u8 ev3_uart_set_msg_hdr(u8 type, const unsigned long size, u8 cmd)
{
	u8 size_code = (find_last_bit(&size, sizeof(unsigned long)) & 0x7) << 3;

	return (type & EV3_UART_MSG_TYPE_MASK) | size_code
		| (cmd & EV3_UART_MSG_CMD_MASK);
}
/* Checks if a mask spans multiple nodes
 *
 * @mask	: cpumask to check for multiple node span
 */
int xlp_span_multiple_nodes(const struct cpumask *mask)
{
    int l, f;
    f = cpumask_first(mask);
    l = find_last_bit(cpumask_bits(mask), NR_CPUS);
    if ((f/NLM_MAX_CPU_PER_NODE) != (l/NLM_MAX_CPU_PER_NODE)) {
        printk(KERN_DEBUG "Mask spans from cpu %#x to %#x. Spans across nodes are not supported\n", f, l);
        return -EINVAL;
    }
    return 0;
}
static int __init test_find_last_bit(const void *bitmap, unsigned long len)
{
	unsigned long l, cnt = 0;
	ktime_t time;

	time = ktime_get();
	do {
		cnt++;
		l = find_last_bit(bitmap, len);
		if (l >= len)
			break;
		len = l;
	} while (len);
	time = ktime_get() - time;
	pr_err("find_last_bit:      %18llu ns, %6ld iterations\n", time, cnt);

	return 0;
}
Exemple #4
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/*
 * nfs4_free_slot - free a slot and efficiently update slot table.
 *
 * freeing a slot is trivially done by clearing its respective bit
 * in the bitmap.
 * If the freed slotid equals highest_used_slotid we want to update it
 * so that the server would be able to size down the slot table if needed,
 * otherwise we know that the highest_used_slotid is still in use.
 * When updating highest_used_slotid there may be "holes" in the bitmap
 * so we need to scan down from highest_used_slotid to 0 looking for the now
 * highest slotid in use.
 * If none found, highest_used_slotid is set to NFS4_NO_SLOT.
 *
 * Must be called while holding tbl->slot_tbl_lock
 */
void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
{
	u32 slotid = slot->slot_nr;

	/* clear used bit in bitmap */
	__clear_bit(slotid, tbl->used_slots);

	/* update highest_used_slotid when it is freed */
	if (slotid == tbl->highest_used_slotid) {
		u32 new_max = find_last_bit(tbl->used_slots, slotid);
		if (new_max < slotid)
			tbl->highest_used_slotid = new_max;
		else {
			tbl->highest_used_slotid = NFS4_NO_SLOT;
			nfs4_slot_tbl_drain_complete(tbl);
		}
	}
	dprintk("%s: slotid %u highest_used_slotid %u\n", __func__,
		slotid, tbl->highest_used_slotid);
}
/* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
static void __init setup_nr_cpu_ids(void)
{
	nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
}
Exemple #6
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static void
host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
{
    HostMemoryBackend *backend = MEMORY_BACKEND(uc);
    HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
    Error *local_err = NULL;
    void *ptr;
    uint64_t sz;

    if (bc->alloc) {
        bc->alloc(backend, &local_err);
        if (local_err) {
            error_propagate(errp, local_err);
            return;
        }

        ptr = memory_region_get_ram_ptr(&backend->mr);
        sz = memory_region_size(&backend->mr);

        if (backend->merge) {
            qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
        }
        if (!backend->dump) {
            qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
        }
#ifdef CONFIG_NUMA
        unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
        /* lastbit == MAX_NODES means maxnode = 0 */
        unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
        /* ensure policy won't be ignored in case memory is preallocated
         * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
         * this doesn't catch hugepage case. */
        unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;

        /* check for invalid host-nodes and policies and give more verbose
         * error messages than mbind(). */
        if (maxnode && backend->policy == MPOL_DEFAULT) {
            error_setg(errp, "host-nodes must be empty for policy default,"
                       " or you should explicitly specify a policy other"
                       " than default");
            return;
        } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
            error_setg(errp, "host-nodes must be set for policy %s",
                       HostMemPolicy_lookup[backend->policy]);
            return;
        }

        /* We can have up to MAX_NODES nodes, but we need to pass maxnode+1
         * as argument to mbind() due to an old Linux bug (feature?) which
         * cuts off the last specified node. This means backend->host_nodes
         * must have MAX_NODES+1 bits available.
         */
        assert(sizeof(backend->host_nodes) >=
               BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
        assert(maxnode <= MAX_NODES);
        if (mbind(ptr, sz, backend->policy,
                  maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
            error_setg_errno(errp, errno,
                             "cannot bind memory to host NUMA nodes");
            return;
        }
#endif
        /* Preallocate memory after the NUMA policy has been instantiated.
         * This is necessary to guarantee memory is allocated with
         * specified NUMA policy in place.
         */
        if (backend->prealloc) {
            os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz);
        }
    }
}