Summary:

Follow-up to D106717093. The cache_loaded_ flag was used as the gate
in initialize_for_runtime to decide between the CACHE_LOADED
fast-path (reopen fd only) and the load-or-fresh-write slow path.
But it was only set true by load_packed_cache(), not by the
fresh-write path. After a fresh-write + save_packed_index closed
the fd, the next init found cache_loaded_=false → re-entered
load_packed_cache → push a second whole-file mmap region on top
of the per-entry regions from reserve_space. Same file mapped
twice; redundant VM and bookkeeping.

Replace the flag with !name_to_packed_data_metadata_.empty() as
the gate. Metadata is non-empty after BOTH paths (load and
fresh-write), so the gate is correct for both. Removes 1 field,
3 writes, and the latent double-mmap on the fresh-write-then-save
path. The from_load entry comment is updated to drop the
now-stale reference to cache_loaded_ auto-invalidation.

Differential Revision: D108178967

Summary:

Follow-up to D106717093. The cache_loaded_ flag was used as the gate
in initialize_for_runtime to decide between the CACHE_LOADED
fast-path (reopen fd only) and the load-or-fresh-write slow path.
But it was only set true by load_packed_cache(), not by the
fresh-write path. After a fresh-write + save_packed_index closed
the fd, the next init found cache_loaded_=false → re-entered
load_packed_cache → push a second whole-file mmap region on top
of the per-entry regions from reserve_space. Same file mapped
twice; redundant VM and bookkeeping.

Replace the flag with !name_to_packed_data_metadata_.empty() as
the gate. Metadata is non-empty after BOTH paths (load and
fresh-write), so the gate is correct for both. Removes 1 field,
3 writes, and the latent double-mmap on the fresh-write-then-save
path. The from_load entry comment is updated to drop the
now-stale reference to cache_loaded_ auto-invalidation.

Differential Revision: D108178967

Summary:

Follow-up to D106717093. The cache_loaded_ flag was used as the gate
in initialize_for_runtime to decide between the CACHE_LOADED
fast-path (reopen fd only) and the load-or-fresh-write slow path.
But it was only set true by load_packed_cache(), not by the
fresh-write path. After a fresh-write + save_packed_index closed
the fd, the next init found cache_loaded_=false → re-entered
load_packed_cache → push a second whole-file mmap region on top
of the per-entry regions from reserve_space. Same file mapped
twice; redundant VM and bookkeeping.

Replace the flag with !name_to_packed_data_metadata_.empty() as
the gate. Metadata is non-empty after BOTH paths (load and
fresh-write), so the gate is correct for both. Removes 1 field,
3 writes, and the latent double-mmap on the fresh-write-then-save
path. The from_load entry comment is updated to drop the
now-stale reference to cache_loaded_ auto-invalidation.

Differential Revision: D108178967

Summary:

Follow-up to D106717093. The cache_loaded_ flag was used as the gate
in initialize_for_runtime to decide between the CACHE_LOADED
fast-path (reopen fd only) and the load-or-fresh-write slow path.
But it was only set true by load_packed_cache(), not by the
fresh-write path. After a fresh-write + save_packed_index closed
the fd, the next init found cache_loaded_=false → re-entered
load_packed_cache → push a second whole-file mmap region on top
of the per-entry regions from reserve_space. Same file mapped
twice; redundant VM and bookkeeping.

Replace the flag with !name_to_packed_data_metadata_.empty() as
the gate. Metadata is non-empty after BOTH paths (load and
fresh-write), so the gate is correct for both. Removes 1 field,
3 writes, and the latent double-mmap on the fresh-write-then-save
path. The from_load entry comment is updated to drop the
now-stale reference to cache_loaded_ auto-invalidation.

Differential Revision: D108178967

Summary:

Follow-up to D106717093. The cache_loaded_ flag was used as the gate
in initialize_for_runtime to decide between the CACHE_LOADED
fast-path (reopen fd only) and the load-or-fresh-write slow path.
But it was only set true by load_packed_cache(), not by the
fresh-write path. After a fresh-write + save_packed_index closed
the fd, the next init found cache_loaded_=false → re-entered
load_packed_cache → push a second whole-file mmap region on top
of the per-entry regions from reserve_space. Same file mapped
twice; redundant VM and bookkeeping.

Replace the flag with !name_to_packed_data_metadata_.empty() as
the gate. Metadata is non-empty after BOTH paths (load and
fresh-write), so the gate is correct for both. Removes 1 field,
3 writes, and the latent double-mmap on the fresh-write-then-save
path. The from_load entry comment is updated to drop the
now-stale reference to cache_loaded_ auto-invalidation.

Reviewed By: GregoryComer

Differential Revision: D108178967

Summary:

Follow-up to D106717093. The cache_loaded_ flag was used as the gate
in initialize_for_runtime to decide between the CACHE_LOADED
fast-path (reopen fd only) and the load-or-fresh-write slow path.
But it was only set true by load_packed_cache(), not by the
fresh-write path. After a fresh-write + save_packed_index closed
the fd, the next init found cache_loaded_=false → re-entered
load_packed_cache → push a second whole-file mmap region on top
of the per-entry regions from reserve_space. Same file mapped
twice; redundant VM and bookkeeping.

Replace the flag with !name_to_packed_data_metadata_.empty() as
the gate. Metadata is non-empty after BOTH paths (load and
fresh-write), so the gate is correct for both. Removes 1 field,
3 writes, and the latent double-mmap on the fresh-write-then-save
path. The from_load entry comment is updated to drop the
now-stale reference to cache_loaded_ auto-invalidation.

Reviewed By: GregoryComer

Differential Revision: D108178967