On Thu, Sep 12, 2024 at 2:40 PM Morten Brørup <m...@smartsharesystems.com>
wrote:
>
> > +#define LCORE_BUFFER_SIZE (RTE_MAX_LCORE_VAR * RTE_MAX_LCORE)
>
> Considering hugepages...
>
> Lcore variables may be allocated before DPDK's memory allocator
> (rte_malloc()) is ready, so rte_malloc() cannot be used for lcore variables.
>
> And lcore variables are not usable (shared) for DPDK multi-process, so the
> lcore_buffer could be allocated through the O/S APIs as anonymous hugepages,
> instead of using rte_malloc().
>
> The alternative, using rte_malloc(), would disallow allocating lcore
> variables before DPDK's memory allocator has been initialized, which I think
> is too late.
I thought it is not. A lot of the subsystems are initialized after the
memory subsystem is initialized.
[1] example given in documentation. I thought, RTE_INIT needs to
replaced if the subsystem called after memory initialized (which is
the case for most of the libraries)
Trace library had a similar situation. It is managed like [2]
[1]
* struct foo_lcore_state {
* int a;
* long b;
* };
*
* static RTE_LCORE_VAR_HANDLE(struct foo_lcore_state, lcore_states);
*
* long foo_get_a_plus_b(void)
* {
* struct foo_lcore_state *state = RTE_LCORE_VAR_VALUE(lcore_states);
*
* return state->a + state->b;
* }
*
* RTE_INIT(rte_foo_init)
* {
* RTE_LCORE_VAR_ALLOC(lcore_states);
*
* struct foo_lcore_state *state;
* RTE_LCORE_VAR_FOREACH_VALUE(state, lcore_states) {
* (initialize 'state')
* }
*
* (other initialization)
* }
[2]
/* First attempt from huge page */
header = eal_malloc_no_trace(NULL, trace_mem_sz(trace->buff_len), 8);
if (header) {
trace->lcore_meta[count].area = TRACE_AREA_HUGEPAGE;
goto found;
}
/* Second attempt from heap */
header = malloc(trace_mem_sz(trace->buff_len));
if (header == NULL) {
trace_crit("trace mem malloc attempt failed");
header = NULL;
goto fail;
}
