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-rw-r--r--src/svm/svm_fifo.c568
1 files changed, 568 insertions, 0 deletions
diff --git a/src/svm/svm_fifo.c b/src/svm/svm_fifo.c
new file mode 100644
index 00000000000..11f901931be
--- /dev/null
+++ b/src/svm/svm_fifo.c
@@ -0,0 +1,568 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "svm_fifo.h"
+
+/** create an svm fifo, in the current heap. Fails vs blow up the process */
+svm_fifo_t *
+svm_fifo_create (u32 data_size_in_bytes)
+{
+ svm_fifo_t *f;
+ pthread_mutexattr_t attr;
+ pthread_condattr_t cattr;
+
+ f = clib_mem_alloc_aligned_or_null (sizeof (*f) + data_size_in_bytes,
+ CLIB_CACHE_LINE_BYTES);
+ if (f == 0)
+ return 0;
+
+ memset (f, 0, sizeof (*f) + data_size_in_bytes);
+ f->nitems = data_size_in_bytes;
+ f->ooos_list_head = OOO_SEGMENT_INVALID_INDEX;
+
+ memset (&attr, 0, sizeof (attr));
+ memset (&cattr, 0, sizeof (cattr));
+
+ if (pthread_mutexattr_init (&attr))
+ clib_unix_warning ("mutexattr_init");
+ if (pthread_mutexattr_setpshared (&attr, PTHREAD_PROCESS_SHARED))
+ clib_unix_warning ("pthread_mutexattr_setpshared");
+ if (pthread_mutex_init (&f->mutex, &attr))
+ clib_unix_warning ("mutex_init");
+ if (pthread_mutexattr_destroy (&attr))
+ clib_unix_warning ("mutexattr_destroy");
+ if (pthread_condattr_init (&cattr))
+ clib_unix_warning ("condattr_init");
+ if (pthread_condattr_setpshared (&cattr, PTHREAD_PROCESS_SHARED))
+ clib_unix_warning ("condattr_setpshared");
+ if (pthread_cond_init (&f->condvar, &cattr))
+ clib_unix_warning ("cond_init1");
+ if (pthread_condattr_destroy (&cattr))
+ clib_unix_warning ("cond_init2");
+
+ return (f);
+}
+
+always_inline ooo_segment_t *
+ooo_segment_new (svm_fifo_t * f, u32 start, u32 length)
+{
+ ooo_segment_t *s;
+
+ pool_get (f->ooo_segments, s);
+
+ s->fifo_position = start;
+ s->length = length;
+
+ s->prev = s->next = OOO_SEGMENT_INVALID_INDEX;
+
+ return s;
+}
+
+always_inline void
+ooo_segment_del (svm_fifo_t * f, u32 index)
+{
+ ooo_segment_t *cur, *prev = 0, *next = 0;
+ cur = pool_elt_at_index (f->ooo_segments, index);
+
+ if (cur->next != OOO_SEGMENT_INVALID_INDEX)
+ {
+ next = pool_elt_at_index (f->ooo_segments, cur->next);
+ next->prev = cur->prev;
+ }
+
+ if (cur->prev != OOO_SEGMENT_INVALID_INDEX)
+ {
+ prev = pool_elt_at_index (f->ooo_segments, cur->prev);
+ prev->next = cur->next;
+ }
+ else
+ {
+ f->ooos_list_head = cur->next;
+ }
+
+ pool_put (f->ooo_segments, cur);
+}
+
+/**
+ * Add segment to fifo's out-of-order segment list. Takes care of merging
+ * adjacent segments and removing overlapping ones.
