#include "error.h"
#include "sched.h"
+struct btr_pool {
+ char *name;
+ char *area_start;
+ char *area_end;
+ char *rhead;
+ char *whead;
+};
+
+enum btr_buffer_flags {
+ /* changes the way the buffer is deallocated */
+ BTR_BF_BTR_POOL = 1,
+};
struct btr_buffer {
char *buf;
size_t size;
/** The number of references to this buffer. */
int refcount;
+ struct btr_pool *pool;
};
struct btr_buffer_reference {
size_t consumed;
/* Each buffer reference belongs to the buffer queue list of some buffer tree node. */
struct list_head node;
+ size_t wrap_count;
};
struct btr_node {
void *context;
};
+struct btr_pool *btr_pool_new(const char *name, size_t area_size)
+{
+ struct btr_pool *btrp;
+
+ PARA_INFO_LOG("%s, %zu bytes\n", name, area_size);
+ btrp = para_malloc(sizeof(*btrp));
+ btrp->area_start = para_malloc(area_size);
+ btrp->area_end = btrp->area_start + area_size;
+ btrp->rhead = btrp->area_start;
+ btrp->whead = btrp->area_start;
+ btrp->name = para_strdup(name);
+ return btrp;
+}
+
+/* whead = NULL means area full */
+
+void btr_pool_free(struct btr_pool *btrp)
+{
+ if (!btrp)
+ return;
+ free(btrp->area_start);
+ free(btrp->name);
+ free(btrp);
+}
+
+size_t btr_pool_size(struct btr_pool *btrp)
+{
+ return btrp->area_end - btrp->area_start;
+}
+
+size_t btr_pool_filled(struct btr_pool *btrp)
+{
+ if (!btrp->whead)
+ return btr_pool_size(btrp);
+ if (btrp->rhead <= btrp->whead)
+ return btrp->whead - btrp->rhead;
+ return btr_pool_size(btrp) - (btrp->rhead - btrp->whead);
+}
+
+size_t btr_pool_unused(struct btr_pool *btrp)
+{
+ return btr_pool_size(btrp) - btr_pool_filled(btrp);
+}
+
+size_t btr_pool_available(struct btr_pool *btrp)
+{
+ if (!btrp->whead)
+ return 0;
+ if (btrp->rhead <= btrp->whead)
+ return btrp->area_end - btrp->whead;
+ return btrp->rhead - btrp->whead;
+}
+
+size_t btr_pool_get_buffer(struct btr_pool *btrp, char **result)
+{
+ if (result)
+ *result = btrp->whead;
+ return btr_pool_available(btrp);
+}
+
+void btr_pool_allocate(struct btr_pool *btrp, size_t size)
+{
+ char *end;
+
+ if (size == 0)
+ return;
+ //PARA_CRIT_LOG("filled: %zu, alloc %zu\n", btr_pool_filled(btrp), size);
+ assert(size <= btr_pool_available(btrp));
+ end = btrp->whead + size;
+ assert(end <= btrp->area_end);
+
+ if (end == btrp->area_end) {
+ PARA_DEBUG_LOG("end of pool area reached: %p\n", end);
+ end = btrp->area_start;
+ }
+ if (end == btrp->rhead) {
+ PARA_DEBUG_LOG("btrp buffer full\n");
+ end = NULL; /* buffer full */
+ }
+ btrp->whead = end;
+ //PARA_CRIT_LOG("filled: %zu\n", btr_pool_filled(btrp));
+}
+
+static void btr_pool_deallocate(struct btr_pool *btrp, size_t size)
+{
+ char *end = btrp->rhead + size;
+
+ //PARA_CRIT_LOG("filled: %zu, dealloc %zu\n", btr_pool_filled(btrp), size);
+ if (size == 0)
+ return;
+ assert(end <= btrp->area_end);
+ assert(size <= btr_pool_filled(btrp));
+ if (end == btrp->area_end)
+ end = btrp->area_start;
+ if (!btrp->whead)
