dsm_registry.h File Reference

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Functions
void *	GetNamedDSMSegment (const char *name, size_t size, void(*init_callback)(void *ptr), bool *found)
Size	DSMRegistryShmemSize (void)
void	DSMRegistryShmemInit (void)

Function Documentation

DSMRegistryShmemInit()

void DSMRegistryShmemInit

(

void

)

Definition at line 69 of file dsm_registry.c.

{
    bool        found;
 
    DSMRegistryCtx = (DSMRegistryCtxStruct *)
        ShmemInitStruct("DSM Registry Data",
                        DSMRegistryShmemSize(),
                        &found);
 
    if (!found)
    {
        DSMRegistryCtx->dsah = DSA_HANDLE_INVALID;
        DSMRegistryCtx->dshh = DSHASH_HANDLE_INVALID;
    }
}

References DSA_HANDLE_INVALID, DSMRegistryCtxStruct::dsah, DSHASH_HANDLE_INVALID, DSMRegistryCtxStruct::dshh, DSMRegistryCtx, DSMRegistryShmemSize(), and ShmemInitStruct().

Referenced by CreateOrAttachShmemStructs().

DSMRegistryShmemSize()

Size DSMRegistryShmemSize

(

void

)

Definition at line 63 of file dsm_registry.c.

{
    return MAXALIGN(sizeof(DSMRegistryCtxStruct));
}

References MAXALIGN.

Referenced by CalculateShmemSize(), and DSMRegistryShmemInit().

GetNamedDSMSegment()

void* GetNamedDSMSegment	(	const char *	name,
		size_t	size,
		void(*)(void *ptr)	init_callback,
		bool *	found
	)

Definition at line 131 of file dsm_registry.c.

{
    DSMRegistryEntry *entry;
    MemoryContext oldcontext;
    void       *ret;
 
    Assert(found);
 
    if (!name || *name == '\0')
        ereport(ERROR,
                (errmsg("DSM segment name cannot be empty")));
 
    if (strlen(name) >= offsetof(DSMRegistryEntry, handle))
        ereport(ERROR,
                (errmsg("DSM segment name too long")));
 
    if (size == 0)
        ereport(ERROR,
                (errmsg("DSM segment size must be nonzero")));
 
    /* Be sure any local memory allocated by DSM/DSA routines is persistent. */
    oldcontext = MemoryContextSwitchTo(TopMemoryContext);
 
    /* Connect to the registry. */
    init_dsm_registry();
 
    entry = dshash_find_or_insert(dsm_registry_table, name, found);
    if (!(*found))
    {
        /* Initialize the segment. */
        dsm_segment *seg = dsm_create(size, 0);
 
        dsm_pin_segment(seg);
        dsm_pin_mapping(seg);
        entry->handle = dsm_segment_handle(seg);
        entry->size = size;
        ret = dsm_segment_address(seg);
 
        if (init_callback)
            (*init_callback) (ret);
    }
    else if (entry->size != size)
    {
        ereport(ERROR,
                (errmsg("requested DSM segment size does not match size of "
                        "existing segment")));
    }
    else
    {
        dsm_segment *seg = dsm_find_mapping(entry->handle);
 
        /* If the existing segment is not already attached, attach it now. */
        if (seg == NULL)
        {
            seg = dsm_attach(entry->handle);
            if (seg == NULL)
                elog(ERROR, "could not map dynamic shared memory segment");
 
            dsm_pin_mapping(seg);
        }
 
        ret = dsm_segment_address(seg);
    }
 
    dshash_release_lock(dsm_registry_table, entry);
    MemoryContextSwitchTo(oldcontext);
 
    return ret;
}

References Assert, dshash_find_or_insert(), dshash_release_lock(), dsm_attach(), dsm_create(), dsm_find_mapping(), dsm_pin_mapping(), dsm_pin_segment(), dsm_registry_table, dsm_segment_address(), dsm_segment_handle(), elog, ereport, errmsg(), ERROR, DSMRegistryEntry::handle, init_dsm_registry(), MemoryContextSwitchTo(), name, DSMRegistryEntry::size, size, and TopMemoryContext.

Referenced by apw_init_shmem(), injection_init_shmem(), and tdr_attach_shmem().