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/*
* BIRD Internet Routing Daemon -- Raw allocation
*
* (c) 2020 Maria Matejka <mq@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include "nest/bird.h"
#include "lib/resource.h"
#include "lib/lists.h"
#include "lib/event.h"
#include "sysdep/unix/io-loop.h"
#include <stdlib.h>
#include <unistd.h>
#include <stdatomic.h>
#include <errno.h>
#ifdef HAVE_MMAP
#include <sys/mman.h>
#endif
long page_size = 0;
#ifdef HAVE_MMAP
#if DEBUGGING
#define FP_NODE_OFFSET 42
#else
#define FP_NODE_OFFSET 1
#endif
static _Bool use_fake = 0;
#else
static _Bool use_fake = 1;
#endif
static void *
alloc_sys_page(void)
{
void *ptr = mmap(NULL, page_size, PROT_WRITE | PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (ptr == MAP_FAILED)
bug("mmap(%lu) failed: %m", page_size);
return ptr;
}
extern int shutting_down; /* Shutdown requested. */
void *
alloc_page(void)
{
#ifdef HAVE_MMAP
if (!use_fake)
{
struct free_pages *fp = &birdloop_current->pages;
if (!fp->cnt)
return alloc_sys_page();
node *n = HEAD(fp->list);
rem_node(n);
if ((--fp->cnt < fp->min) && !shutting_down)
ev_send(fp->cleanup->list, fp->cleanup);
void *ptr = n - FP_NODE_OFFSET;
memset(ptr, 0, page_size);
return ptr;
}
else
#endif
{
#ifdef HAVE_ALIGNED_ALLOC
void *ret = aligned_alloc(page_size, page_size);
if (!ret)
bug("aligned_alloc(%lu) failed", page_size);
return ret;
#else
bug("BIRD should have already died on fatal error.");
#endif
}
}
void
free_page(void *ptr)
{
#ifdef HAVE_MMAP
if (!use_fake)
{
struct free_pages *fp = &birdloop_current->pages;
struct node *n = ptr;
n += FP_NODE_OFFSET;
memset(n, 0, sizeof(node));
add_tail(&fp->list, n);
if ((++fp->cnt > fp->max) && !shutting_down)
ev_send(fp->cleanup->list, fp->cleanup);
}
else
#endif
free(ptr);
}
#ifdef HAVE_MMAP
#define GFP (&main_birdloop.pages)
void
flush_pages(struct birdloop *loop)
{
ASSERT_DIE(birdloop_inside(loop->parent->loop));
struct free_pages *fp = &loop->pages;
struct free_pages *pfp = &loop->parent->loop->pages;
add_tail_list(&pfp->list, &fp->list);
pfp->cnt += fp->cnt;
fp->cnt = 0;
fp->list = (list) {};
fp->min = 0;
fp->max = 0;
rfree(fp->cleanup);
fp->cleanup = NULL;
}
static void
cleanup_pages(void *data)
{
struct birdloop *loop = data;
birdloop_enter(loop);
ASSERT_DIE(birdloop_inside(loop->parent->loop));
struct free_pages *fp = &loop->pages;
struct free_pages *pfp = &loop->parent->loop->pages;
while ((fp->cnt < fp->min) && (pfp->cnt > pfp->min))
{
node *n = HEAD(pfp->list);
rem_node(n);
add_tail(&fp->list, n);
fp->cnt++;
pfp->cnt--;
}
while (fp->cnt < fp->min)
{
node *n = alloc_sys_page();
add_tail(&fp->list, n + FP_NODE_OFFSET);
fp->cnt++;
}
while (fp->cnt > fp->max)
{
node *n = HEAD(fp->list);
rem_node(n);
add_tail(&pfp->list, n);
fp->cnt--;
pfp->cnt++;
}
birdloop_leave(loop);
if (!shutting_down && (pfp->cnt > pfp->max))
ev_send(pfp->cleanup->list, pfp->cleanup);
}
static void
cleanup_global_pages(void *data UNUSED)
{
while (GFP->cnt < GFP->max)
{
node *n = alloc_sys_page();
add_tail(&GFP->list, n + FP_NODE_OFFSET);
GFP->cnt++;
}
for (uint limit = GFP->cnt; (limit > 0) && (GFP->cnt > GFP->max); limit--)
{
node *n = TAIL(GFP->list);
rem_node(n);
if (munmap(n - FP_NODE_OFFSET, page_size) == 0)
GFP->cnt--;
else if (errno == ENOMEM)
add_head(&GFP->list, n);
else
bug("munmap(%p) failed: %m", n - FP_NODE_OFFSET);
}
}
void
init_pages(struct birdloop *loop)
{
struct free_pages *fp = &loop->pages;
init_list(&fp->list);
fp->cleanup = ev_new_init(loop->parent->loop->pool, cleanup_pages, loop);
fp->cleanup->list = (loop->parent->loop == &main_birdloop) ? &global_work_list : birdloop_event_list(loop->parent->loop);
fp->min = 4;
fp->max = 16;
for (fp->cnt = 0; fp->cnt < fp->min; fp->cnt++)
{
node *n = alloc_sys_page();
add_tail(&fp->list, n + FP_NODE_OFFSET);
}
}
static event global_free_pages_cleanup_event = { .hook = cleanup_global_pages, .list = &global_work_list };
void resource_sys_init(void)
{
if (!(page_size = sysconf(_SC_PAGESIZE)))
die("System page size must be non-zero");
if (u64_popcount(page_size) == 1)
{
init_list(&GFP->list);
GFP->cleanup = &global_free_pages_cleanup_event;
GFP->min = 0;
GFP->max = 256;
return;
}
#ifdef HAVE_ALIGNED_ALLOC
log(L_WARN "Got strange memory page size (%lu), using the aligned allocator instead", page_size);
#else
die("Got strange memory page size (%lu) and aligned_alloc is not available", page_size);
#endif
/* Too big or strange page, use the aligned allocator instead */
page_size = 4096;
use_fake = 1;
}
#else
void
resource_sys_init(void)
{
page_size = 4096;
use_fake = 1;
}
#endif
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