+ */
+static void
+ooo_segment_add (svm_fifo_t * f, u32 offset, u32 length)
+{
+ ooo_segment_t *s, *new_s, *prev, *next, *it;
+ u32 new_index, position, end_offset, s_sof, s_eof, s_index;
+
+ position = (f->tail + offset) % f->nitems;
+ end_offset = offset + length;
+
+ if (f->ooos_list_head == OOO_SEGMENT_INVALID_INDEX)
+ {
+ s = ooo_segment_new (f, position, length);
+ f->ooos_list_head = s - f->ooo_segments;
+ f->ooos_newest = f->ooos_list_head;
+ return;
+ }
+
+ /* Find first segment that starts after new segment */
+ s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
+ while (s->next != OOO_SEGMENT_INVALID_INDEX
+ && ooo_segment_offset (f, s) <= offset)
+ s = pool_elt_at_index (f->ooo_segments, s->next);
+
+ s_index = s - f->ooo_segments;
+ s_sof = ooo_segment_offset (f, s);
+ s_eof = ooo_segment_end_offset (f, s);
+
+ /* No overlap, add before current segment */
+ if (end_offset < s_sof)
+ {
+ new_s = ooo_segment_new (f, position, length);
+ new_index = new_s - f->ooo_segments;
+
+ /* Pool might've moved, get segment again */
+ s = pool_elt_at_index (f->ooo_segments, s_index);
+
+ if (s->prev != OOO_SEGMENT_INVALID_INDEX)
+ {
+ new_s->prev = s->prev;
+
+ prev = pool_elt_at_index (f->ooo_segments, new_s->prev);
+ prev->next = new_index;
+ }
+ else
+ {
+ /* New head */
+ f->ooos_list_head = new_index;
+ }
+
+ new_s->next = s - f->ooo_segments;
+ s->prev = new_index;
+ f->ooos_newest = new_index;
+ return;
+ }
+ /* No overlap, add after current segment */
+ else if (s_eof < offset)
+ {
+ new_s = ooo_segment_new (f, position, length);
+ new_index = new_s - f->ooo_segments;
+
+ /* Pool might've moved, get segment again */
+ s = pool_elt_at_index (f->ooo_segments, s_index);
+
+ if (s->next != OOO_SEGMENT_INVALID_INDEX)
+ {
+ new_s->next = s->next;
+
+ next = pool_elt_at_index (f->ooo_segments, new_s->next);
+ next->prev = new_index;
+ }
+
+ new_s->prev = s - f->ooo_segments;
+ s->next = new_index;
+ f->ooos_newest = new_index;
+
+ return;
+ }
+
+ /*
+ * Merge needed
+ */
+
+ /* Merge at head */
+ if (offset <= s_sof)
+ {
+ /* If we have a previous, check if we overlap */
+ if (s->prev != OOO_SEGMENT_INVALID_INDEX)
+ {
+ prev = pool_elt_at_index (f->ooo_segments, s->prev);
+
+ /* New segment merges prev and current. Remove previous and
+ * update position of current. */
+ if (ooo_segment_end_offset (f, prev) >= offset)
+ {
+ s->fifo_position = prev->fifo_position;
+ s->length = s_eof - ooo_segment_offset (f, prev);
+ ooo_segment_del (f, s->prev);
+ }
+ }
+ else
+ {
+ s->fifo_position = position;
+ s->length = s_eof - ooo_segment_offset (f, s);
+ }
+
+ /* The new segment's tail may cover multiple smaller ones */
+ if (s_eof < end_offset)
+ {
+ /* Remove segments completely covered */
+ it = (s->next != OOO_SEGMENT_INVALID_INDEX) ?
+ pool_elt_at_index (f->ooo_segments, s->next) : 0;
+ while (it && ooo_segment_end_offset (f, it) < end_offset)
+ {
+ next = (it->next != OOO_SEGMENT_INVALID_INDEX) ?
