--- /dev/null
+/*
+ * mm/percpu.c - percpu memory allocator
+ *
+ * Copyright (C) 2009 SUSE Linux Products GmbH
+ * Copyright (C) 2009 Tejun Heo <tj@kernel.org>
+ *
+ * This file is released under the GPLv2.
+ *
+ * This is percpu allocator which can handle both static and dynamic
+ * areas. Percpu areas are allocated in chunks. Each chunk is
+ * consisted of boot-time determined number of units and the first
+ * chunk is used for static percpu variables in the kernel image
+ * (special boot time alloc/init handling necessary as these areas
+ * need to be brought up before allocation services are running).
+ * Unit grows as necessary and all units grow or shrink in unison.
+ * When a chunk is filled up, another chunk is allocated.
+ *
+ * c0 c1 c2
+ * ------------------- ------------------- ------------
+ * | u0 | u1 | u2 | u3 | | u0 | u1 | u2 | u3 | | u0 | u1 | u
+ * ------------------- ...... ------------------- .... ------------
+ *
+ * Allocation is done in offset-size areas of single unit space. Ie,
+ * an area of 512 bytes at 6k in c1 occupies 512 bytes at 6k of c1:u0,
+ * c1:u1, c1:u2 and c1:u3. On UMA, units corresponds directly to
+ * cpus. On NUMA, the mapping can be non-linear and even sparse.
+ * Percpu access can be done by configuring percpu base registers
+ * according to cpu to unit mapping and pcpu_unit_size.
+ *
+ * There are usually many small percpu allocations many of them being
+ * as small as 4 bytes. The allocator organizes chunks into lists
+ * according to free size and tries to allocate from the fullest one.
+ * Each chunk keeps the maximum contiguous area size hint which is
+ * guaranteed to be equal to or larger than the maximum contiguous
+ * area in the chunk. This helps the allocator not to iterate the
+ * chunk maps unnecessarily.
+ *
+ * Allocation state in each chunk is kept using an array of integers
+ * on chunk->map. A positive value in the map represents a free
+ * region and negative allocated. Allocation inside a chunk is done
+ * by scanning this map sequentially and serving the first matching
+ * entry. This is mostly copied from the percpu_modalloc() allocator.
+ * Chunks can be determined from the address using the index field
+ * in the page struct. The index field contains a pointer to the chunk.
+ *
+ * To use this allocator, arch code should do the followings.
+ *
+ * - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate
+ * regular address to percpu pointer and back if they need to be
+ * different from the default
+ *
+ * - use pcpu_setup_first_chunk() during percpu area initialization to
+ * setup the first chunk containing the kernel static percpu area
+ */
+
+#include <linux/bitmap.h>
+#include <linux/bootmem.h>
+#include <linux/err.h>
+#include <linux/list.h>
+#include <linux/log2.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/percpu.h>
+#include <linux/pfn.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/vmalloc.h>
+#include <linux/workqueue.h>
+#include <linux/kmemleak.h>
+
+#include <asm/cacheflush.h>
+#include <asm/sections.h>
+#include <asm/tlbflush.h>
+#include <asm/io.h>
+
+#define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */
+#define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */
+#define PCPU_ATOMIC_MAP_MARGIN_LOW 32
+#define PCPU_ATOMIC_MAP_MARGIN_HIGH 64
+#define PCPU_EMPTY_POP_PAGES_LOW 2
+#define PCPU_EMPTY_POP_PAGES_HIGH 4
+
+#ifdef CONFIG_SMP
+/* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
+#ifndef __addr_to_pcpu_ptr
+#define __addr_to_pcpu_ptr(addr) \
+ (void __percpu *)((unsigned long)(addr) - \
+ (unsigned long)pcpu_base_addr + \
+ (unsigned long)__per_cpu_start)
+#endif
+#ifndef __pcpu_ptr_to_addr
+#define __pcpu_ptr_to_addr(ptr) \
+ (void __force *)((unsigned long)(ptr) + \
+ (unsigned long)pcpu_base_addr - \
+ (unsigned long)__per_cpu_start)
+#endif
+#else /* CONFIG_SMP */
+/* on UP, it's always identity mapped */
+#define __addr_to_pcpu_ptr(addr) (void __percpu *)(addr)
+#define __pcpu_ptr_to_addr(ptr) (void __force *)(ptr)
+#endif /* CONFIG_SMP */
+
+struct pcpu_chunk {
+ struct list_head list; /* linked to pcpu_slot lists */
+ int free_size; /* free bytes in the chunk */
+ int contig_hint; /* max contiguous size hint */
+ void *base_addr; /* base address of this chunk */
+
+ int map_used; /* # of map entries used before the sentry */
+ int map_alloc; /* # of map entries allocated */
+ int *map; /* allocation map */
+ struct work_struct map_extend_work;/* async ->map[] extension */
+
+ void *data; /* chunk data */
+ int first_free; /* no free below this */
+ bool immutable; /* no [de]population allowed */
+ int nr_populated; /* # of populated pages */
+ unsigned long populated[]; /* populated bitmap */
+};
+
+static int pcpu_unit_pages __read_mostly;
+static int pcpu_unit_size __read_mostly;
+static int pcpu_nr_units __read_mostly;
+static int pcpu_atom_size __read_mostly;
+static int pcpu_nr_slots __read_mostly;
+static size_t pcpu_chunk_struct_size __read_mostly;
+
+/* cpus with the lowest and highest unit addresses */
+static unsigned int pcpu_low_unit_cpu __read_mostly;
+static unsigned int pcpu_high_unit_cpu __read_mostly;
+
+/* the address of the first chunk which starts with the kernel static area */
+void *pcpu_base_addr __read_mostly;
+EXPORT_SYMBOL_GPL(pcpu_base_addr);
+
+static const int *pcpu_unit_map __read_mostly; /* cpu -> unit */
+const unsigned long *pcpu_unit_offsets __read_mostly; /* cpu -> unit offset */
+
+/* group information, used for vm allocation */
+static int pcpu_nr_groups __read_mostly;
+static const unsigned long *pcpu_group_offsets __read_mostly;
+static const size_t *pcpu_group_sizes __read_mostly;
+
+/*
+ * The first chunk which always exists. Note that unlike other
+ * chunks, this one can be allocated and mapped in several different
+ * ways and thus often doesn't live in the vmalloc area.
+ */
+static struct pcpu_chunk *pcpu_first_chunk;
+
+/*
+ * Optional reserved chunk. This chunk reserves part of the first
+ * chunk and serves it for reserved allocations. The amount of
+ * reserved offset is in pcpu_reserved_chunk_limit. When reserved
+ * area doesn't exist, the following variables contain NULL and 0
+ * respectively.
+ */
+static struct pcpu_chunk *pcpu_reserved_chunk;
+static int pcpu_reserved_chunk_limit;
+
+static DEFINE_SPINLOCK(pcpu_lock); /* all internal data structures */
+static DEFINE_MUTEX(pcpu_alloc_mutex); /* chunk create/destroy, [de]pop */
+
+static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */
+
+/*
+ * The number of empty populated pages, protected by pcpu_lock. The
+ * reserved chunk doesn't contribute to the count.
+ */
+static int pcpu_nr_empty_pop_pages;
+
+/*
+ * Balance work is used to populate or destroy chunks asynchronously. We
+ * try to keep the number of populated free pages between
+ * PCPU_EMPTY_POP_PAGES_LOW and HIGH for atomic allocations and at most one
+ * empty chunk.
+ */
+static void pcpu_balance_workfn(struct work_struct *work);
+static DECLARE_WORK(pcpu_balance_work, pcpu_balance_workfn);
+static bool pcpu_async_enabled __read_mostly;
+static bool pcpu_atomic_alloc_failed;
+
+static void pcpu_schedule_balance_work(void)
+{
+ if (pcpu_async_enabled)
+ schedule_work(&pcpu_balance_work);
+}
+
+static bool pcpu_addr_in_first_chunk(void *addr)
+{
+ void *first_start = pcpu_first_chunk->base_addr;
+
+ return addr >= first_start && addr < first_start + pcpu_unit_size;
+}
+
+static bool pcpu_addr_in_reserved_chunk(void *addr)
+{
+ void *first_start = pcpu_first_chunk->base_addr;
+
+ return addr >= first_start &&
+ addr < first_start + pcpu_reserved_chunk_limit;
+}
+
+static int __pcpu_size_to_slot(int size)
+{
+ int highbit = fls(size); /* size is in bytes */
+ return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1);
+}
+
+static int pcpu_size_to_slot(int size)
+{
+ if (size == pcpu_unit_size)
+ return pcpu_nr_slots - 1;
+ return __pcpu_size_to_slot(size);
+}
+
+static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
+{
+ if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int))
+ return 0;
+
+ return pcpu_size_to_slot(chunk->free_size);
+}
+
+/* set the pointer to a chunk in a page struct */
+static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu)
+{
+ page->index = (unsigned long)pcpu;
+}
+
+/* obtain pointer to a chunk from a page struct */
+static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
+{
+ return (struct pcpu_chunk *)page->index;
+}
+
+static int __maybe_unused pcpu_page_idx(unsigned int cpu, int page_idx)
+{
+ return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx;
+}
+
+static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
+ unsigned int cpu, int page_idx)
+{
+ return (unsigned long)chunk->base_addr + pcpu_unit_offsets[cpu] +
+ (page_idx << PAGE_SHIFT);
+}
+
+static void __maybe_unused pcpu_next_unpop(struct pcpu_chunk *chunk,
+ int *rs, int *re, int end)
+{
+ *rs = find_next_zero_bit(chunk->populated, end, *rs);
+ *re = find_next_bit(chunk->populated, end, *rs + 1);
+}
+
+static void __maybe_unused pcpu_next_pop(struct pcpu_chunk *chunk,
+ int *rs, int *re, int end)
+{
+ *rs = find_next_bit(chunk->populated, end, *rs);
+ *re = find_next_zero_bit(chunk->populated, end, *rs + 1);
+}
+
+/*
+ * (Un)populated page region iterators. Iterate over (un)populated
+ * page regions between @start and @end in @chunk. @rs and @re should
+ * be integer variables and will be set to start and end page index of
+ * the current region.
