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diff --git a/sys/compat/linuxkpi/common/include/asm/processor.h b/sys/compat/linuxkpi/common/include/asm/processor.h
--- a/sys/compat/linuxkpi/common/include/asm/processor.h
+++ b/sys/compat/linuxkpi/common/include/asm/processor.h
@@ -41,7 +41,7 @@
};
extern struct cpuinfo_x86 boot_cpu_data;
-extern struct cpuinfo_x86 __cpu_data[];
+extern struct cpuinfo_x86 *__cpu_data;
#define cpu_data(cpu) __cpu_data[cpu]
#endif
diff --git a/sys/compat/linuxkpi/common/src/linux_compat.c b/sys/compat/linuxkpi/common/src/linux_compat.c
--- a/sys/compat/linuxkpi/common/src/linux_compat.c
+++ b/sys/compat/linuxkpi/common/src/linux_compat.c
@@ -131,7 +131,8 @@
static struct vm_area_struct *linux_cdev_handle_find(void *handle);
cpumask_t cpu_online_mask;
-static cpumask_t static_single_cpu_mask[MAXCPU];
+static cpumask_t **static_single_cpu_mask;
+static cpumask_t *static_single_cpu_mask_lcs;
struct kobject linux_class_root;
struct device linux_root_device;
struct class linux_class_misc;
@@ -2569,17 +2570,19 @@
#if defined(__i386__) || defined(__amd64__)
bool linux_cpu_has_clflush;
struct cpuinfo_x86 boot_cpu_data;
-struct cpuinfo_x86 __cpu_data[MAXCPU];
+struct cpuinfo_x86 *__cpu_data;
#endif
cpumask_t *
lkpi_get_static_single_cpu_mask(int cpuid)
{
- KASSERT((cpuid >= 0 && cpuid < MAXCPU), ("%s: invalid cpuid %d\n",
+ KASSERT((cpuid >= 0 && cpuid <= mp_maxid), ("%s: invalid cpuid %d\n",
+ __func__, cpuid));
+ KASSERT(!CPU_ABSENT(cpuid), ("%s: cpu with cpuid %d is absent\n",
__func__, cpuid));
- return (&static_single_cpu_mask[cpuid]);
+ return (static_single_cpu_mask[cpuid]);
}
static void
@@ -2595,7 +2598,9 @@
boot_cpu_data.x86 = CPUID_TO_FAMILY(cpu_id);
boot_cpu_data.x86_model = CPUID_TO_MODEL(cpu_id);
- for (i = 0; i < MAXCPU; i++) {
+ __cpu_data = mallocarray(mp_maxid + 1,
+ sizeof(*__cpu_data), M_KMALLOC, M_WAITOK | M_ZERO);
+ CPU_FOREACH(i) {
__cpu_data[i].x86_clflush_size = cpu_clflush_line_size;
__cpu_data[i].x86_max_cores = mp_ncpus;
__cpu_data[i].x86 = CPUID_TO_FAMILY(cpu_id);
@@ -2630,13 +2635,92 @@
CPU_COPY(&all_cpus, &cpu_online_mask);
/*
* Generate a single-CPU cpumask_t for each CPU (possibly) in the system.
- * CPUs are indexed from 0..(MAXCPU-1). The entry for cpuid 0 will only
+ * CPUs are indexed from 0..(mp_maxid). The entry for cpuid 0 will only
* have itself in the cpumask, cupid 1 only itself on entry 1, and so on.
* This is used by cpumask_of() (and possibly others in the future) for,
* e.g., drivers to pass hints to irq_set_affinity_hint().
*/
- for (i = 0; i < MAXCPU; i++)
- CPU_SET(i, &static_single_cpu_mask[i]);
+ static_single_cpu_mask = mallocarray(mp_maxid + 1,
+ sizeof(static_single_cpu_mask), M_KMALLOC, M_WAITOK | M_ZERO);
+
+ /*
+ * When the number of CPUs reach a threshold, we start to save memory
+ * given the sets are static by overlapping those having their single
+ * bit set at same position in a bitset word. Asymptotically, this
+ * regular scheme is in O(n²) whereas the overlapping one is in O(n)
+ * only with n being the maximum number of CPUs, so the gain will become
+ * huge quite quickly. The threshold for 64-bit architectures is 128
+ * CPUs.
