diff options
Diffstat (limited to 'src/H5Cprivate.h')
| -rw-r--r-- | src/H5Cprivate.h | 58 |
1 files changed, 50 insertions, 8 deletions
diff --git a/src/H5Cprivate.h b/src/H5Cprivate.h index 28eacf2..3408839 100644 --- a/src/H5Cprivate.h +++ b/src/H5Cprivate.h @@ -1066,9 +1066,9 @@ typedef int H5C_ring_t; * * is_read_only: Boolean flag that is only meaningful if is_protected is * TRUE. In this circumstance, it indicates whether the - * entry has been protected read only, or read/write. + * entry has been protected read-only, or read/write. * - * If the entry has been protected read only (i.e. is_protected + * If the entry has been protected read-only (i.e. is_protected * and is_read_only are both TRUE), we allow the entry to be * protected more than once. * @@ -1078,7 +1078,7 @@ typedef int H5C_ring_t; * the entry is actually unprotected. * * ro_ref_count: Integer field used to maintain a count of the number of - * outstanding read only protects on this entry. This field + * outstanding read-only protects on this entry. This field * must be zero whenever either is_protected or is_read_only * are TRUE. * @@ -1458,13 +1458,13 @@ typedef int H5C_ring_t; * the load of a cache image block, although other scenarios * are contemplated for the use of this feature. Note that * unlike the usual prefetch situation, this means that a - * pre fetched entry can be dirty, and/or can be a party to + * prefetched entry can be dirty, and/or can be a party to * flush dependency relationship(s). This complicates matters * somewhat. * - * The essential feature of a pre-fetched entry is that it + * The essential feature of a prefetched entry is that it * consists only of a buffer containing the on disk image of - * the entry. Thus it must be deserialized before it can + * the entry. Thus it must be deserialized before it can * be passed back to the library on a protect call. This * task is handled by H5C_deserialized_prefetched_entry(). * In essence, this routine calls the deserialize callback @@ -1475,7 +1475,7 @@ typedef int H5C_ring_t; * * Further, if the prefetched entry is a flush dependency parent, * all its flush dependency children (which must also be - * pre-fetched entries), must be tranfered to the new cache + * prefetched entries), must be tranfered to the new cache * entry returned by the deserailization callback. * * Finally, if the prefetched entry is a flush dependency child, @@ -1511,6 +1511,46 @@ typedef int H5C_ring_t; * * This field must be zero if prefetched is FALSE. * + * prefetched_dirty: Boolean field that must be set to FALSE unless the + * following conditions hold: + * + * 1) The file has been opened R/O. + * + * 2) The entry is either a prefetched entry, or was + * re-constructed from a prefetched entry. + * + * 3) The base prefetched entry was marked dirty. + * + * This field exists to solve the following problem with + * files containing cache images that are opened R/O. + * + * If the cache image contains a dirty entry, that entry + * must be marked clean when it is inserted into the cache + * in the read-only case, as otherwise the metadata cache + * will attempt to flush it on file close -- which is poor + * form in the read-only case. + * + * However, since the entry is marked clean, it is possible + * that the metadata cache will evict it if the size of the + * metadata in the file exceeds the size of the metadata cache, + * and the application visits much of this data. + * + * If this happens, and the metadata cache is then asked for + * this entry, it will attempt to read it from file, and will + * obtain either obsolete or invalid data depending on whether + * the entry has ever been written to it assigned location in + * the file. + * + * With this background, the purpose of this field should be + * obvious -- when set, it allows the eviction candidate + * selection code to skip over the entry, thus avoiding the + * issue. + * + * Since the issue only arises in the R/O case, there is + * no possible interaction with SWMR. There are also + * potential interactions with Evict On Close -- at present, + * we deal with this by disabling EOC in the R/O case. + * * serialization_count: Integer field used to maintain a count of the * number of times each entry is serialized during cache * serialization. While no entry should be serialized more than @@ -1627,6 +1667,7 @@ typedef struct H5C_cache_entry_t { hbool_t prefetched; int prefetch_type_id; int32_t age; + hbool_t prefetched_dirty; #ifndef NDEBUG /* debugging field */ int serialization_count; @@ -2259,7 +2300,6 @@ H5_DLL herr_t H5C_set_trace_file_ptr(H5C_t *cache_ptr, FILE *trace_file_ptr); H5_DLL herr_t H5C_stats(H5C_t *cache_ptr, const char *cache_name, hbool_t display_detailed_stats); H5_DLL void H5C_stats__reset(H5C_t *cache_ptr); -H5_DLL herr_t H5C_dump_cache(H5C_t *cache_ptr, const char *cache_name); H5_DLL herr_t H5C_unpin_entry(void *thing); H5_DLL herr_t H5C_destroy_flush_dependency(void *parent_thing, void *child_thing); H5_DLL herr_t H5C_unprotect(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *thing, @@ -2289,6 +2329,8 @@ H5_DLL herr_t H5C_mark_entries_as_clean(H5F_t *f, hid_t dxpl_id, unsigned ce_arr #endif /* H5_HAVE_PARALLEL */ #ifndef NDEBUG /* debugging functions */ +H5_DLL herr_t H5C_dump_cache(H5C_t *cache_ptr, const char *cache_name); +H5_DLL herr_t H5C_dump_cache_LRU(H5C_t *cache_ptr, const char *cache_name); H5_DLL hbool_t H5C_get_serialization_in_progress(const H5C_t *cache_ptr); H5_DLL hbool_t H5C_cache_is_clean(const H5C_t *cache_ptr, H5C_ring_t inner_ring); H5_DLL herr_t H5C_dump_cache_skip_list(H5C_t *cache_ptr, char *calling_fcn); |