+ */
+#define pcpu_for_each_unpop_region(chunk, rs, re, start, end) \
+ for ((rs) = (start), pcpu_next_unpop((chunk), &(rs), &(re), (end)); \
+ (rs) < (re); \
+ (rs) = (re) + 1, pcpu_next_unpop((chunk), &(rs), &(re), (end)))
+
+#define pcpu_for_each_pop_region(chunk, rs, re, start, end) \
+ for ((rs) = (start), pcpu_next_pop((chunk), &(rs), &(re), (end)); \
+ (rs) < (re); \
+ (rs) = (re) + 1, pcpu_next_pop((chunk), &(rs), &(re), (end)))
+
+/**
+ * pcpu_mem_zalloc - allocate memory
+ * @size: bytes to allocate
+ *
+ * Allocate @size bytes. If @size is smaller than PAGE_SIZE,
+ * kzalloc() is used; otherwise, vzalloc() is used. The returned
+ * memory is always zeroed.
+ *
+ * CONTEXT:
+ * Does GFP_KERNEL allocation.
+ *
+ * RETURNS:
+ * Pointer to the allocated area on success, NULL on failure.
+ */
+static void *pcpu_mem_zalloc(size_t size)
+{
+ if (WARN_ON_ONCE(!slab_is_available()))
+ return NULL;
+
+ if (size <= PAGE_SIZE)
+ return kzalloc(size, GFP_KERNEL);
+ else
+ return vzalloc(size);
+}
+
+/**
+ * pcpu_mem_free - free memory
+ * @ptr: memory to free
+ * @size: size of the area
+ *
+ * Free @ptr. @ptr should have been allocated using pcpu_mem_zalloc().
+ */
+static void pcpu_mem_free(void *ptr, size_t size)
+{
+ if (size <= PAGE_SIZE)
+ kfree(ptr);
+ else
+ vfree(ptr);
+}
+
+/**
+ * pcpu_count_occupied_pages - count the number of pages an area occupies
+ * @chunk: chunk of interest
+ * @i: index of the area in question
+ *
+ * Count the number of pages chunk's @i'th area occupies. When the area's
+ * start and/or end address isn't aligned to page boundary, the straddled
+ * page is included in the count iff the rest of the page is free.
+ */
+static int pcpu_count_occupied_pages(struct pcpu_chunk *chunk, int i)
+{
+ int off = chunk->map[i] & ~1;
+ int end = chunk->map[i + 1] & ~1;
+
+ if (!PAGE_ALIGNED(off) && i > 0) {
+ int prev = chunk->map[i - 1];
+
+ if (!(prev & 1) && prev <= round_down(off, PAGE_SIZE))
+ off = round_down(off, PAGE_SIZE);
+ }
+
+ if (!PAGE_ALIGNED(end) && i + 1 < chunk->map_used) {
+ int next = chunk->map[i + 1];
+ int nend = chunk->map[i + 2] & ~1;
+
+ if (!(next & 1) && nend >= round_up(end, PAGE_SIZE))
+ end = round_up(end, PAGE_SIZE);
+ }
+
+ return max_t(int, PFN_DOWN(end) - PFN_UP(off), 0);
+}
+
+/**
+ * pcpu_chunk_relocate - put chunk in the appropriate chunk slot
+ * @chunk: chunk of interest
+ * @oslot: the previous slot it was on
+ *
+ * This function is called after an allocation or free changed @chunk.
+ * New slot according to the changed state is determined and @chunk is
+ * moved to the slot. Note that the reserved chunk is never put on
+ * chunk slots.
+ *
+ * CONTEXT:
+ * pcpu_lock.
+ */
+static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
+{
+ int nslot = pcpu_chunk_slot(chunk);
+
+ if (chunk != pcpu_reserved_chunk && oslot != nslot) {
+ if (oslot < nslot)
+ list_move(&chunk->list, &pcpu_slot[nslot]);
+ else
+ list_move_tail(&chunk->list, &pcpu_slot[nslot]);
+ }
+}
+
+/**
+ * pcpu_need_to_extend - determine whether chunk area map needs to be extended
+ * @chunk: chunk of interest
+ * @is_atomic: the allocation context
+ *
+ * Determine whether area map of @chunk needs to be extended. If
+ * @is_atomic, only the amount necessary for a new allocation is
+ * considered; however, async extension is scheduled if the left amount is
+ * low. If !@is_atomic, it aims for more empty space. Combined, this
+ * ensures that the map is likely to have enough available space to
+ * accomodate atomic allocations which can't extend maps directly.
+ *
+ * CONTEXT:
+ * pcpu_lock.
+ *
+ * RETURNS:
+ * New target map allocation length if extension is necessary, 0
+ * otherwise.
+ */
+static int pcpu_need_to_extend(struct pcpu_chunk *chunk, bool is_atomic)
+{
+ int margin, new_alloc;
+
+ if (is_atomic) {
+ margin = 3;
+
+ if (chunk->map_alloc <
+ chunk->map_used + PCPU_ATOMIC_MAP_MARGIN_LOW &&
+ pcpu_async_enabled)
+ schedule_work(&chunk->map_extend_work);
+ } else {
+ margin = PCPU_ATOMIC_MAP_MARGIN_HIGH;
+ }
+
+ if (chunk->map_alloc >= chunk->map_used + margin)
+ return 0;
+
+ new_alloc = PCPU_DFL_MAP_ALLOC;
+ while (new_alloc < chunk->map_used + margin)
+ new_alloc *= 2;
+
+ return new_alloc;
+}
+
+/**
+ * pcpu_extend_area_map - extend area map of a chunk
+ * @chunk: chunk of interest
+ * @new_alloc: new target allocation length of the area map
+ *
+ * Extend area map of @chunk to have @new_alloc entries.
+ *
+ * CONTEXT:
+ * Does GFP_KERNEL allocation. Grabs and releases pcpu_lock.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+static int pcpu_extend_area_map(struct pcpu_chunk *chunk, int new_alloc)
+{
+ int *old = NULL, *new = NULL;
+ size_t old_size = 0, new_size = new_alloc * sizeof(new[0]);
+ unsigned long flags;
+
+ new = pcpu_mem_zalloc(new_size);
+ if (!new)
+ return -ENOMEM;
+
+ /* acquire pcpu_lock and switch to new area map */
+ spin_lock_irqsave(&pcpu_lock, flags);
+
+ if (new_alloc <= chunk->map_alloc)
+ goto out_unlock;
+
+ old_size = chunk->map_alloc * sizeof(chunk->map[0]);
+ old = chunk->map;
+
+ memcpy(new, old, old_size);
+
+ chunk->map_alloc = new_alloc;
+ chunk->map = new;
+ new = NULL;
+
+out_unlock:
+ spin_unlock_irqrestore(&pcpu_lock, flags);
+
+ /*
+ * pcpu_mem_free() might end up calling vfree() which uses
+ * IRQ-unsafe lock and thus can't be called under pcpu_lock.
+ */
+ pcpu_mem_free(old, old_size);
+ pcpu_mem_free(new, new_size);
+
+ return 0;
+}
+
+static void pcpu_map_extend_workfn(struct work_struct *work)
+{
+ struct pcpu_chunk *chunk = container_of(work, struct pcpu_chunk,
+ map_extend_work);
+ int new_alloc;
+
+ spin_lock_irq(&pcpu_lock);
+ new_alloc = pcpu_need_to_extend(chunk, false);
+ spin_unlock_irq(&pcpu_lock);
+
+ if (new_alloc)
+ pcpu_extend_area_map(chunk, new_alloc);
+}
+
+/**
+ * pcpu_fit_in_area - try to fit the requested allocation in a candidate area
+ * @chunk: chunk the candidate area belongs to
+ * @off: the offset to the start of the candidate area
+ * @this_size: the size of the candidate area
+ * @size: the size of the target allocation
+ * @align: the alignment of the target allocation
+ * @pop_only: only allocate from already populated region
+ *
+ * We're trying to allocate @size bytes aligned at @align. @chunk's area
+ * at @off sized @this_size is a candidate. This function determines
+ * whether the target allocation fits in the candidate area and returns the
+ * number of bytes to pad after @off. If the target area doesn't fit, -1
+ * is returned.
+ *
+ * If @pop_only is %true, this function only considers the already
+ * populated part of the candidate area.
+ */
+static int pcpu_fit_in_area(struct pcpu_chunk *chunk, int off, int this_size,
+ int size, int align, bool pop_only)
+{
+ int cand_off = off;
+
+ while (true) {
+ int head = ALIGN(cand_off, align) - off;
+ int page_start, page_end, rs, re;
+
+ if (this_size < head + size)
+ return -1;
+
+ if (!pop_only)
+ return head;
+
+ /*
+ * If the first unpopulated page is beyond the end of the
+ * allocation, the whole allocation is populated;
+ * otherwise, retry from the end of the unpopulated area.
+ */
+ page_start = PFN_DOWN(head + off);
+ page_end = PFN_UP(head + off + size);
+
+ rs = page_start;
+ pcpu_next_unpop(chunk, &rs, &re, PFN_UP(off + this_size));
+ if (rs >= page_end)
+ return head;
+ cand_off = re * PAGE_SIZE;
+ }
+}
+
+/**
+ * pcpu_alloc_area - allocate area from a pcpu_chunk
+ * @chunk: chunk of interest
+ * @size: wanted size in bytes
+ * @align: wanted align
+ * @pop_only: allocate only from the populated area
+ * @occ_pages_p: out param for the number of pages the area occupies
+ *
+ * Try to allocate @size bytes area aligned at @align from @chunk.
+ * Note that this function only allocates the offset. It doesn't
+ * populate or map the area.
+ *
+ * @chunk->map must have at least two free slots.
+ *
+ * CONTEXT:
+ * pcpu_lock.
+ *
+ * RETURNS:
+ * Allocated offset in @chunk on success, -1 if no matching area is
+ * found.
