diff options
Diffstat (limited to 'src/H5Cprivate.h')
| -rw-r--r-- | src/H5Cprivate.h | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/src/H5Cprivate.h b/src/H5Cprivate.h index 3cd74c1..2a3efc9 100644 --- a/src/H5Cprivate.h +++ b/src/H5Cprivate.h @@ -1115,6 +1115,60 @@ typedef herr_t (*H5C_log_flush_func_t)(H5C_t *cache_ptr, haddr_t addr, /**************************************************************************** * + * H5C_ring_t & associated #defines + * + * The metadata cache uses the concept of rings to order the flushes of + * classes of entries. In this arrangement, each entry in the cache is + * assigned to a ring, and on flush, the members of the outermost ring + * are flushed first, followed by the next outermost, and so on with the + * members of the innermost ring being flushed last. + * + * Note that flush dependencies are used to order flushes within rings. + * + * Note also that at the conceptual level, rings are argueably superfluous, + * as a similar effect could be obtained via the flush dependency mechanism. + * However, this would require all entries in the cache to participate in a + * flush dependency -- with the implied setup and takedown overhead and + * added complexity. Further, the flush ordering between rings need only + * be enforced on flush operations, and thus the use of flush dependencies + * instead would apply unecessary constraints on flushes under normal + * operating circumstances. + * + * As of this writing, all metadata entries pretaining to data sets and + * groups must be flushed first, and are thus assigned to the outermost + * ring. + * + * Free space managers managing file space must be flushed next, + * and are assigned to the second outermost ring. + * + * The object header and associated chunks used to implement superblock + * extension messages must be flushed next, and are thus assigned to + * the third outermost ring. + * + * The superblock proper must be flushed last, and is thus assigned to + * the innermost ring. + * + * The H5C_ring_t and the associated #defines below are used to define + * the rings. Each entry must be assigned to the appropriate ring on + * insertion or protect. + * + * Note that H5C_ring_t was originally an enumerated type. It was + * converted to an integer and a set of #defines for convenience in + * debugging. + */ + +#define H5C_RING_UNDEFINED 0 /* shouldn't appear in the cache */ +#define H5C_RING_USER 1 /* outermost ring */ +#define H5C_RING_FSM 2 +#define H5C_RING_SBE 4 /* temporarily merged with H5C_RING_SB */ +#define H5C_RING_SB 4 /* innermost ring */ +#define H5C_RING_NTYPES 5 + +typedef int H5C_ring_t; + + +/**************************************************************************** + * * structure H5C_cache_entry_t * * Instances of the H5C_cache_entry_t structure are used to store cache @@ -1376,6 +1430,25 @@ typedef herr_t (*H5C_log_flush_func_t)(H5C_t *cache_ptr, haddr_t addr, * is in the process of being flushed and destroyed. * * + * Fields supporting rings for flush ordering: + * + * All entries in the metadata cache are assigned to a ring. On cache + * flush, all entries in the outermost ring are flushed first, followed + * by all members of the next outermost ring, and so on until the + * innermost ring is flushed. Note that this ordering is ONLY applied + * in flush and serialize calls. Rings are ignored during normal operations + * in which entries are flushed as directed by the replacement policy. + * + * See the header comment on H5C_ring_t above for further details. + * + * Note that flush dependencies (see below) are used to order flushes + * within rings. Unlike rings, flush dependencies are applied to ALL + * writes, not just those triggered by flush or serialize calls. + * + * ring: Instance of H5C_ring_t indicating the ring to which this + * entry is assigned. + * + * * Fields supporting the 'flush dependency' feature: * * Entries in the cache may have a 'flush dependency' on another entry in the @@ -1543,6 +1616,9 @@ typedef struct H5C_cache_entry_t { hbool_t flush_in_progress; hbool_t destroy_in_progress; + /* fields supporting rings for purposes of flush ordering */ + H5C_ring_t ring; + /* fields supporting the 'flush dependency' feature: */ struct H5C_cache_entry_t * flush_dep_parent; uint64_t child_flush_dep_height_rc[H5C__NUM_FLUSH_DEP_HEIGHTS]; @@ -1917,6 +1993,7 @@ H5_DLL herr_t H5C_validate_resize_config(H5C_auto_size_ctl_t *config_ptr, unsigned int tests); H5_DLL herr_t H5C_ignore_tags(H5C_t *cache_ptr); H5_DLL void H5C_retag_copied_metadata(H5C_t *cache_ptr, haddr_t metadata_tag); +H5_DLL herr_t H5C_get_entry_ring(const H5F_t *f, haddr_t addr, H5C_ring_t *ring); #ifdef H5_HAVE_PARALLEL H5_DLL herr_t H5C_apply_candidate_list(H5F_t *f, hid_t dxpl_id, |