+ btrp->whead = btrp->rhead;
+ btrp->rhead = end;
+ if (btrp->rhead == btrp->whead)
+ btrp->rhead = btrp->whead = btrp->area_start;
+ //PARA_CRIT_LOG("filled: %zu\n", btr_pool_filled(btrp));
+}
+
#define FOR_EACH_CHILD(_tn, _btrn) list_for_each_entry((_tn), \
&((_btrn)->children), node)
#define FOR_EACH_CHILD_SAFE(_tn, _tmp, _btrn) \
*/
static struct btr_buffer *new_btrb(char *buf, size_t size)
{
- struct btr_buffer *btrb = para_malloc(sizeof(*btrb));
+ struct btr_buffer *btrb = para_calloc(sizeof(*btrb));
btrb->buf = buf;
btrb->size = size;
- btrb->refcount = 0;
return btrb;
}
+static void dealloc_buffer(struct btr_buffer *btrb)
+{
+ if (btrb->pool)
+ btr_pool_deallocate(btrb->pool, btrb->size);
+ else
+ free(btrb->buf);
+}
+
+static struct btr_buffer_reference *get_first_input_br(struct btr_node *btrn)
+{
+ if (list_empty(&btrn->input_queue))
+ return NULL;
+ return list_first_entry(&btrn->input_queue,
+ struct btr_buffer_reference, node);
+}
+
/*
* Deallocate the reference, release the resources if refcount drops to zero.
*/
free(br);
btrb->refcount--;
if (btrb->refcount == 0) {
- free(btrb->buf);
+ dealloc_buffer(btrb);
free(btrb);
}
}
if (btrn->start.tv_sec == 0)
btrn->start = *now;
FOR_EACH_CHILD(ch, btrn) {
- struct btr_buffer_reference *br = para_malloc(sizeof(*br));
+ struct btr_buffer_reference *br = para_calloc(sizeof(*br));
br->btrb = btrb;
br->consumed = consumed;
list_add_tail(&br->node, &ch->input_queue);
add_btrb_to_children(btrb, btrn, 0);
}
+void btr_add_output_pool(struct btr_pool *btrp, size_t size,
+ struct btr_node *btrn)
+{
+ struct btr_buffer *btrb;
+ char *buf;
+ size_t avail;
+
+ assert(size != 0);
+ if (list_empty(&btrn->children))
+ return;
+ avail = btr_pool_get_buffer(btrp, &buf);
+ assert(avail >= size);
+ btr_pool_allocate(btrp, size);
+ btrb = new_btrb(buf, size);
+ btrb->pool = btrp;
+ add_btrb_to_children(btrb, btrn, 0);
+}
+
+void btr_copy(const void *src, size_t n, struct btr_pool *btrp,
+ struct btr_node *btrn)
+{
+ char *buf;
+ size_t sz, copy;
+
+ if (n == 0)
+ return;
+ assert(n <= btr_pool_unused(btrp));
+ sz = btr_pool_get_buffer(btrp, &buf);
+ copy = PARA_MIN(sz, n);
+ memcpy(buf, src, copy);
+ btr_add_output_pool(btrp, copy, btrn);
+ if (copy == n)
+ return;
+ sz = btr_pool_get_buffer(btrp, &buf);
+ assert(sz >= n - copy);
+ memcpy(buf, src + copy, n - copy);
+ btr_add_output_pool(btrp, n - copy, btrn);
+}
+
static void btr_pushdown_br(struct btr_buffer_reference *br, struct btr_node *btrn)
{
add_btrb_to_children(br->btrb, btrn, br->consumed);
size_t btr_get_buffer_by_reference(struct btr_buffer_reference *br, char **buf)
{
- *buf = br->btrb->buf + br->consumed;
+ if (buf)
+ *buf = br->btrb->buf + br->consumed;
return br_available_bytes(br);
}
size_t btr_next_buffer(struct btr_node *btrn, char **bufp)
{
struct btr_buffer_reference *br;
+ char *buf, *result = NULL;
+ size_t sz, rv = 0;
- if (list_empty(&btrn->input_queue)) {