+ pool_elt_at_index (f->ooo_segments, it->next) : 0;
+ ooo_segment_del (f, it - f->ooo_segments);
+ it = next;
+ }
+
+ /* Update length. Segment's start might have changed. */
+ s->length = end_offset - ooo_segment_offset (f, s);
+
+ /* If partial overlap with last, merge */
+ if (it && ooo_segment_offset (f, it) < end_offset)
+ {
+ s->length +=
+ it->length - (ooo_segment_offset (f, it) - end_offset);
+ ooo_segment_del (f, it - f->ooo_segments);
+ }
+ }
+ }
+ /* Last but overlapping previous */
+ else if (s_eof <= end_offset)
+ {
+ s->length = end_offset - ooo_segment_offset (f, s);
+ }
+ /* New segment completely covered by current one */
+ else
+ {
+ /* Do Nothing */
+ }
+
+ /* Most recently updated segment */
+ f->ooos_newest = s - f->ooo_segments;
+}
+
+/**
+ * Removes segments that can now be enqueued because the fifo's tail has
+ * advanced. Returns the number of bytes added to tail.
+ */
+static int
+ooo_segment_try_collect (svm_fifo_t * f, u32 n_bytes_enqueued)
+{
+ ooo_segment_t *s;
+ u32 index, bytes = 0, diff;
+
+ s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
+
+ /* If last tail update overlaps one/multiple ooo segments, remove them */
+ diff = (f->nitems + f->tail - s->fifo_position) % f->nitems;
+ while (0 < diff && diff < n_bytes_enqueued)
+ {
+ /* Segment end is beyond the tail. Advance tail and be done */
+ if (diff < s->length)
+ {
+ f->tail += s->length - diff;
+ f->tail %= f->nitems;
+ break;
+ }
+ /* If we have next go on */
+ else if (s->next != OOO_SEGMENT_INVALID_INDEX)
+ {
+ index = s - f->ooo_segments;
+ s = pool_elt_at_index (f->ooo_segments, s->next);
+ diff = (f->nitems + f->tail - s->fifo_position) % f->nitems;
+ ooo_segment_del (f, index);
+ }
+ /* End of search */
+ else
+ {
+ break;
+ }
+ }
+
+ /* If tail is adjacent to an ooo segment, 'consume' it */
+ if (diff == 0)
+ {
+ bytes = ((f->nitems - f->cursize) >= s->length) ? s->length :
+ f->nitems - f->cursize;
+
+ f->tail += bytes;
+ f->tail %= f->nitems;
+
+ ooo_segment_del (f, s - f->ooo_segments);
+ }
+
+ return bytes;
+}
+
+static int
+svm_fifo_enqueue_internal (svm_fifo_t * f,
+ int pid, u32 max_bytes, u8 * copy_from_here)
+{
+ u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
+ u32 cursize, nitems;
+
+ if (PREDICT_FALSE (f->cursize == f->nitems))
+ return -2; /* fifo stuffed */
+
+ /* read cursize, which can only decrease while we're working */
+ cursize = f->cursize;
+ nitems = f->nitems;
+
+ /* Number of bytes we're going to copy */
+ total_copy_bytes = (nitems - cursize) < max_bytes ?
+ (nitems - cursize) : max_bytes;
+
+ if (PREDICT_TRUE (copy_from_here != 0))
+ {
+ /* Number of bytes in first copy segment */
+ first_copy_bytes = ((nitems - f->tail) < total_copy_bytes)
+ ? (nitems - f->tail) : total_copy_bytes;
+
+ clib_memcpy (&f->data[f->tail], copy_from_here, first_copy_bytes);
+ f->tail += first_copy_bytes;
+ f->tail = (f->tail == nitems) ? 0 : f->tail;
+
+ /* Number of bytes in second copy segment, if any */
+ second_copy_bytes = total_copy_bytes - first_copy_bytes;
+ if (second_copy_bytes)
+ {
+ clib_memcpy (&f->data[f->tail], copy_from_here + first_copy_bytes,
+ second_copy_bytes);
+ f->tail += second_copy_bytes;
+ f->tail = (f->tail == nitems) ? 0 : f->tail;
+ }
+ }
+ else
+ {
+ /* Account for a zero-copy enqueue done elsewhere */
+ ASSERT (max_bytes <= (nitems - cursize));
+ f->tail += max_bytes;
+ f->tail = f->tail % nitems;
+ total_copy_bytes = max_bytes;
+ }
+
+ /* Any out-of-order segments to collect? */
+ if (PREDICT_FALSE (f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX))
+ total_copy_bytes += ooo_segment_try_collect (f, total_copy_bytes);
+
+ /* Atomically increase the queue length */
+ __sync_fetch_and_add (&f->cursize, total_copy_bytes);
+
+ return (total_copy_bytes);
+}
+
+int
+svm_fifo_enqueue_nowait (svm_fifo_t * f,
+ int pid, u32 max_bytes, u8 * copy_from_here)
+{
+ return svm_fifo_enqueue_internal (f, pid, max_bytes, copy_from_here);
+}
+
+/** Enqueue a future segment.
