David Hildenbrand david@redhat.com writes:
Thanks!
In general,
Acked-by: David Hildenbrand david@redhat.com
Two nits below, after staring at some other prctl implementations.
+#define PR_SET_MEMORY_MERGE 67 +#define PR_GET_MEMORY_MERGE 68 #endif /* _LINUX_PRCTL_H */ diff --git a/kernel/sys.c b/kernel/sys.c index 495cd87d9bf4..8c2e50edeb18 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -15,6 +15,7 @@ #include <linux/highuid.h> #include <linux/fs.h> #include <linux/kmod.h> +#include <linux/ksm.h> #include <linux/perf_event.h> #include <linux/resource.h> #include <linux/kernel.h> @@ -2661,6 +2662,30 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, case PR_SET_VMA: error = prctl_set_vma(arg2, arg3, arg4, arg5); break; +#ifdef CONFIG_KSM
- case PR_SET_MEMORY_MERGE:
Looking at some other code (PR_SET_NO_NEW_PRIVS/ PR_SET_THP_DISABLE) I wonder if we also want
if (arg3 || arg4 || arg5) return -EINVAL;
I added the above check. It requires that we always specify all parameters in the test programs. I also changed them accordingly.
For PR_GET_MEMORY_MERGE it looks good already.
if (mmap_write_lock_killable(me->mm))return -EINTR;if (arg2) {error = ksm_enable_merge_any(me->mm);} else {/** TODO: we might want disable KSM on all VMAs and* trigger unsharing to completely disable KSM.*/clear_bit(MMF_VM_MERGE_ANY, &me->mm->flags);error = 0;}mmap_write_unlock(me->mm);break;- case PR_GET_MEMORY_MERGE:
if (arg2 || arg3 || arg4 || arg5)return -EINVAL;error = !!test_bit(MMF_VM_MERGE_ANY, &me->mm->flags);break;+#endif default: error = -EINVAL; break;
[...]
+/**
- ksm_enable_merge_any - Add mm to mm ksm list and enable merging on all
compatible VMA's
- @mm: Pointer to mm
- Returns 0 on success, otherwise error code
- */
+int ksm_enable_merge_any(struct mm_struct *mm) +{
- int err;
- if (test_bit(MMF_VM_MERGE_ANY, &mm->flags))
return -EINVAL;I'm curious, why is enabling the prctl() supposed to fail if already enabled? (it would not fail if disabling and already disabled)
I changed that to not return an error in that case.
For example, PR_SET_THP_DISABLE/PR_SET_NO_NEW_PRIVS doesn't fail if already set.