Re: [PATCH] eal/linux: lower log level on allocation attempt failure

[David Marchand <david.marchand@redhat.com>]

On Wed, Jun 26, 2024 at 5:00 PM Stephen Hemminger
<stephen@networkplumber.org> wrote:
>
> On Wed, 26 Jun 2024 16:51:42 +0200
> David Marchand <david.marchand@redhat.com> wrote:
>
> > On a ARM system with only 2MB hugepages configured, EAL emits an error
> > log with allocations larger than 512MB.
> >
> > Example with testpmd:
> > $ dpdk-testpmd --in-memory --no-pci --log-level=*:debug -- -i
> > ...
> > EAL: In-memory mode enabled, hugepages of size 33554432 bytes will be
> >       allocated anonymously
> > EAL: No free 32768 kB hugepages reported on node 0
> > EAL: In-memory mode enabled, hugepages of size 65536 bytes will be
> >       allocated anonymously
> > EAL: No free 64 kB hugepages reported on node 0
> > EAL: In-memory mode enabled, hugepages of size 1073741824 bytes will be
> >       allocated anonymously
> > EAL: No free 1048576 kB hugepages reported on node 0
> > ...
> > EAL: Detected memory type: socket_id:0 hugepage_sz:1073741824
> > EAL: Detected memory type: socket_id:0 hugepage_sz:33554432
> > EAL: Detected memory type: socket_id:0 hugepage_sz:2097152
> > EAL: Detected memory type: socket_id:0 hugepage_sz:65536
> > EAL: Creating 2 segment lists: n_segs:32 socket_id:0
> >       hugepage_sz:1073741824
> > ...
> > EAL: Creating 2 segment lists: n_segs:1024 socket_id:0
> >       hugepage_sz:33554432
> > ...
> > EAL: Creating 4 segment lists: n_segs:8192 socket_id:0
> >       hugepage_sz:2097152
> > ...
> > EAL: Creating 4 segment lists: n_segs:8192 socket_id:0
> >       hugepage_sz:65536
> > ...
> > EAL: Trying to obtain current memory policy.
> > EAL: Setting policy MPOL_PREFERRED for socket 0
> > EAL: alloc_seg(): mmap() failed: Cannot allocate memory
> > EAL: Ask a virtual area of 0x40000000 bytes
> > EAL: Virtual area found at 0x140000000 (size = 0x40000000)
> > EAL: attempted to allocate 2 segments, but only 0 were allocated
> > EAL: Restoring previous memory policy: 4
> > EAL: Trying to obtain current memory policy.
> > EAL: Setting policy MPOL_PREFERRED for socket 0
> > EAL: eal_memalloc_alloc_seg_bulk(): couldn't find suitable memseg_list
> > EAL: Restoring previous memory policy: 4
> > EAL: Trying to obtain current memory policy.
> > EAL: Setting policy MPOL_PREFERRED for socket 0
> > EAL: Restoring previous memory policy: 4
> > EAL: request: mp_malloc_sync
> > EAL: No shared files mode enabled, IPC is disabled
> > EAL: Heap on socket 0 was expanded by 1064MB
> > ...
> >
> > The reason is that the memzone allocation (~1GB large) would require
> > 17017 (32kB) segments. However, as displayed in the early logs, a 32kB
> > memory segment list can only host 8192 segments (controlled by the build
> > option RTE_MAX_MEMSEG_PER_LIST).
> >
> > This log message is misleading as there is no issue in the end: the
> > allocation succeeded with 2MB hugepages.
> >
> > Fixes: 582bed1e1d1d ("mem: support mapping hugepages at runtime")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: David Marchand <david.marchand@redhat.com>
> Acked-by: Stephen Hemminger <stephen@networkplumber.org>

Applied, thanks.


-- 
David Marchand