+ * Two choices: either copies the entire segment, or copies nothing
+ * Returns 0 of the entire segment was copied
+ * Returns -1 if none of the segment was copied due to lack of space
+ */
+
+static int
+svm_fifo_enqueue_with_offset_internal2 (svm_fifo_t * f,
+ int pid,
+ u32 offset,
+ u32 required_bytes,
+ u8 * copy_from_here)
+{
+ u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
+ u32 cursize, nitems;
+ u32 tail_plus_offset;
+
+ ASSERT (offset > 0);
+
+ /* read cursize, which can only decrease while we're working */
+ cursize = f->cursize;
+ nitems = f->nitems;
+
+ /* Will this request fit? */
+ if ((required_bytes + offset) > (nitems - cursize))
+ return -1;
+
+ ooo_segment_add (f, offset, required_bytes);
+
+ /* Number of bytes we're going to copy */
+ total_copy_bytes = required_bytes;
+ tail_plus_offset = (f->tail + offset) % nitems;
+
+ /* Number of bytes in first copy segment */
+ first_copy_bytes = ((nitems - tail_plus_offset) < total_copy_bytes)
+ ? (nitems - tail_plus_offset) : total_copy_bytes;
+
+ clib_memcpy (&f->data[tail_plus_offset], copy_from_here, first_copy_bytes);
+
+ /* Number of bytes in second copy segment, if any */
+ second_copy_bytes = total_copy_bytes - first_copy_bytes;
+ if (second_copy_bytes)
+ {
+ tail_plus_offset += first_copy_bytes;
+ tail_plus_offset %= nitems;
+
+ ASSERT (tail_plus_offset == 0);
+
+ clib_memcpy (&f->data[tail_plus_offset],
+ copy_from_here + first_copy_bytes, second_copy_bytes);
+ }
+
+ return (0);
+}
+
+
+int
+svm_fifo_enqueue_with_offset (svm_fifo_t * f,
+ int pid,
+ u32 offset,
+ u32 required_bytes, u8 * copy_from_here)
+{
+ return svm_fifo_enqueue_with_offset_internal2
+ (f, pid, offset, required_bytes, copy_from_here);
+}
+
+
+static int
+svm_fifo_dequeue_internal2 (svm_fifo_t * f,
+ int pid, u32 max_bytes, u8 * copy_here)
+{
+ u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
+ u32 cursize, nitems;
+
+ if (PREDICT_FALSE (f->cursize == 0))
+ return -2; /* nothing in the fifo */
+
+ /* read cursize, which can only increase while we're working */
+ cursize = f->cursize;
+ nitems = f->nitems;
+
+ /* Number of bytes we're going to copy */
+ total_copy_bytes = (cursize < max_bytes) ? cursize : max_bytes;
+
+ if (PREDICT_TRUE (copy_here != 0))
+ {
+ /* Number of bytes in first copy segment */
+ first_copy_bytes = ((nitems - f->head) < total_copy_bytes)
+ ? (nitems - f->head) : total_copy_bytes;
+ clib_memcpy (copy_here, &f->data[f->head], first_copy_bytes);
+ f->head += first_copy_bytes;
+ f->head = (f->head == nitems) ? 0 : f->head;
+
+ /* Number of bytes in second copy segment, if any */
+ second_copy_bytes = total_copy_bytes - first_copy_bytes;
+ if (second_copy_bytes)
+ {