+ */
+static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align,
+ bool pop_only, int *occ_pages_p)
+{
+ int oslot = pcpu_chunk_slot(chunk);
+ int max_contig = 0;
+ int i, off;
+ bool seen_free = false;
+ int *p;
+
+ for (i = chunk->first_free, p = chunk->map + i; i < chunk->map_used; i++, p++) {
+ int head, tail;
+ int this_size;
+
+ off = *p;
+ if (off & 1)
+ continue;
+
+ this_size = (p[1] & ~1) - off;
+
+ head = pcpu_fit_in_area(chunk, off, this_size, size, align,
+ pop_only);
+ if (head < 0) {
+ if (!seen_free) {
+ chunk->first_free = i;
+ seen_free = true;
+ }
+ max_contig = max(this_size, max_contig);
+ continue;
+ }
+
+ /*
+ * If head is small or the previous block is free,
+ * merge'em. Note that 'small' is defined as smaller
+ * than sizeof(int), which is very small but isn't too
+ * uncommon for percpu allocations.
+ */
+ if (head && (head < sizeof(int) || !(p[-1] & 1))) {
+ *p = off += head;
+ if (p[-1] & 1)
+ chunk->free_size -= head;
+ else
+ max_contig = max(*p - p[-1], max_contig);
+ this_size -= head;
+ head = 0;
+ }
+
+ /* if tail is small, just keep it around */
+ tail = this_size - head - size;
+ if (tail < sizeof(int)) {
+ tail = 0;
+ size = this_size - head;
+ }
+
+ /* split if warranted */
+ if (head || tail) {
+ int nr_extra = !!head + !!tail;
+
+ /* insert new subblocks */
+ memmove(p + nr_extra + 1, p + 1,
+ sizeof(chunk->map[0]) * (chunk->map_used - i));
+ chunk->map_used += nr_extra;
+
+ if (head) {
+ if (!seen_free) {
+ chunk->first_free = i;
+ seen_free = true;
+ }
+ *++p = off += head;
+ ++i;
+ max_contig = max(head, max_contig);
+ }
+ if (tail) {
+ p[1] = off + size;
+ max_contig = max(tail, max_contig);
+ }
+ }
+
+ if (!seen_free)
+ chunk->first_free = i + 1;
+
+ /* update hint and mark allocated */
+ if (i + 1 == chunk->map_used)
+ chunk->contig_hint = max_contig; /* fully scanned */
+ else
+ chunk->contig_hint = max(chunk->contig_hint,
+ max_contig);
+
+ chunk->free_size -= size;
+ *p |= 1;
+
+ *occ_pages_p = pcpu_count_occupied_pages(chunk, i);
+ pcpu_chunk_relocate(chunk, oslot);
+ return off;
+ }
+
+ chunk->contig_hint = max_contig; /* fully scanned */
+ pcpu_chunk_relocate(chunk, oslot);
+
+ /* tell the upper layer that this chunk has no matching area */
+ return -1;
+}
+
+/**
+ * pcpu_free_area - free area to a pcpu_chunk
+ * @chunk: chunk of interest
+ * @freeme: offset of area to free
+ * @occ_pages_p: out param for the number of pages the area occupies
+ *
+ * Free area starting from @freeme to @chunk. Note that this function
+ * only modifies the allocation map. It doesn't depopulate or unmap
+ * the area.
+ *
+ * CONTEXT:
+ * pcpu_lock.
+ */
+static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme,
+ int *occ_pages_p)
+{
+ int oslot = pcpu_chunk_slot(chunk);
+ int off = 0;
+ unsigned i, j;
+ int to_free = 0;
+ int *p;
+
+ freeme |= 1; /* we are searching for <given offset, in use> pair */
+
+ i = 0;
+ j = chunk->map_used;
+ while (i != j) {
+ unsigned k = (i + j) / 2;
+ off = chunk->map[k];
+ if (off < freeme)
+ i = k + 1;
+ else if (off > freeme)
+ j = k;
+ else
+ i = j = k;
+ }
+ BUG_ON(off != freeme);
+
+ if (i < chunk->first_free)
+ chunk->first_free = i;
+
+ p = chunk->map + i;
+ *p = off &= ~1;
+ chunk->free_size += (p[1] & ~1) - off;
+
+ *occ_pages_p = pcpu_count_occupied_pages(chunk, i);
+
+ /* merge with next? */
+ if (!(p[1] & 1))
+ to_free++;
+ /* merge with previous? */
+ if (i > 0 && !(p[-1] & 1)) {
+ to_free++;
+ i--;
+ p--;
+ }
+ if (to_free) {
+ chunk->map_used -= to_free;
+ memmove(p + 1, p + 1 + to_free,
+ (chunk->map_used - i) * sizeof(chunk->map[0]));
+ }
+
+ chunk->contig_hint = max(chunk->map[i + 1] - chunk->map[i] - 1, chunk->contig_hint);
+ pcpu_chunk_relocate(chunk, oslot);
+}
+
+static struct pcpu_chunk *pcpu_alloc_chunk(void)
+{
+ struct pcpu_chunk *chunk;
+
+ chunk = pcpu_mem_zalloc(pcpu_chunk_struct_size);
+ if (!chunk)
+ return NULL;
+
+ chunk->map = pcpu_mem_zalloc(PCPU_DFL_MAP_ALLOC *
+ sizeof(chunk->map[0]));
+ if (!chunk->map) {
+ pcpu_mem_free(chunk, pcpu_chunk_struct_size);
+ return NULL;
+ }
+
+ chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
+ chunk->map[0] = 0;
+ chunk->map[1] = pcpu_unit_size | 1;
+ chunk->map_used = 1;
+
+ INIT_LIST_HEAD(&chunk->list);
+ INIT_WORK(&chunk->map_extend_work, pcpu_map_extend_workfn);
+ chunk->free_size = pcpu_unit_size;
+ chunk->contig_hint = pcpu_unit_size;
+
+ return chunk;
+}
+
+static void pcpu_free_chunk(struct pcpu_chunk *chunk)
+{
+ if (!chunk)
+ return;
+ pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0]));
+ pcpu_mem_free(chunk, pcpu_chunk_struct_size);
+}
+
+/**
+ * pcpu_chunk_populated - post-population bookkeeping
+ * @chunk: pcpu_chunk which got populated
+ * @page_start: the start page
+ * @page_end: the end page
+ *
+ * Pages in [@page_start,@page_end) have been populated to @chunk. Update
+ * the bookkeeping information accordingly. Must be called after each
+ * successful population.
+ */
+static void pcpu_chunk_populated(struct pcpu_chunk *chunk,
+ int page_start, int page_end)
+{
+ int nr = page_end - page_start;
+
+ lockdep_assert_held(&pcpu_lock);
+
+ bitmap_set(chunk->populated, page_start, nr);
+ chunk->nr_populated += nr;
+ pcpu_nr_empty_pop_pages += nr;
+}
+
+/**
+ * pcpu_chunk_depopulated - post-depopulation bookkeeping
+ * @chunk: pcpu_chunk which got depopulated
+ * @page_start: the start page
+ * @page_end: the end page
+ *
+ * Pages in [@page_start,@page_end) have been depopulated from @chunk.
+ * Update the bookkeeping information accordingly. Must be called after
+ * each successful depopulation.
+ */
+static void pcpu_chunk_depopulated(struct pcpu_chunk *chunk,
+ int page_start, int page_end)
+{
+ int nr = page_end - page_start;
+
+ lockdep_assert_held(&pcpu_lock);
+
+ bitmap_clear(chunk->populated, page_start, nr);
+ chunk->nr_populated -= nr;
+ pcpu_nr_empty_pop_pages -= nr;
+}
+
+/*
+ * Chunk management implementation.
+ *
+ * To allow different implementations, chunk alloc/free and
+ * [de]population are implemented in a separate file which is pulled
+ * into this file and compiled together. The following functions
+ * should be implemented.
+ *
+ * pcpu_populate_chunk - populate the specified range of a chunk
+ * pcpu_depopulate_chunk - depopulate the specified range of a chunk
+ * pcpu_create_chunk - create a new chunk
+ * pcpu_destroy_chunk - destroy a chunk, always preceded by full depop
+ * pcpu_addr_to_page - translate address to physical address
+ * pcpu_verify_alloc_info - check alloc_info is acceptable during init
+ */
+static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size);
+static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size);
+static struct pcpu_chunk *pcpu_create_chunk(void);
+static void pcpu_destroy_chunk(struct pcpu_chunk *chunk);
+static struct page *pcpu_addr_to_page(void *addr);
+static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai);
+
+#ifdef CONFIG_NEED_PER_CPU_KM
+#include "percpu-km.c"
+#else
+#include "percpu-vm.c"
+#endif
+
+/**
+ * pcpu_chunk_addr_search - determine chunk containing specified address
+ * @addr: address for which the chunk needs to be determined.
+ *
+ * RETURNS:
+ * The address of the found chunk.
+ */
+static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
+{
+ /* is it in the first chunk? */
+ if (pcpu_addr_in_first_chunk(addr)) {
+ /* is it in the reserved area? */
+ if (pcpu_addr_in_reserved_chunk(addr))
+ return pcpu_reserved_chunk;
+ return pcpu_first_chunk;
+ }
+
+ /*
+ * The address is relative to unit0 which might be unused and
+ * thus unmapped. Offset the address to the unit space of the
+ * current processor before looking it up in the vmalloc
+ * space. Note that any possible cpu id can be used here, so
+ * there's no need to worry about preemption or cpu hotplug.
+ */
+ addr += pcpu_unit_offsets[raw_smp_processor_id()];
+ return pcpu_get_page_chunk(pcpu_addr_to_page(addr));
+}
+
+/**
+ * pcpu_alloc - the percpu allocator
+ * @size: size of area to allocate in bytes
+ * @align: alignment of area (max PAGE_SIZE)
+ * @reserved: allocate from the reserved chunk if available
+ * @gfp: allocation flags
+ *
+ * Allocate percpu area of @size bytes aligned at @align. If @gfp doesn't
+ * contain %GFP_KERNEL, the allocation is atomic.
