start work on enabling VMCORE and adding support in ustd

[ust.git] / ustd / lowlevel.c

diff --git a/ustd/lowlevel.c b/ustd/lowlevel.c
new file mode 100644 (file)
index 0000000..f386089
--- /dev/null
+++ b/ustd/lowlevel.c
@@ -0,0 +1,50 @@
+#include "tracer.h"
+#include "ustd.h"
+#include "localerr.h"
+
+#define USTD_BUFFER_TRUNC(offset, bufinfo) \
+       ((offset) & (~(((bufinfo)->subbuf_size*(bufinfo)->n_subbufs)-1)))
+
+void finish_consuming_dead_subbuffer(struct buffer_info *buf)
+{
+       struct ltt_channel_buf_struct *ltt_buf = buf->bufstruct_mem;
+
+       long write_offset = local_read(&ltt_buf->offset);
+       long consumed_offset = atomic_long_read(&ltt_buf->consumed);
+
+       long i_subbuf;
+
+       DBG("processing died buffer");
+       DBG("consumed offset is %ld", consumed_offset);
+       DBG("write offset is %ld", write_offset);
+
+       long first_subbuf = write_offset / buf->subbuf_size;
+       long last_subbuf = consumed_offset / buf->subbuf_size;
+
+       if(last_subbuf - first_subbuf > buf->n_subbufs) {
+               DBG("an overflow has occurred, nothing can be recovered");
+               return;
+       }
+
+       for(i_subbuf=first_subbuf; ; i_subbuf++, i_subbuf %= buf->n_subbufs) {
+               long commit_count = local_read(&ltt_buf->commit_count[i_subbuf]);
+
+               unsigned long valid_length = buf->subbuf_size;
+               long n_subbufs_order = get_count_order(buf->n_subbufs);
+               long commit_count_mask = (~0UL >> n_subbufs_order);
+
+               /* check if subbuf was fully written */
+               if (((commit_count - buf->subbuf_size) & commit_count_mask)
+                   - (USTD_BUFFER_TRUNC(consumed_offset, buf) >> n_subbufs_order)
+                   != 0) {
+                       struct ltt_subbuffer_header *header = (struct ltt_subbuffer_header *)((char *)buf->mem)+i_subbuf*buf->subbuf_size;
+                       valid_length = buf->subbuf_size - header->lost_size;
+               }
+
+               patient_write(buf->file_fd, buf->mem + i_subbuf * buf->subbuf_size, buf->subbuf_size);
+
+               if(i_subbuf == last_subbuf)
+                       break;
+       }
+}
+