/* caching.c : in-memory caching
*
* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
* ====================================================================
*/
#include "fs.h"
#include "fs_fs.h"
#include "id.h"
#include "dag.h"
#include "temp_serializer.h"
#include "../libsvn_fs/fs-loader.h"
#include "svn_config.h"
#include "svn_cache_config.h"
#include "svn_private_config.h"
#include "svn_hash.h"
#include "private/svn_debug.h"
/* Return a memcache in *MEMCACHE_P for FS if it's configured to use
memcached, or NULL otherwise. Also, sets *FAIL_STOP to a boolean
indicating whether cache errors should be returned to the caller or
just passed to the FS warning handler. Use FS->pool for allocating
the memcache, and POOL for temporary allocations. */
static svn_error_t *
read_config(svn_memcache_t **memcache_p,
svn_boolean_t *fail_stop,
svn_boolean_t *cache_txdeltas,
svn_boolean_t *cache_fulltexts,
svn_fs_t *fs,
apr_pool_t *pool)
{
fs_fs_data_t *ffd = fs->fsap_data;
SVN_ERR(svn_cache__make_memcache_from_config(memcache_p, ffd->config,
fs->pool));
/* don't cache text deltas by default.
* Once we reconstructed the fulltexts from the deltas,
* these deltas are rarely re-used. Therefore, only tools
* like svnadmin will activate this to speed up operations
* dump and verify.
*/
*cache_txdeltas
= svn_hash__get_bool(fs->config,
SVN_FS_CONFIG_FSFS_CACHE_DELTAS,
FALSE);
/* by default, cache fulltexts.
* Most SVN tools care about reconstructed file content.
* Thus, this is a reasonable default.
* SVN admin tools may set that to FALSE because fulltexts
* won't be re-used rendering the cache less effective
* by squeezing wanted data out.
*/
*cache_fulltexts
= svn_hash__get_bool(fs->config,
SVN_FS_CONFIG_FSFS_CACHE_FULLTEXTS,
TRUE);
return svn_config_get_bool(ffd->config, fail_stop,
CONFIG_SECTION_CACHES, CONFIG_OPTION_FAIL_STOP,
FALSE);
}
/* Implements svn_cache__error_handler_t */
static svn_error_t *
warn_on_cache_errors(svn_error_t *err,
void *baton,
apr_pool_t *pool)
{
svn_fs_t *fs = baton;
(fs->warning)(fs->warning_baton, err);
svn_error_clear(err);
return SVN_NO_ERROR;
}
#ifdef SVN_DEBUG_CACHE_DUMP_STATS
/* Baton to be used for the dump_cache_statistics() pool cleanup function, */
struct dump_cache_baton_t
{
/* the pool about to be cleaned up. Will be used for temp. allocations. */
apr_pool_t *pool;
/* the cache to dump the statistics for */
svn_cache__t *cache;
};
/* APR pool cleanup handler that will printf the statistics of the
cache referenced by the baton in BATON_VOID. */
static apr_status_t
dump_cache_statistics(void *baton_void)
{
struct dump_cache_baton_t *baton = baton_void;
apr_status_t result = APR_SUCCESS;
svn_cache__info_t info;
svn_string_t *text_stats;
apr_array_header_t *lines;
int i;
svn_error_t *err = svn_cache__get_info(baton->cache,
&info,
TRUE,
baton->pool);
if (! err)
{
text_stats = svn_cache__format_info(&info, baton->pool);
lines = svn_cstring_split(text_stats->data, "\n", FALSE, baton->pool);
for (i = 0; i < lines->nelts; ++i)
{
const char *line = APR_ARRAY_IDX(lines, i, const char *);
#ifdef SVN_DEBUG
SVN_DBG(("%s\n", line));
#endif
}
}
/* process error returns */
if (err)
{
result = err->apr_err;
svn_error_clear(err);
}
return result;
}
#endif /* SVN_DEBUG_CACHE_DUMP_STATS */
/* This function sets / registers the required callbacks for a given
* not transaction-specific CACHE object in FS, if CACHE is not NULL.
*
* All these svn_cache__t instances shall be handled uniformly. Unless
* NO_HANDLER is true, register an error handler that reports errors
* as warnings for the given CACHE.
*/
static svn_error_t *
init_callbacks(svn_cache__t *cache,
svn_fs_t *fs,
svn_boolean_t no_handler,
apr_pool_t *pool)
{
if (cache != NULL)
{
#ifdef SVN_DEBUG_CACHE_DUMP_STATS
/* schedule printing the access statistics upon pool cleanup,
* i.e. end of FSFS session.
*/
struct dump_cache_baton_t *baton;
baton = apr_palloc(pool, sizeof(*baton));
baton->pool = pool;
baton->cache = cache;
apr_pool_cleanup_register(pool,
baton,
dump_cache_statistics,
apr_pool_cleanup_null);
#endif
if (! no_handler)
SVN_ERR(svn_cache__set_error_handler(cache,
warn_on_cache_errors,
fs,
pool));
}
return SVN_NO_ERROR;
}
/* Sets *CACHE_P to cache instance based on provided options.
* Creates memcache if MEMCACHE is not NULL. Creates membuffer cache if
* MEMBUFFER is not NULL. Fallbacks to inprocess cache if MEMCACHE and
* MEMBUFFER are NULL and pages is non-zero. Sets *CACHE_P to NULL
* otherwise.
*
* Cache is allocated in POOL.
* */
static svn_error_t *
create_cache(svn_cache__t **cache_p,
svn_memcache_t *memcache,
svn_membuffer_t *membuffer,
apr_int64_t pages,
apr_int64_t items_per_page,
svn_cache__serialize_func_t serializer,
svn_cache__deserialize_func_t deserializer,
apr_ssize_t klen,
const char *prefix,
apr_pool_t *pool)
{
if (memcache)
{
SVN_ERR(svn_cache__create_memcache(cache_p, memcache,
serializer, deserializer, klen,
prefix, pool));
}
else if (membuffer)
{
SVN_ERR(svn_cache__create_membuffer_cache(
cache_p, membuffer, serializer, deserializer,
klen, prefix, pool));
}
else if (pages)
{
SVN_ERR(svn_cache__create_inprocess(
cache_p, serializer, deserializer, klen, pages,
items_per_page, FALSE, prefix, pool));
}
else
{
*cache_p = NULL;
}
return SVN_NO_ERROR;
}
svn_error_t *
svn_fs_fs__initialize_caches(svn_fs_t *fs,
apr_pool_t *pool)
{
fs_fs_data_t *ffd = fs->fsap_data;
const char *prefix = apr_pstrcat(pool,
"fsfs:", ffd->uuid,
"/", fs->path, ":",
(char *)NULL);
svn_memcache_t *memcache;
svn_membuffer_t *membuffer;
svn_boolean_t no_handler;
svn_boolean_t cache_txdeltas;
svn_boolean_t cache_fulltexts;
/* Evaluating the cache configuration. */
SVN_ERR(read_config(&memcache,
&no_handler,
&cache_txdeltas,
&cache_fulltexts,
fs,
pool));
membuffer = svn_cache__get_global_membuffer_cache();
/* Make the cache for revision roots. For the vast majority of
* commands, this is only going to contain a few entries (svnadmin
* dump/verify is an exception here), so to reduce overhead let's
* try to keep it to just one page. I estimate each entry has about
* 72 bytes of overhead (svn_revnum_t key, svn_fs_id_t +
* id_private_t + 3 strings for value, and the cache_entry); the
* default pool size is 8192, so about a hundred should fit
* comfortably. */
SVN_ERR(create_cache(&(ffd->rev_root_id_cache),
NULL,
membuffer,
1, 100,
svn_fs_fs__serialize_id,
svn_fs_fs__deserialize_id,
sizeof(svn_revnum_t),
apr_pstrcat(pool, prefix, "RRI", (char *)NULL),
fs->pool));
SVN_ERR(init_callbacks(ffd->rev_root_id_cache, fs, no_handler, pool));
/* Rough estimate: revision DAG nodes have size around 320 bytes, so
* let's put 16 on a page. */
SVN_ERR(create_cache(&(ffd->rev_node_cache),
NULL,
membuffer,
1024, 16,
svn_fs_fs__dag_serialize,
svn_fs_fs__dag_deserialize,
APR_HASH_KEY_STRING,
apr_pstrcat(pool, prefix, "DAG", NULL),
fs->pool));
SVN_ERR(init_callbacks(ffd->rev_node_cache, fs, no_handler, pool));
/* Very rough estimate: 1K per directory. */
SVN_ERR(create_cache(&(ffd->dir_cache),
NULL,
membuffer,
1024, 8,
svn_fs_fs__serialize_dir_entries,
svn_fs_fs__deserialize_dir_entries,
APR_HASH_KEY_STRING,
apr_pstrcat(pool, prefix, "DIR", (char *)NULL),
fs->pool));
SVN_ERR(init_callbacks(ffd->dir_cache, fs, no_handler, pool));
/* Only 16 bytes per entry (a revision number + the corresponding offset).
Since we want ~8k pages, that means 512 entries per page. */
SVN_ERR(create_cache(&(ffd->packed_offset_cache),
NULL,
membuffer,
32, 1,
svn_fs_fs__serialize_manifest,
svn_fs_fs__deserialize_manifest,
sizeof(svn_revnum_t),
apr_pstrcat(pool, prefix, "PACK-MANIFEST",
(char *)NULL),
fs->pool));
SVN_ERR(init_callbacks(ffd->packed_offset_cache, fs, no_handler, pool));
/* initialize fulltext cache as configured */
ffd->fulltext_cache = NULL;
if (cache_fulltexts)
{
SVN_ERR(create_cache(&(ffd->fulltext_cache),
memcache,
membuffer,
0, 0, /* Do not use inprocess cache */
/* Values are svn_string_t */
NULL, NULL,
APR_HASH_KEY_STRING,
apr_pstrcat(pool, prefix, "TEXT", (char *)NULL),
fs->pool));
}
SVN_ERR(init_callbacks(ffd->fulltext_cache, fs, no_handler, pool));
/* initialize txdelta window cache, if that has been enabled */
if (cache_txdeltas)
{
SVN_ERR(create_cache(&(ffd->txdelta_window_cache),
NULL,
membuffer,
0, 0, /* Do not use inprocess cache */
svn_fs_fs__serialize_txdelta_window,
svn_fs_fs__deserialize_txdelta_window,
APR_HASH_KEY_STRING,
apr_pstrcat(pool, prefix, "TXDELTA_WINDOW",
(char *)NULL),
fs->pool));
}
else
{
ffd->txdelta_window_cache = NULL;
}
SVN_ERR(init_callbacks(ffd->txdelta_window_cache, fs, no_handler, pool));
/* initialize node revision cache, if caching has been enabled */
SVN_ERR(create_cache(&(ffd->node_revision_cache),
NULL,
membuffer,
0, 0, /* Do not use inprocess cache */
svn_fs_fs__serialize_node_revision,
svn_fs_fs__deserialize_node_revision,
APR_HASH_KEY_STRING,
apr_pstrcat(pool, prefix, "NODEREVS", (char *)NULL),
fs->pool));
SVN_ERR(init_callbacks(ffd->node_revision_cache, fs, no_handler, pool));
return SVN_NO_ERROR;
}
/* Baton to be used for the remove_txn_cache() pool cleanup function, */
struct txn_cleanup_baton_t
{
/* the cache to reset */
svn_cache__t *txn_cache;
/* the position where to reset it */
svn_cache__t **to_reset;
};
/* APR pool cleanup handler that will reset the cache pointer given in
BATON_VOID. */
static apr_status_t
remove_txn_cache(void *baton_void)
{
struct txn_cleanup_baton_t *baton = baton_void;
/* be careful not to hurt performance by resetting newer txn's caches. */
if (*baton->to_reset == baton->txn_cache)
{
/* This is equivalent to calling svn_fs_fs__reset_txn_caches(). */
*baton->to_reset = NULL;
}
return APR_SUCCESS;
}
/* This function sets / registers the required callbacks for a given
* transaction-specific *CACHE object, if CACHE is not NULL and a no-op
* otherwise. In particular, it will ensure that *CACHE gets reset to NULL
* upon POOL destruction latest.
*/
static void
init_txn_callbacks(svn_cache__t **cache,
apr_pool_t *pool)
{
if (*cache != NULL)
{
struct txn_cleanup_baton_t *baton;
baton = apr_palloc(pool, sizeof(*baton));
baton->txn_cache = *cache;
baton->to_reset = cache;
apr_pool_cleanup_register(pool,
baton,
remove_txn_cache,
apr_pool_cleanup_null);
}
}
svn_error_t *
svn_fs_fs__initialize_txn_caches(svn_fs_t *fs,
const char *txn_id,
apr_pool_t *pool)
{
fs_fs_data_t *ffd = fs->fsap_data;
/* Transaction content needs to be carefully prefixed to virtually
eliminate any chance for conflicts. The (repo, txn_id) pair
should be unique but if a transaction fails, it might be possible
to start a new transaction later that receives the same id.
Therefore, throw in a uuid as well - just to be sure. */
const char *prefix = apr_pstrcat(pool,
"fsfs:", ffd->uuid,
"/", fs->path,
":", txn_id,
":", svn_uuid_generate(pool), ":",
(char *)NULL);
/* We don't support caching for concurrent transactions in the SAME
* FSFS session. Maybe, you forgot to clean POOL. */
if (ffd->txn_dir_cache != NULL || ffd->concurrent_transactions)
{
ffd->txn_dir_cache = NULL;
ffd->concurrent_transactions = TRUE;
return SVN_NO_ERROR;
}
/* create a txn-local directory cache */
if (svn_cache__get_global_membuffer_cache())
SVN_ERR(svn_cache__create_membuffer_cache(&(ffd->txn_dir_cache),
svn_cache__get_global_membuffer_cache(),
svn_fs_fs__serialize_dir_entries,
svn_fs_fs__deserialize_dir_entries,
APR_HASH_KEY_STRING,
apr_pstrcat(pool, prefix, "TXNDIR",
(char *)NULL),
pool));
else
SVN_ERR(svn_cache__create_inprocess(&(ffd->txn_dir_cache),
svn_fs_fs__serialize_dir_entries,
svn_fs_fs__deserialize_dir_entries,
APR_HASH_KEY_STRING,
1024, 8, FALSE,
apr_pstrcat(pool, prefix, "TXNDIR",
(char *)NULL),
pool));
/* reset the transaction-specific cache if the pool gets cleaned up. */
init_txn_callbacks(&(ffd->txn_dir_cache), pool);
return SVN_NO_ERROR;
}
void
svn_fs_fs__reset_txn_caches(svn_fs_t *fs)
{
/* we can always just reset the caches. This may degrade performance but
* can never cause in incorrect behavior. */
fs_fs_data_t *ffd = fs->fsap_data;
ffd->txn_dir_cache = NULL;
}