diff options
Diffstat (limited to 'src/H5Cpkg.h')
| -rw-r--r-- | src/H5Cpkg.h | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/src/H5Cpkg.h b/src/H5Cpkg.h index d9a1641..a5eafd6 100644 --- a/src/H5Cpkg.h +++ b/src/H5Cpkg.h @@ -3480,6 +3480,102 @@ if ( ( (entry_ptr) == NULL ) || \ } /* H5C__MOVE_TO_TOP_IN_COLL_LIST */ #endif /* H5_HAVE_PARALLEL */ + +/***************************************/ +/* page buffer hint maintenance macros */ +/***************************************/ + +/*------------------------------------------------------------------------- + * + * Macro: H5C__SET/RESET_PB_READ_HINTS + * + * Purpose: Set or reset the fields needed to provide hints to the + * page buffer so that it can disambuate between speculative + * reads that cross page boundaries and read of metadata + * entries that cross page boundaries without starting on + * a page boundary. This latter behaviour shouldn't happen, + * and the hints allow the page buffer to detect this + * behaviour by un-expected cache client. + * + * See the discussion of the PB hint fields in the header + * comment for H5C_t for further details. + * + * Return: N/A + * + * Programmer: John Mainzer, 3/30/20 + * + * Modifications: + * + * None. + * + *------------------------------------------------------------------------- + */ + +#define H5C__SET_PB_READ_HINTS(cache_ptr, type, may_be_speculative) \ +{ \ + HDassert(cache_ptr); \ + HDassert((cache_ptr)->magic == H5C__H5C_T_MAGIC); \ + HDassert((cache_ptr)->curr_io_type == NULL); \ + HDassert(type); \ + (cache_ptr)->curr_io_type = (type); \ + (cache_ptr)->curr_read_speculative = (may_be_speculative) && \ + ((cache_ptr)->curr_io_type->flags & H5AC__CLASS_SPECULATIVE_LOAD_FLAG); \ + \ +} /* H5C__SET_PB_READ_HINTS() */ + +#define H5C__RESET_PB_READ_HINTS(cache_ptr) \ +{ \ + HDassert(cache_ptr); \ + HDassert((cache_ptr)->magic == H5C__H5C_T_MAGIC); \ + HDassert((cache_ptr)->curr_io_type); \ + (cache_ptr)->curr_io_type = NULL; \ + (cache_ptr)->curr_read_speculative = FALSE; \ + \ +} /* H5C__SET_PB_READ_HINTS() */ + + +/*------------------------------------------------------------------------- + * + * Macro: H5C__SET/RESET_PB_WRITE_HINTS + * + * Purpose: Set or reset the fields needed to provide hints to the + * page buffer so that it can detect un-expected writes of + * metadata entries that cross page boundaries and do not + * start on page boundaries. + * + * See the discussion of the PB hint fields in the header + * comment for H5C_t for further details. + * + * Return: N/A + * + * Programmer: John Mainzer, 3/30/20 + * + * Modifications: + * + * None. + * + *------------------------------------------------------------------------- + */ + +#define H5C__SET_PB_WRITE_HINTS(cache_ptr, type) \ +{ \ + HDassert(cache_ptr); \ + HDassert((cache_ptr)->magic == H5C__H5C_T_MAGIC); \ + HDassert((cache_ptr)->curr_io_type == NULL); \ + HDassert(type); \ + (cache_ptr)->curr_io_type = (type); \ + \ +} /* H5C__SET_PB_WRITE_HINTS() */ + +#define H5C__RESET_PB_WRITE_HINTS(cache_ptr) \ +{ \ + HDassert(cache_ptr); \ + HDassert((cache_ptr)->magic == H5C__H5C_T_MAGIC); \ + HDassert((cache_ptr)->curr_io_type); \ + (cache_ptr)->curr_io_type = NULL; \ + \ +} /* H5C__SET_PB_WRITE_HINTS() */ + /****************************/ /* Package Private Typedefs */ @@ -4413,6 +4509,47 @@ typedef struct H5C_tag_info_t { * managers that are involved in allocating space for free * space managers. * + * Page Buffer Related Fields: + * + * Due to the irregular behavior of some of the cache clients, the + * page buffer occasionally need hints to manage metadta I/O requests + * from the metadata cache -- particularly in the context of VFD SWMR. + * The following fields exist to support this. + * + * + * curr_io_type: Pointer to the instance of H5C_class_t associated with + * the current I/O operation. This pointer should be set + * just before any I/O operation by the metadata cache, and + * re-set to NULL immediately thereafter. + * + * This field exists because the fixed and variable length + * array cache clients allocate numerous entries in a single + * block, and sub-allocate metadata cache entries out of this + * block. The effect of this is to break the invarient, + * normally maintained by the free space managers in paged + * allocation mode, that no entry of less than a page in + * size crosses page boundaries, and that entries of page + * size or greater are page aligned. This in turn causes + * problems for the page buffer -- particularly in VFD SWMR + * mode. + * + * The correct solution is to modify the fixed and variable + * length array cache client to repair this. However, in + * the interrim, this field exists to detect similar + * behaviour elsewhere. + * + * To complicate matters, speculative reads for metadata + * cache entries which must determine their lengths via + * inspection of the on disk image of the entry, may mimic + * the behaviour of the fixed and extensible arrays. Thus + * the curr_io_type is also needed to dis-ambiguate reads. + * + * curr_read_speculative: Boolean flag indicating whether the current + * read request is guaranteed to be of the correct length. + * Field is used to distinguish between the initial and final + * read attempts + * + * * * Statistics collection fields: * @@ -4744,6 +4881,28 @@ typedef struct H5C_tag_info_t { * called successfully. This field is only defined when * NDEBUG is not #defined. * + * curr_io_type: Pointer to the instance of H5C_class_t associated with + * the current I/O operation. This pointer should be set + * just before any I/O operation by the metadata cache, and + * re-set to NULL immediately thereafter. This field is + * only defined when NDEBUG is not #defined. + * + * This field exists because the fixed and variable length + * array cache clients allocate numerous entries in a single + * block, and sub-allocate metadata cache entries out of this + * block. The effect of this is to break the invarient, + * normally maintained by the free space managers in paged + * allocation mode, that no entry of less than a page in + * size crosses page boundaries, and that entries of page + * size or greater are page aligned. This in turn causes + * problems for the page buffer -- particularly in VFD SWMR + * mode. + * + * The correct solution is to modify the fixed and variable + * length array cache client to repair this. However, in + * the interrim, this field exists to detect similar + * behaviour elsewhere. + * ****************************************************************************/ struct H5C_t { uint32_t magic; @@ -4892,6 +5051,10 @@ struct H5C_t { hbool_t rdfsm_settled; hbool_t mdfsm_settled; + /* Fields supporting page buffer hints */ + const H5C_class_t * curr_io_type; + hbool_t curr_read_speculative; + #if H5C_COLLECT_CACHE_STATS /* stats fields */ int64_t hits[H5C__MAX_NUM_TYPE_IDS + 1]; @@ -5025,6 +5188,8 @@ H5_DLL herr_t H5C__untag_entry(H5C_t *cache, H5C_cache_entry_t *entry); /* Testing functions */ #ifdef H5C_TESTING H5_DLL herr_t H5C__verify_cork_tag_test(hid_t fid, H5O_token_t tag_token, hbool_t status); +H5_DLL void H5C_set_curr_io_type_splitable(H5C_t * cache_ptr, + hbool_t set_splitable); #endif /* H5C_TESTING */ #endif /* _H5Cpkg_H */ |