Hi Shanmugasundaram, On Wed, Jun 09, 2021 at 01:46:35PM +0100, Bruce Richardson wrote: > On Wed, Jun 09, 2021 at 02:28:04PM +0200, David Marchand wrote: > > On Wed, Jun 9, 2021 at 2:02 PM Shanmugasundaram M <shansi...@gmail.com> > > wrote: > > > We are using 6Wind fastpath(fp-rte) which is using DPDK version 18.11.1. > > > We are seeing 65.5G(preallocated during startup) of virtual memory for > > > fp-rte on a 32GB machine, 10G of that was huge pages (5000 mappings of > > > 2M.) > > > > > > We found 4 strange anon (4K size) segments totaling 54.5G (16+16+16+6.5). > > > Note: we changed / customized memory CONFIG_RTE_MAX_MEMSEG_PER_LIST=24576 > > > and default value of CONFIG_RTE_MAX_MEMSEG_LISTS=64 used. > > > Kindly let us know > > > 1. Why are allocating 54.5 GB anonymous mapping > > > 2. When will we use it ? > > > > This is likely pre-reserved virtual memory from the DPDK allocator. > > This virtual memory won't probably never be used. > > > > There may not be actually any memory backing this, since DPDK will reserve > huge amounts of virtual address space without actually using it. So those > GB's you see in the virtual memory may be completely unused, the addresses > are just reserved to ensure that if memory does need to be mapped into the > process, we have an appropriate contiguous address block to put it in. > > > But you'd better ask 6WIND guys as they maintain their own DPDK downstream. > > > > Copying a few guys.
I agree with David and Bruce. This is probably related to virtual memory areas reserved by eal_get_virtual_area() (mmap of /dev/zero). Enabling EAL debug logs should show traces about it. If you need support (even on old 6WINDGate versions based on dpdk-18.11), please open a ticket at 6WIND support, we'll be happy to help. Regards, Olivier