- *bufp = NULL;
- return 0;
+ FOR_EACH_BUFFER_REF(br, btrn) {
+ sz = btr_get_buffer_by_reference(br, &buf);
+ if (!result) {
+ result = buf;
+ rv = sz;
+ if (!br->btrb->pool)
+ break;
+ continue;
+ }
+ if (!br->btrb->pool)
+ break;
+ if (result + rv != buf) {
+ PARA_DEBUG_LOG("%s: pool merge impossible: %p != %p\n",
+ btrn->name, result + rv, buf);
+ break;
+ }
+// PARA_CRIT_LOG("%s: inplace merge (%zu, %zu)->%zu\n", btrn->name,
+// rv, sz, rv + sz);
+// PARA_CRIT_LOG("%s: inplace merge %p (%zu)\n", btrn->name,
+// result, sz);
+ rv += sz;
}
- br = list_first_entry(&btrn->input_queue, struct btr_buffer_reference, node);
- return btr_get_buffer_by_reference(br, bufp);
+ if (bufp)
+ *bufp = result;
+ return rv;
}
void btr_consume(struct btr_node *btrn, size_t numbytes)
{
- struct btr_buffer_reference *br;
+ struct btr_buffer_reference *br, *tmp;
+ size_t sz;
- assert(!list_empty(&btrn->input_queue));
- br = list_first_entry(&btrn->input_queue, struct btr_buffer_reference, node);
- assert(br->consumed + numbytes <= br->btrb->size);
- br->consumed += numbytes;
- if (br->consumed == br->btrb->size)
- btr_drop_buffer_reference(br);
+ if (numbytes == 0)
+ return;
+ br = get_first_input_br(btrn);
+ assert(br);
+
+ //PARA_CRIT_LOG("wrap count: %zu\n", br->wrap_count);
+ if (br->wrap_count == 0) {
+ /*
+ * No wrap buffer. Drop buffer references whose buffer
+ * has been fully used. */
+ FOR_EACH_BUFFER_REF_SAFE(br, tmp, btrn) {
+ if (br->consumed + numbytes <= br->btrb->size) {
+ br->consumed += numbytes;
+ if (br->consumed == br->btrb->size)
+ btr_drop_buffer_reference(br);
+ return;
+ }
+ numbytes -= br->btrb->size - br->consumed;
+ btr_drop_buffer_reference(br);
+ }
+ assert(true);
+ }
+ /*
+
+ We have a wrap buffer, consume from it. If in total,
+ i.e. including previous calls to brt_consume(), less than
+ wrap_count has been consumed, there's nothing more we can do.
+
+ Otherwise we drop the wrap buffer and consume from subsequent
+ buffers of the input queue the correct amount of bytes. This
+ is the total number of bytes that have been consumed from the
+ wrap buffer.
+*/
+ PARA_DEBUG_LOG("consuming %zu/%zu bytes from wrap buffer\n", numbytes,
+ br_available_bytes(br));
+
+ assert(numbytes <= br_available_bytes(br));
+ if (br->consumed + numbytes < br->wrap_count) {
+ br->consumed += numbytes;
+ return;
+ }
+ PARA_DEBUG_LOG("dropping wrap buffer (%zu bytes)\n", br->btrb->size);
+ /* get rid of the wrap buffer */
+ sz = br->consumed + numbytes;
+ btr_drop_buffer_reference(br);
+ return btr_consume(btrn, sz);
}
static void flush_input_queue(struct btr_node *btrn)
return btrn->context;
}
+static bool need_buffer_pool_merge(struct btr_node *btrn)
+{
+ struct btr_buffer_reference *br = get_first_input_br(btrn);
+
+ if (!br)
+ return false;
+ if (br->wrap_count != 0)
+ return true;
+ if (br->btrb->pool)
+ return true;
+ return false;
+}
+
