}
static inline uword
-fsh_virtual_mem (fifo_segment_header_t * fsh)
+fs_virtual_mem (fifo_segment_t *fs)
{
+ fifo_segment_header_t *fsh = fs->h;
fifo_segment_slice_t *fss;
uword total_vm = 0;
int i;
- for (i = 0; i < fsh->n_slices; i++)
+ for (i = 0; i < fs->n_slices; i++)
{
fss = fsh_slice_get (fsh, i);
total_vm += clib_atomic_load_relax_n (&fss->virtual_mem);
fss->virtual_mem += n_bytes;
}
-static inline void
-fss_chunk_freelist_lock (fifo_segment_slice_t *fss)
+static inline int
+fss_chunk_fl_index_is_valid (fifo_segment_slice_t *fss, u32 fl_index)
{
- u32 free = 0;
- while (!clib_atomic_cmp_and_swap_acq_relax_n (&fss->chunk_lock, &free, 1, 0))
- {
- /* atomic load limits number of compare_exchange executions */
- while (clib_atomic_load_relax_n (&fss->chunk_lock))
- CLIB_PAUSE ();
- /* on failure, compare_exchange writes (*p)->lock into free */
- free = 0;
- }
+ return (fl_index < FS_CHUNK_VEC_LEN);
}
-static inline void
-fss_chunk_freelist_unlock (fifo_segment_slice_t *fss)
-{
- /* Make sure all reads/writes are complete before releasing the lock */
- clib_atomic_release (&fss->chunk_lock);
-}
+#define FS_CL_HEAD_MASK 0xFFFFFFFFFFFF
+#define FS_CL_HEAD_TMASK 0xFFFF000000000000
+#define FS_CL_HEAD_TINC (1ULL << 48)
-static inline int
-fss_chunk_fl_index_is_valid (fifo_segment_slice_t * fss, u32 fl_index)
+static svm_fifo_chunk_t *
+fss_chunk_free_list_head (fifo_segment_header_t *fsh,
+ fifo_segment_slice_t *fss, u32 fl_index)
{
- return (fl_index < FS_CHUNK_VEC_LEN);
+ fs_sptr_t headsp = clib_atomic_load_relax_n (&fss->free_chunks[fl_index]);
+ return fs_chunk_ptr (fsh, headsp & FS_CL_HEAD_MASK);
}
static void
fifo_segment_slice_t *fss, u32 fl_index,
svm_fifo_chunk_t *c)
{
- fss_chunk_freelist_lock (fss);
- c->next = fss->free_chunks[fl_index];
- fss->free_chunks[fl_index] = fs_chunk_sptr (fsh, c);
- fss_chunk_freelist_unlock (fss);
+ fs_sptr_t old_head, new_head, csp;
+
+ csp = fs_chunk_sptr (fsh, c);
+ ASSERT (csp <= FS_CL_HEAD_MASK);
+ old_head = clib_atomic_load_acq_n (&fss->free_chunks[fl_index]);
+
+ do
+ {
+ c->next = old_head & FS_CL_HEAD_MASK;
+ new_head = csp + ((old_head + FS_CL_HEAD_TINC) & FS_CL_HEAD_TMASK);
+ }
+ while (!__atomic_compare_exchange (&fss->free_chunks[fl_index], &old_head,
+ &new_head, 0 /* weak */, __ATOMIC_RELEASE,
+ __ATOMIC_ACQUIRE));
}
static void
fifo_segment_slice_t *fss, u32 fl_index,
svm_fifo_chunk_t *head, svm_fifo_chunk_t *tail)
{
- fss_chunk_freelist_lock (fss);
- tail->next = fss->free_chunks[fl_index];
- fss->free_chunks[fl_index] = fs_chunk_sptr (fsh, head);
- fss_chunk_freelist_unlock (fss);
+ fs_sptr_t old_head, new_head, headsp;
+
+ headsp = fs_chunk_sptr (fsh, head);
+ ASSERT (headsp <= FS_CL_HEAD_MASK);
+ old_head = clib_atomic_load_acq_n (&fss->free_chunks[fl_index]);
