT_LIST_HEAD(&hist->children);
+ hist->mm = new;
+ hist->start_time = jiffies;
+ if (parent)
+ phist = parent->history;
+ else
+ phist = NULL;
+ if (!phist)
+ phist = &init_hist;
+ new->history = hist;
+ hist->parent = phist;
+ spin_lock(&phist->lock);
+ list_add_tail(&hist->siblings, &phist->children);
+ spin_unlock(&phist->lock);
+ return;
+}
+
+void delete_mm_history(struct mm_struct *mm)
+{
+ struct mm_history *hist, *phist;
+ bool nochild;
+
+ if (!mm->history)
+ return;
+ hist = mm->history;
+ spin_lock(&hist->lock);
+ nochild = list_empty(&hist->children);
+ mm->history = NULL;
+ hist->mm = NULL;
+ spin_unlock(&hist->lock);
+ /* delete if we have no child */
+ while (nochild && hist != &init_hist) {
+ phist = hist->parent;
+ spin_lock(&phist->lock);
+ list_del(&hist->siblings);
+ /* delete parent if it's dead & no more child other than me.*/
+ nochild = (phist->mm == NULL && list_empty(&phist->children));
+ spin_unlock(&phist->lock);
+ kfree(hist);
+ hist = phist;
+ }
+}
+
+#endif
Index: mm-work2/fs/exec.c
===================================================================
--- mm-work2.orig/fs/exec.c
+++ mm-work2/fs/exec.c
@@ -802,6 +802,7 @@ static int exec_mmap(struct mm_struct *m
}
task_unlock(tsk);
arch_pick_mmap_layout(mm);
+ track_mm_history(mm, old_mm);
if (old_mm) {
up_read(&old_mm->mmap_sem);
BUG_ON(active_mm != old_mm);
Index: mm-work2/kernel/fork.c
===================================================================
--- mm-work2.orig/kernel/fork.c
+++ mm-work2/kernel/fork.c
@@ -559,6 +559,7 @@ void mmput(struct mm_struct *mm)
ksm_exit(mm);
khugepaged_exit(mm); /* must run before exit_mmap */
exit_mmap(mm);
+ delete_mm_history(mm);
set_mm_exe_file(mm, NULL);
if (!list_empty(&mm->mmlist)) {
spin_lock(&mmlist_lock);
@@ -706,6 +707,8 @@ struct mm_struct *dup_mm(struct task_str
if (mm->binfmt && !try_module_get(mm->binfmt->module))
goto free_pt;
+ track_mm_history(mm, oldmm);
+
return mm;
free_pt:
Index: mm-work2/include/linux/mm_types.h
===================================================================
--- mm-work2.orig/include/linux/mm_types.h
+++ mm-work2/include/linux/mm_types.h
@@ -317,6 +317,9 @@ struct mm_struct {
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
pgtable_t pmd_huge_pte; /* protected by page_table_lock */
#endif
+#ifdef CONFIG_FORKBOMB_KILLER
+ struct mm_history *history;
+#endif
};
/* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxxx For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>