#include <linux/bitmap.h>
#include <linux/bootmem.h>
#include <linux/list.h>
+#include <linux/log2.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/mutex.h>
* Large page remapping first chunk setup helper
*/
#ifdef CONFIG_NEED_MULTIPLE_NODES
+
+/**
+ * pcpu_lpage_build_unit_map - build unit_map for large page remapping
+ * @static_size: the size of static percpu area in bytes
+ * @reserved_size: the size of reserved percpu area in bytes
+ * @dyn_sizep: in/out parameter for dynamic size, -1 for auto
+ * @unit_sizep: out parameter for unit size
+ * @unit_map: unit_map to be filled
+ * @cpu_distance_fn: callback to determine distance between cpus
+ *
+ * This function builds cpu -> unit map and determine other parameters
+ * considering needed percpu size, large page size and distances
+ * between CPUs in NUMA.
+ *
+ * CPUs which are of LOCAL_DISTANCE both ways are grouped together and
+ * may share units in the same large page. The returned configuration
+ * is guaranteed to have CPUs on different nodes on different large
+ * pages and >=75% usage of allocated virtual address space.
+ *
+ * RETURNS:
+ * On success, fills in @unit_map, sets *@dyn_sizep, *@unit_sizep and
+ * returns the number of units to be allocated. -errno on failure.
+ */
+int __init pcpu_lpage_build_unit_map(size_t static_size, size_t reserved_size,
+ ssize_t *dyn_sizep, size_t *unit_sizep,
+ size_t lpage_size, int *unit_map,
+ pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
+{
+ static int group_map[NR_CPUS] __initdata;
+ static int group_cnt[NR_CPUS] __initdata;
+ int group_cnt_max = 0;
+ size_t size_sum, min_unit_size, alloc_size;
+ int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */
+ int last_allocs;
+ unsigned int cpu, tcpu;
+ int group, unit;
+
+ /*
+ * Determine min_unit_size, alloc_size and max_upa such that
+ * alloc_size is multiple of lpage_size and is the smallest
+ * which can accomodate 4k aligned segments which are equal to
+ * or larger than min_unit_size.
+ */
+ size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, dyn_sizep);
+ min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
+
+ alloc_size = roundup(min_unit_size, lpage_size);
+ upa = alloc_size / min_unit_size;
+ while (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
+ upa--;
+ max_upa = upa;
+
+ /* group cpus according to their proximity */
+ for_each_possible_cpu(cpu) {
+ group = 0;
+ next_group:
+ for_each_possible_cpu(tcpu) {
+ if (cpu == tcpu)
+ break;
+ if (group_map[tcpu] == group &&
+ (cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE ||
+ cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) {
+ group++;
+ goto next_group;
+ }
+ }
+ group_map[cpu] = group;
+ group_cnt[group]++;
+ group_cnt_max = max(group_cnt_max, group_cnt[group]);
+ }
+
+ /*
+ * Expand unit size until address space usage goes over 75%
+ * and then as much as possible without using more address
+ * space.
+ */
+ last_allocs = INT_MAX;
+ for (upa = max_upa; upa; upa--) {
+ int allocs = 0, wasted = 0;
+
+ if (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
+ continue;
+
+ for (group = 0; group_cnt[group]; group++) {
+ int this_allocs = DIV_ROUND_UP(group_cnt[group], upa);
+ allocs += this_allocs;
+ wasted += this_allocs * upa - group_cnt[group];
+ }
+
+ /*
+ * Don't accept if wastage is over 25%. The
+ * greater-than comparison ensures upa==1 always
+ * passes the following check.