+
+ do
+ {
+ tail->next = old_head & FS_CL_HEAD_MASK;
+ new_head = headsp + ((old_head + FS_CL_HEAD_TINC) & FS_CL_HEAD_TMASK);
+ }
+ while (!__atomic_compare_exchange (&fss->free_chunks[fl_index], &old_head,
+ &new_head, 0 /* weak */, __ATOMIC_RELEASE,
+ __ATOMIC_ACQUIRE));
}
static svm_fifo_chunk_t *
fss_chunk_free_list_pop (fifo_segment_header_t *fsh, fifo_segment_slice_t *fss,
u32 fl_index)
{
+ fs_sptr_t old_head, new_head;
svm_fifo_chunk_t *c;
ASSERT (fss_chunk_fl_index_is_valid (fss, fl_index));
- fss_chunk_freelist_lock (fss);
+ old_head = clib_atomic_load_acq_n (&fss->free_chunks[fl_index]);
- if (!fss->free_chunks[fl_index])
+ /* Lock-free stacks are affected by ABA if a side allocates a chunk and
+ * shortly thereafter frees it. To circumvent that, reuse the upper bits
+ * of the head of the list shared pointer, i.e., offset to where the chunk
+ * is, as a tag. The tag is incremented with each push/pop operation and
+ * therefore collisions can only happen if an element is popped and pushed
+ * exactly after a complete wrap of the tag (16 bits). It's unlikely either
+ * of the sides will be descheduled for that long */
+ do
{
- fss_chunk_freelist_unlock (fss);
- return 0;
+ if (!(old_head & FS_CL_HEAD_MASK))
+ return 0;
+ c = fs_chunk_ptr (fsh, old_head & FS_CL_HEAD_MASK);
+ new_head = c->next + ((old_head + FS_CL_HEAD_TINC) & FS_CL_HEAD_TMASK);
}
-
- c = fs_chunk_ptr (fsh, fss->free_chunks[fl_index]);
- fss->free_chunks[fl_index] = c->next;
-
- fss_chunk_freelist_unlock (fss);
+ while (!__atomic_compare_exchange (&fss->free_chunks[fl_index], &old_head,
+ &new_head, 0 /* weak */, __ATOMIC_RELEASE,
+ __ATOMIC_ACQUIRE));
return c;
}
if (data_bytes <= fss_fl_chunk_bytes (fss) + n_free)
{
u32 min_size = FIFO_SEGMENT_MIN_FIFO_SIZE;
-
+ if (n_free < min_size)
+ goto done;
batch = (data_bytes - fss_fl_chunk_bytes (fss)) / min_size;
batch = clib_min (batch + 1, n_free / min_size);
if (fsh_try_alloc_chunk_batch (fsh, fss, 0, batch))
return f;
}
+svm_fifo_t *
+fifo_segment_duplicate_fifo (fifo_segment_t *fs, svm_fifo_t *f)
+{
+ svm_fifo_t *nf = fs_fifo_alloc (fs, 0);
+ clib_memcpy (nf, f, sizeof (*f));
+ return nf;
+}
+
/**
* Free fifo allocated in fifo segment
*/
return (u8 *) f->shr - (u8 *) f->fs_hdr;
}
+svm_fifo_chunk_t *
+fifo_segment_alloc_chunk_w_slice (fifo_segment_t *fs, u32 slice_index,
+ u32 chunk_size)
+{
+ fifo_segment_header_t *fsh = fs->h;
+ fifo_segment_slice_t *fss;
+
+ fss = fsh_slice_get (fsh, slice_index);
+ return fsh_try_alloc_chunk (fsh, fss, chunk_size);
+}
+
+void
+fifo_segment_collect_chunk (fifo_segment_t *fs, u32 slice_index,
+ svm_fifo_chunk_t *c)
+{
+ fsh_collect_chunks (fs->h, slice_index, c);
+}
+
+uword
+fifo_segment_chunk_offset (fifo_segment_t *fs, svm_fifo_chunk_t *c)
