util/mesa-db: Open DB files during access time

Open DB files when DB is accessed and close them afterwards to reduce
number of FDs used by multi-part DB cache.

Fixes: fd9f7b748e2e ("util/mesa-db: Introduce multipart mesa-db cache")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/11776
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/11810
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Acked-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30988>

1 files changed, 48 insertions, 7 deletions

diff --git a/src/util/mesa_cache_db.c b/src/util/mesa_cache_db.c
index 77a89a20fa4..f7536ae4a86 100644
--- a/src/util/mesa_cache_db.c
+++ b/src/util/mesa_cache_db.c
@@ -83,6 +83,12 @@ static inline bool mesa_db_truncate(FILE *file, long pos)
    return !ftruncate(fileno(file), pos);
 }
 
+static bool
+mesa_db_reopen_file(struct mesa_cache_db_file *db_file);
+
+static void
+mesa_db_close_file(struct mesa_cache_db_file *db_file);
+
 static int
 mesa_db_flock(FILE *file, int op)
 {
@@ -100,8 +106,12 @@ mesa_db_lock(struct mesa_cache_db *db)
 {
    simple_mtx_lock(&db->flock_mtx);
 
+   if (!mesa_db_reopen_file(&db->index) ||
+       !mesa_db_reopen_file(&db->cache))
+      goto close_files;
+
    if (mesa_db_flock(db->cache.file, LOCK_EX) < 0)
-      goto unlock_mtx;
+      goto close_files;
 
    if (mesa_db_flock(db->index.file, LOCK_EX) < 0)
       goto unlock_cache;
@@ -110,7 +120,10 @@ mesa_db_lock(struct mesa_cache_db *db)
 
 unlock_cache:
    mesa_db_flock(db->cache.file, LOCK_UN);
-unlock_mtx:
+close_files:
+   mesa_db_close_file(&db->index);
+   mesa_db_close_file(&db->cache);
+
    simple_mtx_unlock(&db->flock_mtx);
 
    return false;
@@ -121,6 +134,10 @@ mesa_db_unlock(struct mesa_cache_db *db)
 {
    mesa_db_flock(db->index.file, LOCK_UN);
    mesa_db_flock(db->cache.file, LOCK_UN);
+
+   mesa_db_close_file(&db->index);
+   mesa_db_close_file(&db->cache);
+
    simple_mtx_unlock(&db->flock_mtx);
 }
 
@@ -495,10 +512,34 @@ mesa_db_open_file(struct mesa_cache_db_file *db_file,
    return true;
 }
 
+static bool
+mesa_db_reopen_file(struct mesa_cache_db_file *db_file)
+{
+   if (db_file->file)
+      return true;
+
+   db_file->file = mesa_db_fopen(db_file->path);
+   if (!db_file->file)
+      return false;
+
+   return true;
+}
+
 static void
 mesa_db_close_file(struct mesa_cache_db_file *db_file)
 {
-   fclose(db_file->file);
+   if (db_file->file) {
+      fclose(db_file->file);
+      db_file->file = NULL;
+   }
+}
+
+static void
+mesa_db_free_file(struct mesa_cache_db_file *db_file)
+{
+   if (db_file->file)
+      fclose(db_file->file);
+
    free(db_file->path);
 }
 
@@ -718,9 +759,9 @@ destroy_mtx:
 
    ralloc_free(db->mem_ctx);
 close_index:
-   mesa_db_close_file(&db->index);
+   mesa_db_free_file(&db->index);
 close_cache:
-   mesa_db_close_file(&db->cache);
+   mesa_db_free_file(&db->cache);
 
    return false;
 }
@@ -754,8 +795,8 @@ mesa_cache_db_close(struct mesa_cache_db *db)
       db->index_entries = NULL;
    }
 
-   mesa_db_close_file(&db->index);
-   mesa_db_close_file(&db->cache);
+   mesa_db_free_file(&db->index);
+   mesa_db_free_file(&db->cache);
 }
 
 void