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/*
* Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/atomic.h>
#include "gk20a_allocator.h"
#include "lockless_allocator_priv.h"
static u64 gk20a_lockless_alloc_length(struct gk20a_allocator *a)
{
struct gk20a_lockless_allocator *pa = a->priv;
return pa->length;
}
static u64 gk20a_lockless_alloc_base(struct gk20a_allocator *a)
{
struct gk20a_lockless_allocator *pa = a->priv;
return pa->base;
}
static int gk20a_lockless_alloc_inited(struct gk20a_allocator *a)
{
struct gk20a_lockless_allocator *pa = a->priv;
int inited = pa->inited;
rmb();
return inited;
}
static u64 gk20a_lockless_alloc_end(struct gk20a_allocator *a)
{
struct gk20a_lockless_allocator *pa = a->priv;
return pa->base + pa->length;
}
static u64 gk20a_lockless_alloc(struct gk20a_allocator *a, u64 len)
{
struct gk20a_lockless_allocator *pa = a->priv;
int head, new_head, ret;
u64 addr = 0;
if (len != pa->blk_size)
return 0;
head = ACCESS_ONCE(pa->head);
while (head >= 0) {
new_head = ACCESS_ONCE(pa->next[head]);
ret = cmpxchg(&pa->head, head, new_head);
if (ret == head) {
addr = pa->base + head * pa->blk_size;
atomic_inc(&pa->nr_allocs);
alloc_dbg(a, "Alloc node # %d @ addr 0x%llx\n", head,
addr);
break;
}
head = ACCESS_ONCE(pa->head);
}
return addr;
}
static void gk20a_lockless_free(struct gk20a_allocator *a, u64 addr)
{
struct gk20a_lockless_allocator *pa = a->priv;
int head, ret;
u64 cur_idx, rem;
cur_idx = addr - pa->base;
rem = do_div(cur_idx, pa->blk_size);
while (1) {
head = ACCESS_ONCE(pa->head);
ACCESS_ONCE(pa->next[cur_idx]) = head;
ret = cmpxchg(&pa->head, head, cur_idx);
if (ret == head) {
atomic_dec(&pa->nr_allocs);
alloc_dbg(a, "Free node # %llu\n", cur_idx);
break;
}
}
}
static void gk20a_lockless_alloc_destroy(struct gk20a_allocator *a)
{
struct gk20a_lockless_allocator *pa = a->priv;
gk20a_fini_alloc_debug(a);
vfree(pa->next);
kfree(pa);
}
static void gk20a_lockless_print_stats(struct gk20a_allocator *a,
struct seq_file *s, int lock)
{
struct gk20a_lockless_allocator *pa = a->priv;
__alloc_pstat(s, a, "Lockless allocator params:\n");
__alloc_pstat(s, a, " start = 0x%llx\n", pa->base);
__alloc_pstat(s, a, " end = 0x%llx\n", pa->base + pa->length);
/* Actual stats. */
__alloc_pstat(s, a, "Stats:\n");
__alloc_pstat(s, a, " Number allocs = %d\n",
atomic_read(&pa->nr_allocs));
__alloc_pstat(s, a, " Number free = %d\n",
pa->nr_nodes - atomic_read(&pa->nr_allocs));
}
static const struct gk20a_allocator_ops pool_ops = {
.alloc = gk20a_lockless_alloc,
.free = gk20a_lockless_free,
.base = gk20a_lockless_alloc_base,
.length = gk20a_lockless_alloc_length,
.end = gk20a_lockless_alloc_end,
.inited = gk20a_lockless_alloc_inited,
.fini = gk20a_lockless_alloc_destroy,
.print_stats = gk20a_lockless_print_stats,
};
int gk20a_lockless_allocator_init(struct gk20a *g, struct gk20a_allocator *__a,
const char *name, u64 base, u64 length,
u64 blk_size, u64 flags)
{
int i;
int err;
int nr_nodes;
u64 count, rem;
struct gk20a_lockless_allocator *a;
if (!blk_size)
return -EINVAL;
/*
* Ensure we have space for atleast one node & there's no overflow.
* In order to control memory footprint, we require count < INT_MAX
*/
count = length;
rem = do_div(count, blk_size);
if (!base || !count || count > INT_MAX)
return -EINVAL;
a = kzalloc(sizeof(struct gk20a_lockless_allocator), GFP_KERNEL);
if (!a)
return -ENOMEM;
err = __gk20a_alloc_common_init(__a, name, a, false, &pool_ops);
if (err)
goto fail;
a->next = vzalloc(sizeof(*a->next) * count);
if (!a->next) {
err = -ENOMEM;
goto fail;
}
/* chain the elements together to form the initial free list */
nr_nodes = (int)count;
for (i = 0; i < nr_nodes; i++)
a->next[i] = i + 1;
a->next[nr_nodes - 1] = -1;
a->base = base;
a->length = length;
a->blk_size = blk_size;
a->nr_nodes = nr_nodes;
a->flags = flags;
atomic_set(&a->nr_allocs, 0);
wmb();
a->inited = true;
gk20a_init_alloc_debug(g, __a);
alloc_dbg(__a, "New allocator: type lockless\n");
alloc_dbg(__a, " base 0x%llx\n", a->base);
alloc_dbg(__a, " nodes %d\n", a->nr_nodes);
alloc_dbg(__a, " blk_size 0x%llx\n", a->blk_size);
alloc_dbg(__a, " flags 0x%llx\n", a->flags);
return 0;
fail:
kfree(a);
return err;
}
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