+ *
+ * RETURNS:
+ * Percpu pointer to the allocated area on success, NULL on failure.
+ */
+static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved,
+ gfp_t gfp)
+{
+ static int warn_limit = 10;
+ struct pcpu_chunk *chunk;
+ const char *err;
+ bool is_atomic = (gfp & GFP_KERNEL) != GFP_KERNEL;
+ int occ_pages = 0;
+ int slot, off, new_alloc, cpu, ret;
+ unsigned long flags;
+ void __percpu *ptr;
+
+ /*
+ * We want the lowest bit of offset available for in-use/free
+ * indicator, so force >= 16bit alignment and make size even.
+ */
+ if (unlikely(align < 2))
+ align = 2;
+
+ size = ALIGN(size, 2);
+
+ if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
+ WARN(true, "illegal size (%zu) or align (%zu) for "
+ "percpu allocation\n", size, align);
+ return NULL;
+ }
+
+ spin_lock_irqsave(&pcpu_lock, flags);
+
+ /* serve reserved allocations from the reserved chunk if available */
+ if (reserved && pcpu_reserved_chunk) {
+ chunk = pcpu_reserved_chunk;
+
+ if (size > chunk->contig_hint) {
+ err = "alloc from reserved chunk failed";
+ goto fail_unlock;
+ }
+
+ while ((new_alloc = pcpu_need_to_extend(chunk, is_atomic))) {
+ spin_unlock_irqrestore(&pcpu_lock, flags);
+ if (is_atomic ||
+ pcpu_extend_area_map(chunk, new_alloc) < 0) {
+ err = "failed to extend area map of reserved chunk";
+ goto fail;
+ }
+ spin_lock_irqsave(&pcpu_lock, flags);
+ }
+
+ off = pcpu_alloc_area(chunk, size, align, is_atomic,
+ &occ_pages);
+ if (off >= 0)
+ goto area_found;
+
+ err = "alloc from reserved chunk failed";
+ goto fail_unlock;
+ }
+
+restart:
+ /* search through normal chunks */
+ for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) {
+ list_for_each_entry(chunk, &pcpu_slot[slot], list) {
+ if (size > chunk->contig_hint)
+ continue;
+
+ new_alloc = pcpu_need_to_extend(chunk, is_atomic);
+ if (new_alloc) {
+ if (is_atomic)
+ continue;
+ spin_unlock_irqrestore(&pcpu_lock, flags);
+ if (pcpu_extend_area_map(chunk,
+ new_alloc) < 0) {
+ err = "failed to extend area map";
+ goto fail;
+ }
+ spin_lock_irqsave(&pcpu_lock, flags);
+ /*
+ * pcpu_lock has been dropped, need to
+ * restart cpu_slot list walking.
+ */
+ goto restart;
+ }
+
+ off = pcpu_alloc_area(chunk, size, align, is_atomic,
+ &occ_pages);
+ if (off >= 0)
+ goto area_found;
+ }
+ }
+
+ spin_unlock_irqrestore(&pcpu_lock, flags);
+
+ /*
+ * No space left. Create a new chunk. We don't want multiple
+ * tasks to create chunks simultaneously. Serialize and create iff
+ * there's still no empty chunk after grabbing the mutex.
+ */
+ if (is_atomic)
+ goto fail;
+
+ mutex_lock(&pcpu_alloc_mutex);
+
+ if (list_empty(&pcpu_slot[pcpu_nr_slots - 1])) {
+ chunk = pcpu_create_chunk();
+ if (!chunk) {
+ mutex_unlock(&pcpu_alloc_mutex);
+ err = "failed to allocate new chunk";
+ goto fail;
+ }
+
+ spin_lock_irqsave(&pcpu_lock, flags);
+ pcpu_chunk_relocate(chunk, -1);
+ } else {
+ spin_lock_irqsave(&pcpu_lock, flags);
+ }
+
+ mutex_unlock(&pcpu_alloc_mutex);
+ goto restart;
+
+area_found:
+ spin_unlock_irqrestore(&pcpu_lock, flags);
+
+ /* populate if not all pages are already there */
+ if (!is_atomic) {
+ int page_start, page_end, rs, re;
+
+ mutex_lock(&pcpu_alloc_mutex);
+
+ page_start = PFN_DOWN(off);
+ page_end = PFN_UP(off + size);
+
+ pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
+ WARN_ON(chunk->immutable);
+
+ ret = pcpu_populate_chunk(chunk, rs, re);
+
+ spin_lock_irqsave(&pcpu_lock, flags);
+ if (ret) {
+ mutex_unlock(&pcpu_alloc_mutex);
+ pcpu_free_area(chunk, off, &occ_pages);
+ err = "failed to populate";
+ goto fail_unlock;
+ }
+ pcpu_chunk_populated(chunk, rs, re);
+ spin_unlock_irqrestore(&pcpu_lock, flags);
+ }
+
+ mutex_unlock(&pcpu_alloc_mutex);
+ }
+
+ if (chunk != pcpu_reserved_chunk)
+ pcpu_nr_empty_pop_pages -= occ_pages;
+
+ if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW)
+ pcpu_schedule_balance_work();
+
+ /* clear the areas and return address relative to base address */
+ for_each_possible_cpu(cpu)
+ memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
+
+ ptr = __addr_to_pcpu_ptr(chunk->base_addr + off);
+ kmemleak_alloc_percpu(ptr, size, gfp);
+ return ptr;
+
+fail_unlock:
+ spin_unlock_irqrestore(&pcpu_lock, flags);
+fail:
+ if (!is_atomic && warn_limit) {
+ pr_warning("PERCPU: allocation failed, size=%zu align=%zu atomic=%d, %s\n",
+ size, align, is_atomic, err);
+ dump_stack();
+ if (!--warn_limit)
+ pr_info("PERCPU: limit reached, disable warning\n");
+ }
+ if (is_atomic) {
+ /* see the flag handling in pcpu_blance_workfn() */
+ pcpu_atomic_alloc_failed = true;
+ pcpu_schedule_balance_work();
+ }
+ return NULL;
+}
+
+/**
+ * __alloc_percpu_gfp - allocate dynamic percpu area
+ * @size: size of area to allocate in bytes
+ * @align: alignment of area (max PAGE_SIZE)
+ * @gfp: allocation flags
+ *
+ * Allocate zero-filled percpu area of @size bytes aligned at @align. If
+ * @gfp doesn't contain %GFP_KERNEL, the allocation doesn't block and can
+ * be called from any context but is a lot more likely to fail.
+ *
+ * RETURNS:
+ * Percpu pointer to the allocated area on success, NULL on failure.
+ */
+void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp)
+{
+ return pcpu_alloc(size, align, false, gfp);
+}
+EXPORT_SYMBOL_GPL(__alloc_percpu_gfp);
+
+/**
+ * __alloc_percpu - allocate dynamic percpu area
+ * @size: size of area to allocate in bytes
+ * @align: alignment of area (max PAGE_SIZE)
+ *
+ * Equivalent to __alloc_percpu_gfp(size, align, %GFP_KERNEL).
+ */
+void __percpu *__alloc_percpu(size_t size, size_t align)
+{
+ return pcpu_alloc(size, align, false, GFP_KERNEL);
+}
+EXPORT_SYMBOL_GPL(__alloc_percpu);
+
+/**
+ * __alloc_reserved_percpu - allocate reserved percpu area
+ * @size: size of area to allocate in bytes
+ * @align: alignment of area (max PAGE_SIZE)
+ *
+ * Allocate zero-filled percpu area of @size bytes aligned at @align
+ * from reserved percpu area if arch has set it up; otherwise,
+ * allocation is served from the same dynamic area. Might sleep.
+ * Might trigger writeouts.
+ *
+ * CONTEXT:
+ * Does GFP_KERNEL allocation.
+ *
+ * RETURNS:
+ * Percpu pointer to the allocated area on success, NULL on failure.
+ */
+void __percpu *__alloc_reserved_percpu(size_t size, size_t align)
+{
+ return pcpu_alloc(size, align, true, GFP_KERNEL);
+}
+
+/**
+ * pcpu_balance_workfn - manage the amount of free chunks and populated pages
+ * @work: unused
+ *
+ * Reclaim all fully free chunks except for the first one.
+ */
+static void pcpu_balance_workfn(struct work_struct *work)
+{
+ LIST_HEAD(to_free);
+ struct list_head *free_head = &pcpu_slot[pcpu_nr_slots - 1];
+ struct pcpu_chunk *chunk, *next;
+ int slot, nr_to_pop, ret;
+
+ /*
+ * There's no reason to keep around multiple unused chunks and VM
+ * areas can be scarce. Destroy all free chunks except for one.
+ */
+ mutex_lock(&pcpu_alloc_mutex);
+ spin_lock_irq(&pcpu_lock);
+
+ list_for_each_entry_safe(chunk, next, free_head, list) {
+ WARN_ON(chunk->immutable);
+
+ /* spare the first one */
+ if (chunk == list_first_entry(free_head, struct pcpu_chunk, list))
+ continue;
+
+ list_move(&chunk->list, &to_free);
+ }
+
+ spin_unlock_irq(&pcpu_lock);
+
+ list_for_each_entry_safe(chunk, next, &to_free, list) {
+ int rs, re;
+
+ pcpu_for_each_pop_region(chunk, rs, re, 0, pcpu_unit_pages) {
+ pcpu_depopulate_chunk(chunk, rs, re);
+ spin_lock_irq(&pcpu_lock);
+ pcpu_chunk_depopulated(chunk, rs, re);
+ spin_unlock_irq(&pcpu_lock);
+ }
+ pcpu_destroy_chunk(chunk);
+ }
+
+ /*
+ * Ensure there are certain number of free populated pages for
+ * atomic allocs. Fill up from the most packed so that atomic
+ * allocs don't increase fragmentation. If atomic allocation
+ * failed previously, always populate the maximum amount. This
+ * should prevent atomic allocs larger than PAGE_SIZE from keeping
+ * failing indefinitely; however, large atomic allocs are not
+ * something we support properly and can be highly unreliable and
+ * inefficient.
