> > We do not have above code anymore:
> Sorry, I tried to say it in a simplified way and it caused a misunderstanding.
>
> <snip>
> static __always_inline int
> adjust_va_to_fit_type(struct rb_root *root, struct list_head *head,
> struct vmap_area *va, unsigned long nva_start_addr,
> unsigned long size)
>
> } else if (type == NE_FIT_TYPE) {
> /*
> * Split no edge of fit VA.
> *
> * | |
> * L V NVA V R
> * |---|-------|---|
> */
> lva = __this_cpu_xchg(ne_fit_preload_node, NULL);
> if (unlikely(!lva)) {
> /*
> * For percpu allocator we do not do any pre-allocation
> * and leave it as it is. The reason is it most likely
> * never ends up with NE_FIT_TYPE splitting. In case of
> * percpu allocations offsets and sizes are aligned to
> * fixed align request, i.e. RE_FIT_TYPE and FL_FIT_TYPE
> * are its main fitting cases.
> *
> * There are a few exceptions though, as an example it is
> * a first allocation (early boot up) when we have "one"
> * big free space that has to be split.
> *
> * Also we can hit this path in case of regular "vmap"
> * allocations, if "this" current CPU was not preloaded.
> * See the comment in alloc_vmap_area() why. If so, then
> * GFP_NOWAIT is used instead to get an extra object for
> * split purpose. That is rare and most time does not
> * occur.
> *
> * What happens if an allocation gets failed. Basically,
> * an "overflow" path is triggered to purge lazily freed
> * areas to free some memory, then, the "retry" path is
> * triggered to repeat one more time. See more details
> * in alloc_vmap_area() function.
> */
> lva = kmem_cache_alloc(vmap_area_cachep, GFP_NOWAIT);
> if (!lva)
> return -1;
> }
> <snip>
>
> Above allocation fail will meet WARN_ON_ONCE in the current kernel now.
> Should It be handled by alloc_vmap_area()?, as you described in a comment.
>
WARN_ONCE_ONCE() is a warning and not a panic, though your kernel config
considers it as a panic. Right, we go on retry path and we can remove
the warning only for GFP_NOWAIT-alloc-error. From the other hand we
should still have possibility to trigger a warning if an allocation
is not successful: no vmap space or low memory condition, thus no
physical memory.
>
> >
> > <snip>
> > commit 82dd23e84be3ead53b6d584d836f51852d1096e6
> > Author: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
> > Date: Thu Jul 11 20:58:57 2019 -0700
> >
> > mm/vmalloc.c: preload a CPU with one object for split purpose
> >
> > <snip>
> >
> > Which kernel are you testing?
>
> I'm currently testing v6.1.
> The panic occurred during power on/off test.
>
Could you please describe in more detail your test sequence, setup and HW?
--
Uladzislau Rezki
