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-rw-r--r--include/uapi/linux/capability.h1
-rw-r--r--include/uapi/linux/prctl.h4
-rw-r--r--kernel/sys.c25
3 files changed, 30 insertions, 0 deletions
diff --git a/include/uapi/linux/capability.h b/include/uapi/linux/capability.h
index 240fdb9a60f6..272dc69fa080 100644
--- a/include/uapi/linux/capability.h
+++ b/include/uapi/linux/capability.h
@@ -301,6 +301,7 @@ struct vfs_ns_cap_data {
/* Allow more than 64hz interrupts from the real-time clock */
/* Override max number of consoles on console allocation */
/* Override max number of keymaps */
+/* Control memory reclaim behavior */
#define CAP_SYS_RESOURCE 24
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index 7da1b37b27aa..07b4f8131e36 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -234,4 +234,8 @@ struct prctl_mm_map {
#define PR_GET_TAGGED_ADDR_CTRL 56
# define PR_TAGGED_ADDR_ENABLE (1UL << 0)
+/* Control reclaim behavior when allocating memory */
+#define PR_SET_IO_FLUSHER 57
+#define PR_GET_IO_FLUSHER 58
+
#endif /* _LINUX_PRCTL_H */
diff --git a/kernel/sys.c b/kernel/sys.c
index a9331f101883..f9bc5c303e3f 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2261,6 +2261,8 @@ int __weak arch_prctl_spec_ctrl_set(struct task_struct *t, unsigned long which,
return -EINVAL;
}
+#define PR_IO_FLUSHER (PF_MEMALLOC_NOIO | PF_LESS_THROTTLE)
+
SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
unsigned long, arg4, unsigned long, arg5)
{
@@ -2488,6 +2490,29 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
return -EINVAL;
error = GET_TAGGED_ADDR_CTRL();
break;
+ case PR_SET_IO_FLUSHER:
+ if (!capable(CAP_SYS_RESOURCE))
+ return -EPERM;
+
+ if (arg3 || arg4 || arg5)
+ return -EINVAL;
+
+ if (arg2 == 1)
+ current->flags |= PR_IO_FLUSHER;
+ else if (!arg2)
+ current->flags &= ~PR_IO_FLUSHER;
+ else
+ return -EINVAL;
+ break;
+ case PR_GET_IO_FLUSHER:
+ if (!capable(CAP_SYS_RESOURCE))
+ return -EPERM;
+
+ if (arg2 || arg3 || arg4 || arg5)
+ return -EINVAL;
+
+ error = (current->flags & PR_IO_FLUSHER) == PR_IO_FLUSHER;
+ break;
default:
error = -EINVAL;
break;