+{
+ return (u8 *) c - (u8 *) fs->h;
+}
+
svm_msg_q_t *
fifo_segment_msg_q_alloc (fifo_segment_t *fs, u32 mq_index,
svm_msg_q_cfg_t *cfg)
{
for (i = 0; i < FS_CHUNK_VEC_LEN; i++)
{
- c = fs_chunk_ptr (fsh, fss->free_chunks[i]);
+ c = fss_chunk_free_list_head (fsh, fss, i);
if (c == 0)
continue;
if (fl_index >= FS_CHUNK_VEC_LEN)
return 0;
- c = fs_chunk_ptr (fsh, fss->free_chunks[fl_index]);
+ c = fss_chunk_free_list_head (fsh, fss, fl_index);
if (c == 0)
return 0;
return fs->h->max_byte_index - fs->h->n_reserved_bytes;
}
-u8
-fsh_has_reached_mem_limit (fifo_segment_header_t * fsh)
+static u8
+fs_has_reached_mem_limit (fifo_segment_t *fs)
{
- return (fsh->flags & FIFO_SEGMENT_F_MEM_LIMIT) ? 1 : 0;
+ return (fs->flags & FIFO_SEGMENT_F_MEM_LIMIT) ? 1 : 0;
}
-void
-fsh_reset_mem_limit (fifo_segment_header_t * fsh)
+static void
+fs_reset_mem_limit (fifo_segment_t *fs)
{
- fsh->flags &= ~FIFO_SEGMENT_F_MEM_LIMIT;
+ fs->flags &= ~FIFO_SEGMENT_F_MEM_LIMIT;
}
void *
}
fifo_segment_mem_status_t
-fifo_segment_determine_status (fifo_segment_header_t * fsh, u8 usage)
+fifo_segment_determine_status (fifo_segment_t *fs, u8 usage)
{
- if (!fsh->high_watermark || !fsh->low_watermark)
+ if (!fs->high_watermark || !fs->low_watermark)
return MEMORY_PRESSURE_NO_PRESSURE;
/* once the no-memory is detected, the status continues
* until memory usage gets below the high watermark
*/
- if (fsh_has_reached_mem_limit (fsh))
+ if (fs_has_reached_mem_limit (fs))
{
- if (usage >= fsh->high_watermark)
+ if (usage >= fs->high_watermark)
return MEMORY_PRESSURE_NO_MEMORY;
else
- fsh_reset_mem_limit (fsh);
+ fs_reset_mem_limit (fs);
}
- if (usage >= fsh->high_watermark)
+ if (usage >= fs->high_watermark)
return MEMORY_PRESSURE_HIGH_PRESSURE;
- else if (usage >= fsh->low_watermark)
+ else if (usage >= fs->low_watermark)
return MEMORY_PRESSURE_LOW_PRESSURE;
return MEMORY_PRESSURE_NO_PRESSURE;
fifo_segment_mem_status_t
fifo_segment_get_mem_status (fifo_segment_t * fs)
{
- fifo_segment_header_t *fsh = fs->h;
u8 usage = fifo_segment_get_mem_usage (fs);
- return fifo_segment_determine_status (fsh, usage);
+ return fifo_segment_determine_status (fs, usage);
}
u8 *
fss = fsh_slice_get (fsh, slice_index);
for (i = 0; i < FS_CHUNK_VEC_LEN; i++)
{
- c = fs_chunk_ptr (fsh, fss->free_chunks[i]);
+ c = fss_chunk_free_list_head (fsh, fss, i);
if (c == 0 && fss->num_chunks[i] == 0)
continue;
count = 0;
in_use = fifo_segment_size (fs) - est_free_seg_bytes - tracked_cached_bytes;
usage = (100.0 * in_use) / allocated;
mem_st = fifo_segment_get_mem_status (fs);
- virt = fsh_virtual_mem (fsh);
+ virt = fs_virtual_mem (fs);
reserved = fsh->n_reserved_bytes;
s = format (s, "\n%Useg free bytes: %U (%lu) estimated: %U (%lu) reserved:"
Code Review / vpp.git / blobdiff