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Nathan Hjelm committed 975600e

add notes on btl segments

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  • Parent commits c8949be

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File ompi/mca/btl/btl.h

 /**
  * Describes a region/segment of memory that is addressable 
  * by an BTL.
+ *
+ * Note: In many cases the alloc and prepare methods of BTLs
+ * do not return a mca_btl_base_segment_t but instead return a
+ * subclass. Extreme care should be used when modifying
+ * BTL segments to prevent overwriting internal BTL data.
+ *
+ * All BTLs MUST use base segments when calling registered
+ * Callbacks.
+ *
+ * BTL MUST use mca_btl_base_segment_t or a subclass and
+ * MUST store their segment length in btl_seg_size. BTLs
+ * MIST specify a segment no larger than MCA_BTL_SEG_MAX_SIZE.
+ *
  */
 
 struct mca_btl_base_segment_t {
 #define MCA_BTL_DES_MAX_SEGMENTS 16
 
 /**
- * Maximum size of a btl segment (NTH: does it really save us anything
+ * Maximum size of a BTL segment (NTH: does it really save us anything
  * to hardcode this?)
  */
 #define MCA_BTL_SEG_MAX_SIZE 256