+ */
+ if (wasted > num_possible_cpus() / 3)
+ continue;
+
+ /* and then don't consume more memory */
+ if (allocs > last_allocs)
+ break;
+ last_allocs = allocs;
+ best_upa = upa;
+ }
+ *unit_sizep = alloc_size / best_upa;
+
+ /* assign units to cpus accordingly */
+ unit = 0;
+ for (group = 0; group_cnt[group]; group++) {
+ for_each_possible_cpu(cpu)
+ if (group_map[cpu] == group)
+ unit_map[cpu] = unit++;
+ unit = roundup(unit, best_upa);
+ }
+
+ return unit; /* unit contains aligned number of units */
+}
+
struct pcpul_ent {
- unsigned int cpu;
void *ptr;
+ void *map_addr;
};
static size_t pcpul_size;
-static size_t pcpul_unit_size;
+static size_t pcpul_lpage_size;
+static int pcpul_nr_lpages;
static struct pcpul_ent *pcpul_map;
-static struct vm_struct pcpul_vm;
+
+static bool __init pcpul_unit_to_cpu(int unit, const int *unit_map,
+ unsigned int *cpup)
+{
+ unsigned int cpu;
+
+ for_each_possible_cpu(cpu)
+ if (unit_map[cpu] == unit) {
+ if (cpup)
+ *cpup = cpu;
+ return true;
+ }
+
+ return false;
+}
+
+static void __init pcpul_lpage_dump_cfg(const char *lvl, size_t static_size,
+ size_t reserved_size, size_t dyn_size,
+ size_t unit_size, size_t lpage_size,
+ const int *unit_map, int nr_units)
+{
+ int width = 1, v = nr_units;
+ char empty_str[] = "--------";
+ int upl, lpl; /* units per lpage, lpage per line */
+ unsigned int cpu;
+ int lpage, unit;
+
+ while (v /= 10)
+ width++;
+ empty_str[min_t(int, width, sizeof(empty_str) - 1)] = '\0';
+
+ upl = max_t(int, lpage_size / unit_size, 1);
+ lpl = rounddown_pow_of_two(max_t(int, 60 / (upl * (width + 1) + 2), 1));
+
+ printk("%spcpu-lpage: sta/res/dyn=%zu/%zu/%zu unit=%zu lpage=%zu", lvl,
+ static_size, reserved_size, dyn_size, unit_size, lpage_size);
+
+ for (lpage = 0, unit = 0; unit < nr_units; unit++) {
+ if (!(unit % upl)) {
+ if (!(lpage++ % lpl)) {
+ printk("\n");
+ printk("%spcpu-lpage: ", lvl);
+ } else
+ printk("| ");
+ }
+ if (pcpul_unit_to_cpu(unit, unit_map, &cpu))
+ printk("%0*d ", width, cpu);
+ else
+ printk("%s ", empty_str);
+ }
+ printk("\n");
+}
/**
* pcpu_lpage_first_chunk - remap the first percpu chunk using large page
* @static_size: the size of static percpu area in bytes
* @reserved_size: the size of reserved percpu area in bytes
- * @dyn_size: free size for dynamic allocation in bytes, -1 for auto
+ * @dyn_size: free size for dynamic allocation in bytes
+ * @unit_size: unit size in bytes
* @lpage_size: the size of a large page
+ * @unit_map: cpu -> unit mapping
+ * @nr_units: the number of units
* @alloc_fn: function to allocate percpu lpage, always called with lpage_size
* @free_fn: function to free percpu memory, @size <= lpage_size
* @map_fn: function to map percpu lpage, always called with lpage_size
*
- * This allocator uses large page as unit. A large page is allocated
- * for each cpu and each is remapped into vmalloc area using large
- * page mapping. As large page can be quite large, only part of it is
- * used for the first chunk. Unused part is returned to the bootmem
- * allocator.
- *
- * So, the large pages are mapped twice - once to the physical mapping
- * and to the vmalloc area for the first percpu chunk. The double
- * mapping does add one more large TLB entry pressure but still is
- * much better than only using 4k mappings while still being NUMA
- * friendly.
+ * This allocator uses large page to build and map the first chunk.
+ * Unlike other helpers, the caller should always specify @dyn_size
+ * and @unit_size. These parameters along with @unit_map and
+ * @nr_units can be determined using pcpu_lpage_build_unit_map().
+ * This two stage initialization is to allow arch code to evaluate the
+ * parameters before committing to it.
+ *
+ * Large pages are allocated as directed by @unit_map and other
+ * parameters and mapped to vmalloc space. Unused holes are returned
+ * to the page allocator. Note that these holes end up being actively
+ * mapped twice - once to the physical mapping and to the vmalloc area
+ * for the first percpu chunk. Depending on architecture, this might
+ * cause problem when changing page attributes of the returned area.