+static void merge_input_pool(struct btr_node *btrn, size_t dest_size)
+{
+ struct btr_buffer_reference *br, *wbr;
+ int num_refs; /* including wrap buffer */
+ char *buf, *buf1, *buf2 = NULL;
+ size_t sz, sz1, sz2 = 0, wsz;
+
+ if (list_empty(&btrn->input_queue))
+ return;
+
+ num_refs = 0;
+ FOR_EACH_BUFFER_REF(br, btrn) {
+ num_refs++;
+ sz = btr_get_buffer_by_reference(br, &buf);
+ if (br->wrap_count != 0) {
+ assert(!wbr);
+ assert(num_refs == 1);
+ wbr = br;
+ if (sz >= dest_size)
+ return;
+ continue;
+ }
+ if (!buf1) {
+ buf1 = buf;
+ sz1 = sz;
+ goto next;
+ }
+ if (buf1 + sz1 == buf) {
+ sz1 += sz;
+ goto next;
+ }
+ if (!buf2) {
+ buf2 = buf;
+ sz2 = sz;
+ goto next;
+ }
+ assert(buf2 + sz2 == buf);
+ sz2 += sz;
+next:
+ if (sz1 + sz2 >= dest_size)
+ break;
+ }
+ if (!wbr) {
+ assert(buf1);
+ if (!buf2) /* nothing to do */
+ return;
+ /* make a new wrap buffer combining buf1 and buf 2. */
+ sz = sz1 + sz2;
+ buf = para_malloc(sz);
+ PARA_DEBUG_LOG("merging input buffers: (%p:%zu, %p:%zu) -> %p:%zu\n",
+ buf1, sz1, buf2, sz2, buf, sz);
+ memcpy(buf, buf1, sz1);
+ memcpy(buf + sz1, buf2, sz2);
+ br = para_calloc(sizeof(*br));
+ br->btrb = new_btrb(buf, sz);
+ br->btrb->refcount = 1;
+ br->consumed = 0;
+ /* This is a wrap buffer */
+ br->wrap_count = sz1;
+ para_list_add(&br->node, &btrn->input_queue);
+ return;
+ }
+ /*
+ * We already have a wrap buffer, but it is too small. It might be
+ * partially used.
+ */
+ wsz = br_available_bytes(wbr);
+ if (wbr->wrap_count == sz1 && wbr->btrb->size >= sz1 + sz2) /* nothing we can do about it */
+ return;
+ assert(buf1 && buf2);
+ sz = sz1 + sz2 - wbr->btrb->size; /* amount of new data */
+ wbr->btrb->size += sz;
+ PARA_DEBUG_LOG("increasing wrap buffer to %zu\n", wbr->btrb->size);
+ wbr->btrb->buf = para_realloc(wbr->btrb->buf, wbr->btrb->size);
+ /* copy the new data to the end of the reallocated buffer */
+ assert(sz2 >= sz);
+ memcpy(wbr->btrb->buf + wbr->btrb->size - sz, buf2 + sz2 - sz, sz);
+}
+
/**
* Merge the first two input buffers into one.
*
}
/* make a new btrb that combines the two buffers and a br to it. */
sz = szs[0] + szs[1];
- PARA_DEBUG_LOG("merging input buffers: (%zu, %zu) -> %zu\n",
- szs[0], szs[1], sz);
buf = para_malloc(sz);
- /* TODO: Avoid this memcopy by introducing btr buffer pool. */
+ PARA_DEBUG_LOG("memory merging input buffers: (%zu, %zu) -> %zu\n",
+ szs[0], szs[1], sz);
memcpy(buf, bufs[0], szs[0]);
memcpy(buf + szs[0], bufs[1], szs[1]);
- br = para_malloc(sizeof(*br));
+ br = para_calloc(sizeof(*br));
br->btrb = new_btrb(buf, sz);
br->btrb->refcount = 1;
- br->consumed = 0;
/* replace the first two refs by the new one */
btr_drop_buffer_reference(brs[0]);
void btr_merge(struct btr_node *btrn, size_t dest_size)
{
+ if (need_buffer_pool_merge(btrn))
+ return merge_input_pool(btrn, dest_size);
for (;;) {
char *buf;
size_t len = btr_next_buffer(btrn, &buf);
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