Hi Michael,
I am currently cleaning up opencoded kmalloc with vmalloc fallback users
[1] and my current kvmalloc_node helper doesn't support GFP_REPEAT
because there are no users which would need it. At least that's what I
thought until I've encountered vhost_vsock_dev_open resp.
vhost_vsock_dev_open which are trying to use GFP_REPEAT for kmalloc.
23cc5a991c7a ("vhost-net: extend device allocation to vmalloc") explains
the motivation as follows:
"
As vmalloc() adds overhead on a critical network path, add __GFP_REPEAT
to kzalloc() flags to do this fallback only when really needed.
"I am wondering whether vmalloc adds more overhead than GFP_REPEAT which can get pretty costly for order-4 allocation which will be used here as struct vhost_net seems to be 36104 (at least in with my config). Have you ever measured the difference? So I am just trying to understand whether we should teach kvmalloc_node to understand GFP_REPEAT or there is no strong reason to keep the repeat flag. [1] http://lkml.kernel.org/r/20170102133700.1734-1-mho...@kernel.org -- Michal Hocko SUSE Labs _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