+ * These double mapped areas can be detected using
+ * pcpu_lpage_remapped().
*
* RETURNS:
* The determined pcpu_unit_size which can be used to initialize
* percpu access on success, -errno on failure.
*/
ssize_t __init pcpu_lpage_first_chunk(size_t static_size, size_t reserved_size,
- ssize_t dyn_size, size_t lpage_size,
+ size_t dyn_size, size_t unit_size,
+ size_t lpage_size, const int *unit_map,
+ int nr_units,
pcpu_fc_alloc_fn_t alloc_fn,
pcpu_fc_free_fn_t free_fn,
pcpu_fc_map_fn_t map_fn)
{
- size_t size_sum;
+ static struct vm_struct vm;
+ size_t chunk_size = unit_size * nr_units;
size_t map_size;
unsigned int cpu;
- int i, j;
ssize_t ret;
+ int i, j, unit;
- /*
- * Currently supports only single page. Supporting multiple
- * pages won't be too difficult if it ever becomes necessary.
- */
- size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size);
+ pcpul_lpage_dump_cfg(KERN_DEBUG, static_size, reserved_size, dyn_size,
+ unit_size, lpage_size, unit_map, nr_units);
- pcpul_unit_size = lpage_size;
- pcpul_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
- if (pcpul_size > pcpul_unit_size) {
- pr_warning("PERCPU: static data is larger than large page, "
- "can't use large page\n");
- return -EINVAL;
- }
+ BUG_ON(chunk_size % lpage_size);
+
+ pcpul_size = static_size + reserved_size + dyn_size;
+ pcpul_lpage_size = lpage_size;
+ pcpul_nr_lpages = chunk_size / lpage_size;
/* allocate pointer array and alloc large pages */
- map_size = PFN_ALIGN(num_possible_cpus() * sizeof(pcpul_map[0]));
+ map_size = pcpul_nr_lpages * sizeof(pcpul_map[0]);
pcpul_map = alloc_bootmem(map_size);
- for_each_possible_cpu(cpu) {
+ /* allocate all pages */
+ for (i = 0; i < pcpul_nr_lpages; i++) {
+ size_t offset = i * lpage_size;
+ int first_unit = offset / unit_size;
+ int last_unit = (offset + lpage_size - 1) / unit_size;
void *ptr;
+ /* find out which cpu is mapped to this unit */
+ for (unit = first_unit; unit <= last_unit; unit++)
+ if (pcpul_unit_to_cpu(unit, unit_map, &cpu))
+ goto found;
+ continue;
+ found:
ptr = alloc_fn(cpu, lpage_size);
if (!ptr) {
pr_warning("PERCPU: failed to allocate large page "
goto enomem;
}
- /*
- * Only use pcpul_size bytes and give back the rest.
- *
- * Ingo: The lpage_size up-rounding bootmem is needed
- * to make sure the partial lpage is still fully RAM -
- * it's not well-specified to have a incompatible area
- * (unmapped RAM, device memory, etc.) in that hole.