+ */
+retry_pop:
+ if (pcpu_atomic_alloc_failed) {
+ nr_to_pop = PCPU_EMPTY_POP_PAGES_HIGH;
+ /* best effort anyway, don't worry about synchronization */
+ pcpu_atomic_alloc_failed = false;
+ } else {
+ nr_to_pop = clamp(PCPU_EMPTY_POP_PAGES_HIGH -
+ pcpu_nr_empty_pop_pages,
+ 0, PCPU_EMPTY_POP_PAGES_HIGH);
+ }
+
+ for (slot = pcpu_size_to_slot(PAGE_SIZE); slot < pcpu_nr_slots; slot++) {
+ int nr_unpop = 0, rs, re;
+
+ if (!nr_to_pop)
+ break;
+
+ spin_lock_irq(&pcpu_lock);
+ list_for_each_entry(chunk, &pcpu_slot[slot], list) {
+ nr_unpop = pcpu_unit_pages - chunk->nr_populated;
+ if (nr_unpop)
+ break;
+ }
+ spin_unlock_irq(&pcpu_lock);
+
+ if (!nr_unpop)
+ continue;
+
+ /* @chunk can't go away while pcpu_alloc_mutex is held */
+ pcpu_for_each_unpop_region(chunk, rs, re, 0, pcpu_unit_pages) {
+ int nr = min(re - rs, nr_to_pop);
+
+ ret = pcpu_populate_chunk(chunk, rs, rs + nr);
+ if (!ret) {
+ nr_to_pop -= nr;
+ spin_lock_irq(&pcpu_lock);
+ pcpu_chunk_populated(chunk, rs, rs + nr);
+ spin_unlock_irq(&pcpu_lock);
+ } else {
+ nr_to_pop = 0;
+ }
+
+ if (!nr_to_pop)
+ break;
+ }
+ }
+
+ if (nr_to_pop) {
+ /* ran out of chunks to populate, create a new one and retry */
+ chunk = pcpu_create_chunk();
+ if (chunk) {
+ spin_lock_irq(&pcpu_lock);
+ pcpu_chunk_relocate(chunk, -1);
+ spin_unlock_irq(&pcpu_lock);
+ goto retry_pop;
+ }
+ }
+
+ mutex_unlock(&pcpu_alloc_mutex);
+}
+
+/**
+ * free_percpu - free percpu area
+ * @ptr: pointer to area to free
+ *
+ * Free percpu area @ptr.
+ *
+ * CONTEXT:
+ * Can be called from atomic context.
+ */
+void free_percpu(void __percpu *ptr)
+{
+ void *addr;
+ struct pcpu_chunk *chunk;
+ unsigned long flags;
+ int off, occ_pages;
+
+ if (!ptr)
+ return;
+
+ kmemleak_free_percpu(ptr);
+
+ addr = __pcpu_ptr_to_addr(ptr);
+
+ spin_lock_irqsave(&pcpu_lock, flags);
+
+ chunk = pcpu_chunk_addr_search(addr);
+ off = addr - chunk->base_addr;
+
+ pcpu_free_area(chunk, off, &occ_pages);
+
+ if (chunk != pcpu_reserved_chunk)
+ pcpu_nr_empty_pop_pages += occ_pages;
+
+ /* if there are more than one fully free chunks, wake up grim reaper */
+ if (chunk->free_size == pcpu_unit_size) {
+ struct pcpu_chunk *pos;
+
+ list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list)
+ if (pos != chunk) {
+ pcpu_schedule_balance_work();
+ break;
+ }
+ }
+
+ spin_unlock_irqrestore(&pcpu_lock, flags);
+}
+EXPORT_SYMBOL_GPL(free_percpu);
+
+/**
+ * is_kernel_percpu_address - test whether address is from static percpu area
+ * @addr: address to test
+ *
+ * Test whether @addr belongs to in-kernel static percpu area. Module
+ * static percpu areas are not considered. For those, use
+ * is_module_percpu_address().
+ *
+ * RETURNS:
+ * %true if @addr is from in-kernel static percpu area, %false otherwise.
+ */
+bool is_kernel_percpu_address(unsigned long addr)
+{
+#ifdef CONFIG_SMP
+ const size_t static_size = __per_cpu_end - __per_cpu_start;
+ void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
+ unsigned int cpu;
+
+ for_each_possible_cpu(cpu) {
+ void *start = per_cpu_ptr(base, cpu);
+
+ if ((void *)addr >= start && (void *)addr < start + static_size)
+ return true;
+ }
+#endif
+ /* on UP, can't distinguish from other static vars, always false */
+ return false;
+}
+
+/**
+ * per_cpu_ptr_to_phys - convert translated percpu address to physical address
+ * @addr: the address to be converted to physical address
+ *
+ * Given @addr which is dereferenceable address obtained via one of
+ * percpu access macros, this function translates it into its physical
+ * address. The caller is responsible for ensuring @addr stays valid
+ * until this function finishes.
+ *
+ * percpu allocator has special setup for the first chunk, which currently
+ * supports either embedding in linear address space or vmalloc mapping,
+ * and, from the second one, the backing allocator (currently either vm or
+ * km) provides translation.
+ *
+ * The addr can be translated simply without checking if it falls into the
+ * first chunk. But the current code reflects better how percpu allocator
+ * actually works, and the verification can discover both bugs in percpu
+ * allocator itself and per_cpu_ptr_to_phys() callers. So we keep current
+ * code.
+ *
+ * RETURNS:
+ * The physical address for @addr.
+ */
+phys_addr_t per_cpu_ptr_to_phys(void *addr)
+{
+ void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
+ bool in_first_chunk = false;
+ unsigned long first_low, first_high;
+ unsigned int cpu;
+
+ /*
+ * The following test on unit_low/high isn't strictly
+ * necessary but will speed up lookups of addresses which
+ * aren't in the first chunk.
+ */
+ first_low = pcpu_chunk_addr(pcpu_first_chunk, pcpu_low_unit_cpu, 0);
+ first_high = pcpu_chunk_addr(pcpu_first_chunk, pcpu_high_unit_cpu,
+ pcpu_unit_pages);
+ if ((unsigned long)addr >= first_low &&
+ (unsigned long)addr < first_high) {
+ for_each_possible_cpu(cpu) {
+ void *start = per_cpu_ptr(base, cpu);
+
+ if (addr >= start && addr < start + pcpu_unit_size) {
+ in_first_chunk = true;
+ break;
+ }
+ }
+ }
+
+ if (in_first_chunk) {
+ if (!is_vmalloc_addr(addr))
+ return __pa(addr);
+ else
+ return page_to_phys(vmalloc_to_page(addr)) +
+ offset_in_page(addr);
+ } else
+ return page_to_phys(pcpu_addr_to_page(addr)) +
+ offset_in_page(addr);
+}
+
+/**
+ * pcpu_alloc_alloc_info - allocate percpu allocation info
+ * @nr_groups: the number of groups
+ * @nr_units: the number of units
+ *
+ * Allocate ai which is large enough for @nr_groups groups containing
+ * @nr_units units. The returned ai's groups[0].cpu_map points to the
+ * cpu_map array which is long enough for @nr_units and filled with
+ * NR_CPUS. It's the caller's responsibility to initialize cpu_map
+ * pointer of other groups.
+ *
+ * RETURNS:
+ * Pointer to the allocated pcpu_alloc_info on success, NULL on
+ * failure.
+ */
+struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
+ int nr_units)
+{
+ struct pcpu_alloc_info *ai;
+ size_t base_size, ai_size;
+ void *ptr;
+ int unit;
+
+ base_size = ALIGN(sizeof(*ai) + nr_groups * sizeof(ai->groups[0]),
+ __alignof__(ai->groups[0].cpu_map[0]));
+ ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]);
+
+ ptr = memblock_virt_alloc_nopanic(PFN_ALIGN(ai_size), 0);
+ if (!ptr)
+ return NULL;
+ ai = ptr;
+ ptr += base_size;
+
+ ai->groups[0].cpu_map = ptr;
+
+ for (unit = 0; unit < nr_units; unit++)
+ ai->groups[0].cpu_map[unit] = NR_CPUS;
+
+ ai->nr_groups = nr_groups;
+ ai->__ai_size = PFN_ALIGN(ai_size);
+
+ return ai;
+}
+
+/**
+ * pcpu_free_alloc_info - free percpu allocation info
+ * @ai: pcpu_alloc_info to free
+ *
+ * Free @ai which was allocated by pcpu_alloc_alloc_info().
+ */
+void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai)
+{
+ memblock_free_early(__pa(ai), ai->__ai_size);
+}
+
+/**
+ * pcpu_dump_alloc_info - print out information about pcpu_alloc_info
+ * @lvl: loglevel
+ * @ai: allocation info to dump
+ *
+ * Print out information about @ai using loglevel @lvl.
+ */
+static void pcpu_dump_alloc_info(const char *lvl,
+ const struct pcpu_alloc_info *ai)
+{
+ int group_width = 1, cpu_width = 1, width;
+ char empty_str[] = "--------";
+ int alloc = 0, alloc_end = 0;
+ int group, v;
+ int upa, apl; /* units per alloc, allocs per line */
+
+ v = ai->nr_groups;
+ while (v /= 10)
+ group_width++;
+
+ v = num_possible_cpus();
+ while (v /= 10)
+ cpu_width++;
+ empty_str[min_t(int, cpu_width, sizeof(empty_str) - 1)] = '\0';
+
+ upa = ai->alloc_size / ai->unit_size;
+ width = upa * (cpu_width + 1) + group_width + 3;
+ apl = rounddown_pow_of_two(max(60 / width, 1));
+
+ printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu",
+ lvl, ai->static_size, ai->reserved_size, ai->dyn_size,
+ ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size);
+
+ for (group = 0; group < ai->nr_groups; group++) {
+ const struct pcpu_group_info *gi = &ai->groups[group];
+ int unit = 0, unit_end = 0;
+
+ BUG_ON(gi->nr_units % upa);
+ for (alloc_end += gi->nr_units / upa;
+ alloc < alloc_end; alloc++) {
+ if (!(alloc % apl)) {
+ printk(KERN_CONT "\n");
+ printk("%spcpu-alloc: ", lvl);
+ }
+ printk(KERN_CONT "[%0*d] ", group_width, group);
+
+ for (unit_end += upa; unit < unit_end; unit++)
+ if (gi->cpu_map[unit] != NR_CPUS)
+ printk(KERN_CONT "%0*d ", cpu_width,
+ gi->cpu_map[unit]);
+ else
+ printk(KERN_CONT "%s ", empty_str);
+ }
+ }
+ printk(KERN_CONT "\n");
+}
+
+/**
+ * pcpu_setup_first_chunk - initialize the first percpu chunk
+ * @ai: pcpu_alloc_info describing how to percpu area is shaped
+ * @base_addr: mapped address
+ *
+ * Initialize the first percpu chunk which contains the kernel static
+ * perpcu area. This function is to be called from arch percpu area
+ * setup path.
