[RFC] checkpoint: un-blacklist VM_NORESERVE

[Nathan Lynch <ntl-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>]

While a region mapped with MAP_NORESERVE may segv on a write in
low-memory conditions, reading it (as we do during checkpoint) is
fine.  Remove the VM_NORESERVE flag from CKPT_VMA_NOT_SUPPORTED.

---

Oren, what do you think about this?  I've tested this lightly with no
apparent problems; is there some reason I'm missing to not support
MAP_NORESERVE regions?

 include/linux/checkpoint.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
index 84bb7a9..f3e0d11 100644
--- a/include/linux/checkpoint.h
+++ b/include/linux/checkpoint.h
@@ -301,7 +301,7 @@ extern int restore_memory_contents(struct ckpt_ctx *ctx, struct inode *inode);
 
 #define CKPT_VMA_NOT_SUPPORTED						\
 	(VM_IO | VM_HUGETLB | VM_NONLINEAR | VM_PFNMAP |		\
-	 VM_RESERVED | VM_NORESERVE | VM_HUGETLB | VM_NONLINEAR |	\
+	 VM_RESERVED | VM_HUGETLB | VM_NONLINEAR |	\
 	 VM_MAPPED_COPY | VM_INSERTPAGE | VM_MIXEDMAP | VM_SAO)
 
 /* signals */
-- 
1.6.0.2