- */
- free_fn(ptr + pcpul_size, lpage_size - pcpul_size);
-
- pcpul_map[cpu].cpu = cpu;
- pcpul_map[cpu].ptr = ptr;
+ pcpul_map[i].ptr = ptr;
+ }
- memcpy(ptr, __per_cpu_load, static_size);
+ /* return unused holes */
+ for (unit = 0; unit < nr_units; unit++) {
+ size_t start = unit * unit_size;
+ size_t end = start + unit_size;
+ size_t off, next;
+
+ /* don't free used part of occupied unit */
+ if (pcpul_unit_to_cpu(unit, unit_map, NULL))
+ start += pcpul_size;
+
+ /* unit can span more than one page, punch the holes */
+ for (off = start; off < end; off = next) {
+ void *ptr = pcpul_map[off / lpage_size].ptr;
+ next = min(roundup(off + 1, lpage_size), end);
+ if (ptr)
+ free_fn(ptr + off % lpage_size, next - off);
+ }
}
- /* allocate address and map */
- pcpul_vm.flags = VM_ALLOC;
- pcpul_vm.size = num_possible_cpus() * pcpul_unit_size;
- vm_area_register_early(&pcpul_vm, pcpul_unit_size);
+ /* allocate address, map and copy */
+ vm.flags = VM_ALLOC;
+ vm.size = chunk_size;
+ vm_area_register_early(&vm, unit_size);
+
+ for (i = 0; i < pcpul_nr_lpages; i++) {
+ if (!pcpul_map[i].ptr)
+ continue;
+ pcpul_map[i].map_addr = vm.addr + i * lpage_size;
+ map_fn(pcpul_map[i].ptr, lpage_size, pcpul_map[i].map_addr);
+ }
for_each_possible_cpu(cpu)
- map_fn(pcpul_map[cpu].ptr, pcpul_unit_size,
- pcpul_vm.addr + cpu * pcpul_unit_size);
+ memcpy(vm.addr + unit_map[cpu] * unit_size, __per_cpu_load,
+ static_size);
/* we're ready, commit */
pr_info("PERCPU: Remapped at %p with large pages, static data "
- "%zu bytes\n", pcpul_vm.addr, static_size);
+ "%zu bytes\n", vm.addr, static_size);
ret = pcpu_setup_first_chunk(static_size, reserved_size, dyn_size,
- pcpul_unit_size, pcpul_vm.addr, NULL);
-
- /* sort pcpul_map array for pcpu_lpage_remapped() */
- for (i = 0; i < num_possible_cpus() - 1; i++)
- for (j = i + 1; j < num_possible_cpus(); j++)
- if (pcpul_map[i].ptr > pcpul_map[j].ptr) {
- struct pcpul_ent tmp = pcpul_map[i];
- pcpul_map[i] = pcpul_map[j];
- pcpul_map[j] = tmp;
- }
+ unit_size, vm.addr, unit_map);
+
+ /*
+ * Sort pcpul_map array for pcpu_lpage_remapped(). Unmapped
+ * lpages are pushed to the end and trimmed.
+ */
+ for (i = 0; i < pcpul_nr_lpages - 1; i++)
+ for (j = i + 1; j < pcpul_nr_lpages; j++) {
+ struct pcpul_ent tmp;
+
+ if (!pcpul_map[j].ptr)
+ continue;
+ if (pcpul_map[i].ptr &&
+ pcpul_map[i].ptr < pcpul_map[j].ptr)
+ continue;
+
+ tmp = pcpul_map[i];
+ pcpul_map[i] = pcpul_map[j];
+ pcpul_map[j] = tmp;
+ }
+
+ while (pcpul_nr_lpages && !pcpul_map[pcpul_nr_lpages - 1].ptr)
+ pcpul_nr_lpages--;
return ret;
enomem:
- for_each_possible_cpu(cpu)
- if (pcpul_map[cpu].ptr)
- free_fn(pcpul_map[cpu].ptr, pcpul_size);
+ for (i = 0; i < pcpul_nr_lpages; i++)
+ if (pcpul_map[i].ptr)
+ free_fn(pcpul_map[i].ptr, lpage_size);
free_bootmem(__pa(pcpul_map), map_size);
return -ENOMEM;
}
*/
void *pcpu_lpage_remapped(void *kaddr)
{
- unsigned long unit_mask = pcpul_unit_size - 1;
- void *lpage_addr = (void *)((unsigned long)kaddr & ~unit_mask);
- unsigned long offset = (unsigned long)kaddr & unit_mask;
- int left = 0, right = num_possible_cpus() - 1;
+ unsigned long lpage_mask = pcpul_lpage_size - 1;
+ void *lpage_addr = (void *)((unsigned long)kaddr & ~lpage_mask);
+ unsigned long offset = (unsigned long)kaddr & lpage_mask;
+ int left = 0, right = pcpul_nr_lpages - 1;
int pos;
/* pcpul in use at all? */
left = pos + 1;
else if (pcpul_map[pos].ptr > lpage_addr)
right = pos - 1;
- else {
- /* it shouldn't be in the area for the first chunk */
- WARN_ON(offset < pcpul_size);
-
- return pcpul_vm.addr +
- pcpul_map[pos].cpu * pcpul_unit_size + offset;
- }
+ else
+ return pcpul_map[pos].map_addr + offset;
}
return NULL;
projects / users / hch / configfs.git / commitdiff