+ *
+ * @ai contains all information necessary to initialize the first
+ * chunk and prime the dynamic percpu allocator.
+ *
+ * @ai->static_size is the size of static percpu area.
+ *
+ * @ai->reserved_size, if non-zero, specifies the amount of bytes to
+ * reserve after the static area in the first chunk. This reserves
+ * the first chunk such that it's available only through reserved
+ * percpu allocation. This is primarily used to serve module percpu
+ * static areas on architectures where the addressing model has
+ * limited offset range for symbol relocations to guarantee module
+ * percpu symbols fall inside the relocatable range.
+ *
+ * @ai->dyn_size determines the number of bytes available for dynamic
+ * allocation in the first chunk. The area between @ai->static_size +
+ * @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused.
+ *
+ * @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE
+ * and equal to or larger than @ai->static_size + @ai->reserved_size +
+ * @ai->dyn_size.
+ *
+ * @ai->atom_size is the allocation atom size and used as alignment
+ * for vm areas.
+ *
+ * @ai->alloc_size is the allocation size and always multiple of
+ * @ai->atom_size. This is larger than @ai->atom_size if
+ * @ai->unit_size is larger than @ai->atom_size.
+ *
+ * @ai->nr_groups and @ai->groups describe virtual memory layout of
+ * percpu areas. Units which should be colocated are put into the
+ * same group. Dynamic VM areas will be allocated according to these
+ * groupings. If @ai->nr_groups is zero, a single group containing
+ * all units is assumed.
+ *
+ * The caller should have mapped the first chunk at @base_addr and
+ * copied static data to each unit.
+ *
+ * If the first chunk ends up with both reserved and dynamic areas, it
+ * is served by two chunks - one to serve the core static and reserved
+ * areas and the other for the dynamic area. They share the same vm
+ * and page map but uses different area allocation map to stay away
+ * from each other. The latter chunk is circulated in the chunk slots
+ * and available for dynamic allocation like any other chunks.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
+ void *base_addr)
+{
+ static int smap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata;
+ static int dmap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata;
+ size_t dyn_size = ai->dyn_size;
+ size_t size_sum = ai->static_size + ai->reserved_size + dyn_size;
+ struct pcpu_chunk *schunk, *dchunk = NULL;
+ unsigned long *group_offsets;
+ size_t *group_sizes;
+ unsigned long *unit_off;
+ unsigned int cpu;
+ int *unit_map;
+ int group, unit, i;
+
+#define PCPU_SETUP_BUG_ON(cond) do { \
+ if (unlikely(cond)) { \
+ pr_emerg("PERCPU: failed to initialize, %s", #cond); \
+ pr_emerg("PERCPU: cpu_possible_mask=%*pb\n", \
+ cpumask_pr_args(cpu_possible_mask)); \
+ pcpu_dump_alloc_info(KERN_EMERG, ai); \
+ BUG(); \
+ } \
+} while (0)
+
+ /* sanity checks */
+ PCPU_SETUP_BUG_ON(ai->nr_groups <= 0);
+#ifdef CONFIG_SMP
+ PCPU_SETUP_BUG_ON(!ai->static_size);
+ PCPU_SETUP_BUG_ON((unsigned long)__per_cpu_start & ~PAGE_MASK);
+#endif
+ PCPU_SETUP_BUG_ON(!base_addr);
+ PCPU_SETUP_BUG_ON((unsigned long)base_addr & ~PAGE_MASK);
+ PCPU_SETUP_BUG_ON(ai->unit_size < size_sum);
+ PCPU_SETUP_BUG_ON(ai->unit_size & ~PAGE_MASK);
+ PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
+ PCPU_SETUP_BUG_ON(ai->dyn_size < PERCPU_DYNAMIC_EARLY_SIZE);
+ PCPU_SETUP_BUG_ON(pcpu_verify_alloc_info(ai) < 0);
+
+ /* process group information and build config tables accordingly */
+ group_offsets = memblock_virt_alloc(ai->nr_groups *
+ sizeof(group_offsets[0]), 0);
+ group_sizes = memblock_virt_alloc(ai->nr_groups *
+ sizeof(group_sizes[0]), 0);
+ unit_map = memblock_virt_alloc(nr_cpu_ids * sizeof(unit_map[0]), 0);
+ unit_off = memblock_virt_alloc(nr_cpu_ids * sizeof(unit_off[0]), 0);
+
+ for (cpu = 0; cpu < nr_cpu_ids; cpu++)
+ unit_map[cpu] = UINT_MAX;
+
+ pcpu_low_unit_cpu = NR_CPUS;
+ pcpu_high_unit_cpu = NR_CPUS;
+
+ for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
+ const struct pcpu_group_info *gi = &ai->groups[group];
+
+ group_offsets[group] = gi->base_offset;
+ group_sizes[group] = gi->nr_units * ai->unit_size;
+
+ for (i = 0; i < gi->nr_units; i++) {
+ cpu = gi->cpu_map[i];
+ if (cpu == NR_CPUS)
+ continue;
+
+ PCPU_SETUP_BUG_ON(cpu >= nr_cpu_ids);
+ PCPU_SETUP_BUG_ON(!cpu_possible(cpu));
+ PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX);
+
+ unit_map[cpu] = unit + i;
+ unit_off[cpu] = gi->base_offset + i * ai->unit_size;
+
+ /* determine low/high unit_cpu */
+ if (pcpu_low_unit_cpu == NR_CPUS ||
+ unit_off[cpu] < unit_off[pcpu_low_unit_cpu])
+ pcpu_low_unit_cpu = cpu;
+ if (pcpu_high_unit_cpu == NR_CPUS ||
+ unit_off[cpu] > unit_off[pcpu_high_unit_cpu])
+ pcpu_high_unit_cpu = cpu;
+ }
+ }
+ pcpu_nr_units = unit;
+
+ for_each_possible_cpu(cpu)
+ PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX);
+
+ /* we're done parsing the input, undefine BUG macro and dump config */
+#undef PCPU_SETUP_BUG_ON
+ pcpu_dump_alloc_info(KERN_DEBUG, ai);
+
+ pcpu_nr_groups = ai->nr_groups;
+ pcpu_group_offsets = group_offsets;
+ pcpu_group_sizes = group_sizes;
+ pcpu_unit_map = unit_map;
+ pcpu_unit_offsets = unit_off;
+
+ /* determine basic parameters */
+ pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
+ pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
+ pcpu_atom_size = ai->atom_size;
+ pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
+ BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);
+
+ /*
+ * Allocate chunk slots. The additional last slot is for
+ * empty chunks.
+ */
+ pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2;
+ pcpu_slot = memblock_virt_alloc(
+ pcpu_nr_slots * sizeof(pcpu_slot[0]), 0);
+ for (i = 0; i < pcpu_nr_slots; i++)
+ INIT_LIST_HEAD(&pcpu_slot[i]);
+
+ /*
+ * Initialize static chunk. If reserved_size is zero, the
+ * static chunk covers static area + dynamic allocation area
+ * in the first chunk. If reserved_size is not zero, it
+ * covers static area + reserved area (mostly used for module
+ * static percpu allocation).
+ */
+ schunk = memblock_virt_alloc(pcpu_chunk_struct_size, 0);
+ INIT_LIST_HEAD(&schunk->list);
+ INIT_WORK(&schunk->map_extend_work, pcpu_map_extend_workfn);
+ schunk->base_addr = base_addr;
+ schunk->map = smap;
+ schunk->map_alloc = ARRAY_SIZE(smap);
+ schunk->immutable = true;
+ bitmap_fill(schunk->populated, pcpu_unit_pages);
+ schunk->nr_populated = pcpu_unit_pages;
+
+ if (ai->reserved_size) {
+ schunk->free_size = ai->reserved_size;
+ pcpu_reserved_chunk = schunk;
+ pcpu_reserved_chunk_limit = ai->static_size + ai->reserved_size;
+ } else {
+ schunk->free_size = dyn_size;
+ dyn_size = 0; /* dynamic area covered */
+ }
+ schunk->contig_hint = schunk->free_size;
+
+ schunk->map[0] = 1;
+ schunk->map[1] = ai->static_size;
+ schunk->map_used = 1;
+ if (schunk->free_size)
+ schunk->map[++schunk->map_used] = 1 | (ai->static_size + schunk->free_size);
+ else
+ schunk->map[1] |= 1;
+
+ /* init dynamic chunk if necessary */
+ if (dyn_size) {
+ dchunk = memblock_virt_alloc(pcpu_chunk_struct_size, 0);
+ INIT_LIST_HEAD(&dchunk->list);
+ INIT_WORK(&dchunk->map_extend_work, pcpu_map_extend_workfn);
+ dchunk->base_addr = base_addr;
+ dchunk->map = dmap;
+ dchunk->map_alloc = ARRAY_SIZE(dmap);
+ dchunk->immutable = true;
+ bitmap_fill(dchunk->populated, pcpu_unit_pages);
+ dchunk->nr_populated = pcpu_unit_pages;
+
+ dchunk->contig_hint = dchunk->free_size = dyn_size;
+ dchunk->map[0] = 1;
+ dchunk->map[1] = pcpu_reserved_chunk_limit;
+ dchunk->map[2] = (pcpu_reserved_chunk_limit + dchunk->free_size) | 1;
+ dchunk->map_used = 2;
+ }
+
+ /* link the first chunk in */
+ pcpu_first_chunk = dchunk ?: schunk;
+ pcpu_nr_empty_pop_pages +=
+ pcpu_count_occupied_pages(pcpu_first_chunk, 1);
+ pcpu_chunk_relocate(pcpu_first_chunk, -1);
+
+ /* we're done */
+ pcpu_base_addr = base_addr;
+ return 0;
+}
+
+#ifdef CONFIG_SMP
+
+const char * const pcpu_fc_names[PCPU_FC_NR] __initconst = {
+ [PCPU_FC_AUTO] = "auto",
+ [PCPU_FC_EMBED] = "embed",
+ [PCPU_FC_PAGE] = "page",
+};
+
+enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO;
+
+static int __init percpu_alloc_setup(char *str)
+{
+ if (!str)
+ return -EINVAL;
+
+ if (0)
+ /* nada */;
+#ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
+ else if (!strcmp(str, "embed"))
+ pcpu_chosen_fc = PCPU_FC_EMBED;
+#endif
+#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
+ else if (!strcmp(str, "page"))
+ pcpu_chosen_fc = PCPU_FC_PAGE;
+#endif
+ else
+ pr_warning("PERCPU: unknown allocator %s specified\n", str);
+
+ return 0;
+}
+early_param("percpu_alloc", percpu_alloc_setup);
+
+/*
+ * pcpu_embed_first_chunk() is used by the generic percpu setup.