+ */
+ if (mp_ncpus < (2 * _BITSET_BITS)) {
+ cpumask_t *sscm_ptr;
+
+ /*
+ * This represents 'mp_ncpus * __bitset_words(CPU_SETSIZE) *
+ * (_BITSET_BITS / 8)' bytes (for comparison with the
+ * overlapping scheme).
+ */
+ static_single_cpu_mask_lcs = mallocarray(mp_ncpus,
+ sizeof(*static_single_cpu_mask_lcs),
+ M_KMALLOC, M_WAITOK | M_ZERO);
+
+ sscm_ptr = static_single_cpu_mask_lcs;
+ CPU_FOREACH(i) {
+ static_single_cpu_mask[i] = sscm_ptr++;
+ CPU_SET(i, static_single_cpu_mask[i]);
+ }
+ } else {
+ /* Pointer to a bitset word. */
+ __typeof(((cpuset_t *)NULL)->__bits[0]) *bwp;
+
+ /*
+ * Allocate memory for (static) spans of 'cpumask_t' ('cpuset_t'
+ * really) with a single bit set that can be reused for all
+ * single CPU masks by making them start at different offsets.
+ * We need '__bitset_words(CPU_SETSIZE) - 1' bitset words before
+ * the word having its single bit set, and the same amount
+ * after.
+ */
+ static_single_cpu_mask_lcs = mallocarray(_BITSET_BITS,
+ (2 * __bitset_words(CPU_SETSIZE) - 1) * (_BITSET_BITS / 8),
+ M_KMALLOC, M_WAITOK | M_ZERO);
+
+ /*
+ * We rely below on cpuset_t and the bitset generic
+ * implementation assigning words in the '__bits' array in the
+ * same order of bits (i.e., little-endian ordering, not to be
+ * confused with machine endianness, which concerns bits in
+ * words and other integers). This is an imperfect test, but it
+ * will detect a change to big-endian ordering.
+ */
+ _Static_assert(
+ __bitset_word(_BITSET_BITS + 1, _BITSET_BITS) == 1,
+ "Assumes a bitset implementation that is little-endian "
+ "on its words");
+
+ /* Initialize the single bit of each static span. */
+ bwp = (__typeof(bwp))static_single_cpu_mask_lcs +
+ (__bitset_words(CPU_SETSIZE) - 1);
+ for (i = 0; i < _BITSET_BITS; i++) {
+ CPU_SET(i, (cpuset_t *)bwp);
+ bwp += (2 * __bitset_words(CPU_SETSIZE) - 1);
+ }
+
+ /*
+ * Finally set all CPU masks to the proper word in their
+ * relevant span.
+ */
+ CPU_FOREACH(i) {
+ bwp = (__typeof(bwp))static_single_cpu_mask_lcs;
+ /* Find the non-zero word of the relevant span. */
+ bwp += (2 * __bitset_words(CPU_SETSIZE) - 1) *
+ (i % _BITSET_BITS) +
+ __bitset_words(CPU_SETSIZE) - 1;
+ /* Shift to find the CPU mask start. */
+ bwp -= (i / _BITSET_BITS);
+ static_single_cpu_mask[i] = (cpuset_t *)bwp;
+ }
+ }
strlcpy(init_uts_ns.name.release, osrelease, sizeof(init_uts_ns.name.release));
}
@@ -2649,6 +2733,12 @@
linux_kobject_kfree_name(&linux_root_device.kobj);
linux_kobject_kfree_name(&linux_class_misc.kobj);
+ free(static_single_cpu_mask_lcs, M_KMALLOC);
+ free(static_single_cpu_mask, M_KMALLOC);
+#if defined(__i386__) || defined(__amd64__)
+ free(__cpu_data, M_KMALLOC);
+#endif
+
mtx_destroy(&vmmaplock);
spin_lock_destroy(&pci_lock);
rw_destroy(&linux_vma_lock);

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