On 06/17/2010 05:07 PM, Nathan Lynch wrote: > 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? Sounds reasonable. I originally left it out because I wasn't sure. In particular, my concern was whether a user may cause troubles by specifying this flag. Now I looked deeper, and I think it's safe. Note, however, it isn't enough to allow the flag, we also need to modify calc_map_flags_bits() to reintroduce MAP_NORESERVE for the flags argument to do_mmap_pgoff(). Otherwise it won't be restored at restart... No need to repost the patch. I'll do it. Oren. > > 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 */ _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