+ * Build it if needed by the arch config or the generic setup is going
+ * to be used.
+ */
+#if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \
+ !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
+#define BUILD_EMBED_FIRST_CHUNK
+#endif
+
+/* build pcpu_page_first_chunk() iff needed by the arch config */
+#if defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK)
+#define BUILD_PAGE_FIRST_CHUNK
+#endif
+
+/* pcpu_build_alloc_info() is used by both embed and page first chunk */
+#if defined(BUILD_EMBED_FIRST_CHUNK) || defined(BUILD_PAGE_FIRST_CHUNK)
+/**
+ * pcpu_build_alloc_info - build alloc_info considering distances between CPUs
+ * @reserved_size: the size of reserved percpu area in bytes
+ * @dyn_size: minimum free size for dynamic allocation in bytes
+ * @atom_size: allocation atom size
+ * @cpu_distance_fn: callback to determine distance between cpus, optional
+ *
+ * This function determines grouping of units, their mappings to cpus
+ * and other parameters considering needed percpu size, allocation
+ * atom size and distances between CPUs.
+ *
+ * Groups are always multiples of atom size and CPUs which are of
+ * LOCAL_DISTANCE both ways are grouped together and share space for
+ * units in the same group. The returned configuration is guaranteed
+ * to have CPUs on different nodes on different groups and >=75% usage
+ * of allocated virtual address space.
+ *
+ * RETURNS:
+ * On success, pointer to the new allocation_info is returned. On
+ * failure, ERR_PTR value is returned.
+ */
+static struct pcpu_alloc_info * __init pcpu_build_alloc_info(
+ size_t reserved_size, size_t dyn_size,
+ size_t atom_size,
+ pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
+{
+ static int group_map[NR_CPUS] __initdata;
+ static int group_cnt[NR_CPUS] __initdata;
+ const size_t static_size = __per_cpu_end - __per_cpu_start;
+ int nr_groups = 1, nr_units = 0;
+ size_t size_sum, min_unit_size, alloc_size;
+ int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */
+ int last_allocs, group, unit;
+ unsigned int cpu, tcpu;
+ struct pcpu_alloc_info *ai;
+ unsigned int *cpu_map;
+
+ /* this function may be called multiple times */
+ memset(group_map, 0, sizeof(group_map));
+ memset(group_cnt, 0, sizeof(group_cnt));
+
+ /* calculate size_sum and ensure dyn_size is enough for early alloc */
+ size_sum = PFN_ALIGN(static_size + reserved_size +
+ max_t(size_t, dyn_size, PERCPU_DYNAMIC_EARLY_SIZE));
+ dyn_size = size_sum - static_size - reserved_size;
+
+ /*
+ * Determine min_unit_size, alloc_size and max_upa such that
+ * alloc_size is multiple of atom_size and is the smallest
+ * which can accommodate 4k aligned segments which are equal to
+ * or larger than min_unit_size.
+ */
+ min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
+
+ alloc_size = roundup(min_unit_size, atom_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_distance_fn(cpu, tcpu) > LOCAL_DISTANCE ||
+ cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) {
+ group++;
+ nr_groups = max(nr_groups, group + 1);
+ goto next_group;
+ }
+ }
+ group_map[cpu] = group;
+ 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 < nr_groups; 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 1/3. 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;
+ }
+ upa = best_upa;
+
+ /* allocate and fill alloc_info */
+ for (group = 0; group < nr_groups; group++)
+ nr_units += roundup(group_cnt[group], upa);
+
+ ai = pcpu_alloc_alloc_info(nr_groups, nr_units);
+ if (!ai)
+ return ERR_PTR(-ENOMEM);
+ cpu_map = ai->groups[0].cpu_map;
+
+ for (group = 0; group < nr_groups; group++) {
+ ai->groups[group].cpu_map = cpu_map;
+ cpu_map += roundup(group_cnt[group], upa);
+ }
+
+ ai->static_size = static_size;
+ ai->reserved_size = reserved_size;
+ ai->dyn_size = dyn_size;
+ ai->unit_size = alloc_size / upa;
+ ai->atom_size = atom_size;
+ ai->alloc_size = alloc_size;
+
+ for (group = 0, unit = 0; group_cnt[group]; group++) {
+ struct pcpu_group_info *gi = &ai->groups[group];
+
+ /*
+ * Initialize base_offset as if all groups are located
+ * back-to-back. The caller should update this to
+ * reflect actual allocation.
+ */
+ gi->base_offset = unit * ai->unit_size;
+
+ for_each_possible_cpu(cpu)
+ if (group_map[cpu] == group)
+ gi->cpu_map[gi->nr_units++] = cpu;
+ gi->nr_units = roundup(gi->nr_units, upa);
+ unit += gi->nr_units;
+ }
+ BUG_ON(unit != nr_units);
+
+ return ai;
+}
+#endif /* BUILD_EMBED_FIRST_CHUNK || BUILD_PAGE_FIRST_CHUNK */
+
+#if defined(BUILD_EMBED_FIRST_CHUNK)
+/**
+ * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
+ * @reserved_size: the size of reserved percpu area in bytes
+ * @dyn_size: minimum free size for dynamic allocation in bytes
+ * @atom_size: allocation atom size
+ * @cpu_distance_fn: callback to determine distance between cpus, optional
+ * @alloc_fn: function to allocate percpu page
+ * @free_fn: function to free percpu page
+ *
+ * This is a helper to ease setting up embedded first percpu chunk and
+ * can be called where pcpu_setup_first_chunk() is expected.
+ *
+ * If this function is used to setup the first chunk, it is allocated
+ * by calling @alloc_fn and used as-is without being mapped into
+ * vmalloc area. Allocations are always whole multiples of @atom_size
+ * aligned to @atom_size.
+ *
+ * This enables the first chunk to piggy back on the linear physical
+ * mapping which often uses larger page size. Please note that this
+ * can result in very sparse cpu->unit mapping on NUMA machines thus
+ * requiring large vmalloc address space. Don't use this allocator if
+ * vmalloc space is not orders of magnitude larger than distances
+ * between node memory addresses (ie. 32bit NUMA machines).
+ *
+ * @dyn_size specifies the minimum dynamic area size.
+ *
+ * If the needed size is smaller than the minimum or specified unit
+ * size, the leftover is returned using @free_fn.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
+ size_t atom_size,
+ pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
+ pcpu_fc_alloc_fn_t alloc_fn,
+ pcpu_fc_free_fn_t free_fn)
+{
+ void *base = (void *)ULONG_MAX;
+ void **areas = NULL;
+ struct pcpu_alloc_info *ai;
+ size_t size_sum, areas_size, max_distance;
+ int group, i, rc;
+
+ ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size,
+ cpu_distance_fn);
+ if (IS_ERR(ai))
+ return PTR_ERR(ai);
+
+ size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
+ areas_size = PFN_ALIGN(ai->nr_groups * sizeof(void *));
+
+ areas = memblock_virt_alloc_nopanic(areas_size, 0);
+ if (!areas) {
+ rc = -ENOMEM;
+ goto out_free;
+ }
+
+ /* allocate, copy and determine base address */
+ for (group = 0; group < ai->nr_groups; group++) {
+ struct pcpu_group_info *gi = &ai->groups[group];
+ unsigned int cpu = NR_CPUS;
+ void *ptr;
+
+ for (i = 0; i < gi->nr_units && cpu == NR_CPUS; i++)
+ cpu = gi->cpu_map[i];
+ BUG_ON(cpu == NR_CPUS);
+
+ /* allocate space for the whole group */
+ ptr = alloc_fn(cpu, gi->nr_units * ai->unit_size, atom_size);
+ if (!ptr) {
+ rc = -ENOMEM;
+ goto out_free_areas;
+ }
+ /* kmemleak tracks the percpu allocations separately */
+ kmemleak_free(ptr);
+ areas[group] = ptr;
+
+ base = min(ptr, base);
+ }
+
+ /*
+ * Copy data and free unused parts. This should happen after all
+ * allocations are complete; otherwise, we may end up with
+ * overlapping groups.