+ clib_memcpy (copy_here + first_copy_bytes,
+ &f->data[f->head], second_copy_bytes);
+ f->head += second_copy_bytes;
+ f->head = (f->head == nitems) ? 0 : f->head;
+ }
+ }
+ else
+ {
+ /* Account for a zero-copy dequeue done elsewhere */
+ ASSERT (max_bytes <= cursize);
+ f->head += max_bytes;
+ f->head = f->head % nitems;
+ cursize -= max_bytes;
+ total_copy_bytes = max_bytes;
+ }
+
+ __sync_fetch_and_sub (&f->cursize, total_copy_bytes);
+
+ return (total_copy_bytes);
+}
+
+int
+svm_fifo_dequeue_nowait (svm_fifo_t * f,
+ int pid, u32 max_bytes, u8 * copy_here)
+{
+ return svm_fifo_dequeue_internal2 (f, pid, max_bytes, copy_here);
+}
+
+int
+svm_fifo_peek (svm_fifo_t * f, int pid, u32 offset, u32 max_bytes,
+ u8 * copy_here)
+{
+ u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
+ u32 cursize, nitems;
+
+ if (PREDICT_FALSE (f->cursize == 0))
+ return -2; /* nothing in the fifo */
+
+ /* read cursize, which can only increase while we're working */
+ cursize = f->cursize;
+ nitems = f->nitems;
+
+ /* Number of bytes we're going to copy */
+ total_copy_bytes = (cursize < max_bytes) ? cursize : max_bytes;
+
+ if (PREDICT_TRUE (copy_here != 0))
+ {
+ /* Number of bytes in first copy segment */
+ first_copy_bytes =
+ ((nitems - f->head) < total_copy_bytes) ?
+ (nitems - f->head) : total_copy_bytes;
+ clib_memcpy (copy_here, &f->data[f->head], first_copy_bytes);
+
+ /* Number of bytes in second copy segment, if any */
+ second_copy_bytes = total_copy_bytes - first_copy_bytes;
+ if (second_copy_bytes)
+ {
+ clib_memcpy (copy_here + first_copy_bytes, &f->data[0],
+ second_copy_bytes);
+ }
+ }
+ return total_copy_bytes;
+}
+
+int
+svm_fifo_dequeue_drop (svm_fifo_t * f, int pid, u32 max_bytes)
+{
+ u32 total_drop_bytes, first_drop_bytes, second_drop_bytes;
+ u32 cursize, nitems;
+
+ if (PREDICT_FALSE (f->cursize == 0))
+ return -2; /* nothing in the fifo */
+
+ /* read cursize, which can only increase while we're working */
+ cursize = f->cursize;
+ nitems = f->nitems;
+
+ /* Number of bytes we're going to drop */
+ total_drop_bytes = (cursize < max_bytes) ? cursize : max_bytes;
+
+ /* Number of bytes in first copy segment */
+ first_drop_bytes =
+ ((nitems - f->head) < total_drop_bytes) ?
+ (nitems - f->head) : total_drop_bytes;
+ f->head += first_drop_bytes;
+ f->head = (f->head == nitems) ? 0 : f->head;
+
+ /* Number of bytes in second drop segment, if any */
+ second_drop_bytes = total_drop_bytes - first_drop_bytes;
+ if (second_drop_bytes)
+ {
+ f->head += second_drop_bytes;
+ f->head = (f->head == nitems) ? 0 : f->head;
+ }
+
+ __sync_fetch_and_sub (&f->cursize, total_drop_bytes);
+
+ return total_drop_bytes;
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */