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glocalfileinfo: Use a single timeout source at a time for hidden file cache

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As hidden file caches currently work, every look up on a directory caches
its .hidden file contents, and sets a 5s timeout to prune the directory
from the cache.

This creates a problem for usecases like Tracker Miners, which is in the
business of inspecting as many files as possible from as many directories
as possible in the shortest time possible. One timeout is created for each
directory, which possibly means gobbling thousands of entries in the hidden
file cache. This adds as many GSources to the glib worker thread, with the
involved CPU overhead in iterating those in its main context.

To fix this, use a unique timeout that will keep running until the cache
is empty. This will keep the overhead constant with many files/folders
being queried.
This commit is contained in:
Carlos Garnacho 2020-11-01 20:55:27 +01:00 committed by Philip Withnall
parent 4daaf303a0
commit 92c19ebda2
1 changed files with 61 additions and 18 deletions
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79
gio/glocalfileinfo.c
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@ -1547,15 +1547,45 @@ win32_get_file_user_info (const gchar *filename,
/* support for '.hidden' files */
G_LOCK_DEFINE_STATIC (hidden_cache);
static GHashTable *hidden_cache;
static GSource *hidden_cache_source = NULL; /* Under the hidden_cache lock */
static guint hidden_cache_ttl_secs = 5;
static guint hidden_cache_ttl_jitter_secs = 2;
typedef struct
{
GHashTable *hidden_files;
gint64 timestamp_secs;
} HiddenCacheData;
static gboolean
remove_from_hidden_cache (gpointer user_data)
{
HiddenCacheData *data;
GHashTableIter iter;
gboolean retval;
gint64 timestamp_secs;
G_LOCK (hidden_cache);
g_hash_table_remove (hidden_cache, user_data);
timestamp_secs = g_source_get_time (hidden_cache_source) / G_USEC_PER_SEC;
g_hash_table_iter_init (&iter, hidden_cache);
while (g_hash_table_iter_next (&iter, NULL, (gpointer *) &data))
{
if (timestamp_secs > data->timestamp_secs + hidden_cache_ttl_secs)
g_hash_table_iter_remove (&iter);
}
if (g_hash_table_size (hidden_cache) == 0)
{
g_clear_pointer (&hidden_cache_source, g_source_unref);
retval = G_SOURCE_REMOVE;
}
else
retval = G_SOURCE_CONTINUE;
G_UNLOCK (hidden_cache);
return FALSE;
return retval;
}
static GHashTable *
@ -1593,16 +1623,19 @@ read_hidden_file (const gchar *dirname)
}
static void
maybe_unref_hash_table (gpointer data)
free_hidden_file_data (gpointer user_data)
{
if (data != NULL)
g_hash_table_unref (data);
HiddenCacheData *data = user_data;
g_clear_pointer (&data->hidden_files, g_hash_table_unref);
g_free (data);
}
static gboolean
file_is_hidden (const gchar *path,
const gchar *basename)
{
HiddenCacheData *data;
gboolean result;
gchar *dirname;
gpointer table;
@ -1613,28 +1646,38 @@ file_is_hidden (const gchar *path,
if G_UNLIKELY (hidden_cache == NULL)
hidden_cache = g_hash_table_new_full (g_str_hash, g_str_equal,
g_free, maybe_unref_hash_table);
g_free, free_hidden_file_data);
if (!g_hash_table_lookup_extended (hidden_cache, dirname,
NULL, &table))
NULL, (gpointer *) &data))
{
gchar *mydirname;
GSource *remove_from_cache_source;
data = g_new0 (HiddenCacheData, 1);
data->hidden_files = table = read_hidden_file (dirname);
data->timestamp_secs = g_get_monotonic_time () / G_USEC_PER_SEC;
g_hash_table_insert (hidden_cache,
mydirname = g_strdup (dirname),
table = read_hidden_file (dirname));
data);
remove_from_cache_source = g_timeout_source_new_seconds (5);
g_source_set_priority (remove_from_cache_source, G_PRIORITY_DEFAULT);
g_source_set_callback (remove_from_cache_source,
remove_from_hidden_cache,
mydirname,
NULL);
g_source_attach (remove_from_cache_source,
GLIB_PRIVATE_CALL (g_get_worker_context) ());
g_source_unref (remove_from_cache_source);
if (!hidden_cache_source)
{
hidden_cache_source =
g_timeout_source_new_seconds (hidden_cache_ttl_secs +
hidden_cache_ttl_jitter_secs);
g_source_set_priority (hidden_cache_source, G_PRIORITY_DEFAULT);
g_source_set_name (hidden_cache_source,
"[gio] remove_from_hidden_cache");
g_source_set_callback (hidden_cache_source,
remove_from_hidden_cache,
NULL, NULL);
g_source_attach (hidden_cache_source,
GLIB_PRIVATE_CALL (g_get_worker_context) ());
}
}
else
table = data->hidden_files;
result = table != NULL && g_hash_table_contains (table, basename);