+ */
+ for (group = 0; group < ai->nr_groups; group++) {
+ struct pcpu_group_info *gi = &ai->groups[group];
+ void *ptr = areas[group];
+
+ for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) {
+ if (gi->cpu_map[i] == NR_CPUS) {
+ /* unused unit, free whole */
+ free_fn(ptr, ai->unit_size);
+ continue;
+ }
+ /* copy and return the unused part */
+ memcpy(ptr, __per_cpu_load, ai->static_size);
+ free_fn(ptr + size_sum, ai->unit_size - size_sum);
+ }
+ }
+
+ /* base address is now known, determine group base offsets */
+ max_distance = 0;
+ for (group = 0; group < ai->nr_groups; group++) {
+ ai->groups[group].base_offset = areas[group] - base;
+ max_distance = max_t(size_t, max_distance,
+ ai->groups[group].base_offset);
+ }
+ max_distance += ai->unit_size;
+
+ /* warn if maximum distance is further than 75% of vmalloc space */
+ if (max_distance > VMALLOC_TOTAL * 3 / 4) {
+ pr_warning("PERCPU: max_distance=0x%zx too large for vmalloc "
+ "space 0x%lx\n", max_distance,
+ VMALLOC_TOTAL);
+#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
+ /* and fail if we have fallback */
+ rc = -EINVAL;
+ goto out_free;
+#endif
+ }
+
+ pr_info("PERCPU: Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n",
+ PFN_DOWN(size_sum), base, ai->static_size, ai->reserved_size,
+ ai->dyn_size, ai->unit_size);
+
+ rc = pcpu_setup_first_chunk(ai, base);
+ goto out_free;
+
+out_free_areas:
+ for (group = 0; group < ai->nr_groups; group++)
+ if (areas[group])
+ free_fn(areas[group],
+ ai->groups[group].nr_units * ai->unit_size);
+out_free:
+ pcpu_free_alloc_info(ai);
+ if (areas)
+ memblock_free_early(__pa(areas), areas_size);
+ return rc;
+}
+#endif /* BUILD_EMBED_FIRST_CHUNK */
+
+#ifdef BUILD_PAGE_FIRST_CHUNK
+/**
+ * pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages
+ * @reserved_size: the size of reserved percpu area in bytes
+ * @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE
+ * @free_fn: function to free percpu page, always called with PAGE_SIZE
+ * @populate_pte_fn: function to populate pte
+ *
+ * This is a helper to ease setting up page-remapped first percpu
+ * chunk and can be called where pcpu_setup_first_chunk() is expected.
+ *
+ * This is the basic allocator. Static percpu area is allocated
+ * page-by-page into vmalloc area.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+int __init pcpu_page_first_chunk(size_t reserved_size,
+ pcpu_fc_alloc_fn_t alloc_fn,
+ pcpu_fc_free_fn_t free_fn,
+ pcpu_fc_populate_pte_fn_t populate_pte_fn)
+{
+ static struct vm_struct vm;
+ struct pcpu_alloc_info *ai;
+ char psize_str[16];
+ int unit_pages;
+ size_t pages_size;
+ struct page **pages;
+ int unit, i, j, rc;
+
+ snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10);
+
+ ai = pcpu_build_alloc_info(reserved_size, 0, PAGE_SIZE, NULL);
+ if (IS_ERR(ai))
+ return PTR_ERR(ai);
+ BUG_ON(ai->nr_groups != 1);
+ BUG_ON(ai->groups[0].nr_units != num_possible_cpus());
+
+ unit_pages = ai->unit_size >> PAGE_SHIFT;
+
+ /* unaligned allocations can't be freed, round up to page size */
+ pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() *
+ sizeof(pages[0]));
+ pages = memblock_virt_alloc(pages_size, 0);
+
+ /* allocate pages */
+ j = 0;
+ for (unit = 0; unit < num_possible_cpus(); unit++)
+ for (i = 0; i < unit_pages; i++) {
+ unsigned int cpu = ai->groups[0].cpu_map[unit];
+ void *ptr;
+
+ ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE);
+ if (!ptr) {
+ pr_warning("PERCPU: failed to allocate %s page "
+ "for cpu%u\n", psize_str, cpu);
+ goto enomem;
+ }
+ /* kmemleak tracks the percpu allocations separately */
+ kmemleak_free(ptr);
+ pages[j++] = virt_to_page(ptr);
+ }
+
+ /* allocate vm area, map the pages and copy static data */
+ vm.flags = VM_ALLOC;
+ vm.size = num_possible_cpus() * ai->unit_size;
+ vm_area_register_early(&vm, PAGE_SIZE);
+
+ for (unit = 0; unit < num_possible_cpus(); unit++) {
+ unsigned long unit_addr =
+ (unsigned long)vm.addr + unit * ai->unit_size;
+
+ for (i = 0; i < unit_pages; i++)
+ populate_pte_fn(unit_addr + (i << PAGE_SHIFT));
+
+ /* pte already populated, the following shouldn't fail */
+ rc = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages],
+ unit_pages);
+ if (rc < 0)
+ panic("failed to map percpu area, err=%d\n", rc);
+
+ /*
+ * FIXME: Archs with virtual cache should flush local
+ * cache for the linear mapping here - something
+ * equivalent to flush_cache_vmap() on the local cpu.
+ * flush_cache_vmap() can't be used as most supporting
+ * data structures are not set up yet.
+ */
+
+ /* copy static data */
+ memcpy((void *)unit_addr, __per_cpu_load, ai->static_size);
+ }
+
+ /* we're ready, commit */
+ pr_info("PERCPU: %d %s pages/cpu @%p s%zu r%zu d%zu\n",
+ unit_pages, psize_str, vm.addr, ai->static_size,
+ ai->reserved_size, ai->dyn_size);
+
+ rc = pcpu_setup_first_chunk(ai, vm.addr);
+ goto out_free_ar;
+
+enomem:
+ while (--j >= 0)
+ free_fn(page_address(pages[j]), PAGE_SIZE);
+ rc = -ENOMEM;
+out_free_ar:
+ memblock_free_early(__pa(pages), pages_size);
+ pcpu_free_alloc_info(ai);
+ return rc;
+}
+#endif /* BUILD_PAGE_FIRST_CHUNK */
+
+#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
+/*
+ * Generic SMP percpu area setup.
+ *
+ * The embedding helper is used because its behavior closely resembles
+ * the original non-dynamic generic percpu area setup. This is
+ * important because many archs have addressing restrictions and might
+ * fail if the percpu area is located far away from the previous
+ * location. As an added bonus, in non-NUMA cases, embedding is
+ * generally a good idea TLB-wise because percpu area can piggy back
+ * on the physical linear memory mapping which uses large page
+ * mappings on applicable archs.
+ */
+unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
+EXPORT_SYMBOL(__per_cpu_offset);
+
+static void * __init pcpu_dfl_fc_alloc(unsigned int cpu, size_t size,
+ size_t align)
+{
+ return memblock_virt_alloc_from_nopanic(
+ size, align, __pa(MAX_DMA_ADDRESS));
+}
+
+static void __init pcpu_dfl_fc_free(void *ptr, size_t size)
+{
+ memblock_free_early(__pa(ptr), size);
+}
+
+void __init setup_per_cpu_areas(void)
+{
+ unsigned long delta;
+ unsigned int cpu;
+ int rc;
+
+ /*
+ * Always reserve area for module percpu variables. That's
+ * what the legacy allocator did.
+ */
+ rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
+ PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, NULL,
+ pcpu_dfl_fc_alloc, pcpu_dfl_fc_free);
+ if (rc < 0)
+ panic("Failed to initialize percpu areas.");
+
+ delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
+ for_each_possible_cpu(cpu)
+ __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
+}
+#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
+
+#else /* CONFIG_SMP */
+
+/*
+ * UP percpu area setup.
+ *
+ * UP always uses km-based percpu allocator with identity mapping.
+ * Static percpu variables are indistinguishable from the usual static
+ * variables and don't require any special preparation.
+ */
+void __init setup_per_cpu_areas(void)
+{
+ const size_t unit_size =
+ roundup_pow_of_two(max_t(size_t, PCPU_MIN_UNIT_SIZE,
+ PERCPU_DYNAMIC_RESERVE));
+ struct pcpu_alloc_info *ai;
+ void *fc;
+
+ ai = pcpu_alloc_alloc_info(1, 1);
+ fc = memblock_virt_alloc_from_nopanic(unit_size,
+ PAGE_SIZE,
+ __pa(MAX_DMA_ADDRESS));
+ if (!ai || !fc)
+ panic("Failed to allocate memory for percpu areas.");
+ /* kmemleak tracks the percpu allocations separately */
+ kmemleak_free(fc);
+
+ ai->dyn_size = unit_size;
+ ai->unit_size = unit_size;
+ ai->atom_size = unit_size;
+ ai->alloc_size = unit_size;
+ ai->groups[0].nr_units = 1;
+ ai->groups[0].cpu_map[0] = 0;
+
+ if (pcpu_setup_first_chunk(ai, fc) < 0)
+ panic("Failed to initialize percpu areas.");
+}
+
+#endif /* CONFIG_SMP */
+
+/*
+ * First and reserved chunks are initialized with temporary allocation
+ * map in initdata so that they can be used before slab is online.
+ * This function is called after slab is brought up and replaces those
+ * with properly allocated maps.
+ */
+void __init percpu_init_late(void)
+{
+ struct pcpu_chunk *target_chunks[] =
+ { pcpu_first_chunk, pcpu_reserved_chunk, NULL };
+ struct pcpu_chunk *chunk;
+ unsigned long flags;
+ int i;
+
+ for (i = 0; (chunk = target_chunks[i]); i++) {
+ int *map;
+ const size_t size = PERCPU_DYNAMIC_EARLY_SLOTS * sizeof(map[0]);
+
+ BUILD_BUG_ON(size > PAGE_SIZE);
+
+ map = pcpu_mem_zalloc(size);
+ BUG_ON(!map);
+
+ spin_lock_irqsave(&pcpu_lock, flags);
+ memcpy(map, chunk->map, size);
+ chunk->map = map;
+ spin_unlock_irqrestore(&pcpu_lock, flags);
+ }
+}
+
+/*
+ * Percpu allocator is initialized early during boot when neither slab or
+ * workqueue is available. Plug async management until everything is up
+ * and running.
+ */
+static int __init percpu_enable_async(void)
+{
+ pcpu_async_enabled = true;
+ return 0;
+}
+subsys_initcall(percpu_enable_async);
Code Review / kvmfornfv.git / blobdiff