pipe_cache_policy.h File Reference

Whether one pipeline node must keep a host-RAM copy of its output. More...

#include <glib.h>
#include "system/macros.h"

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Data Structures
struct	dt_dev_pipe_cache_policy_inputs_t
	Everything the decision depends on, named. More...

Typedefs
typedef struct dt_dev_pipe_cache_policy_inputs_t	dt_dev_pipe_cache_policy_inputs_t
	Everything the decision depends on, named.

Functions
static gboolean	dt_dev_pipe_cache_policy_decide (const dt_dev_pipe_cache_policy_inputs_t *in, const gboolean inherited_requirement, gboolean *upstream_requirement)
	Decide one node's host-cache requirement, walking the pipe from the end backwards.

Detailed Description

Whether one pipeline node must keep a host-RAM copy of its output.

Split out of _seal_opencl_cache_policy() so the decision is a pure function of named inputs. That is not tidiness: the outcome it computes – per-piece cache_output_on_ram – is invisible to every check this project runs. It changes no pixel in an export (the export path drives the pipe directly and never reaches the seal), it changes no hash, and it produces no log unless someone is already looking. The one time it was wrong, the symptom was a downstream module silently reading stale host bytes from a rekeyed cacheline, and it was found by dumping OpenCL buffers, not by a test.

A pure function can be pinned by one, which is what src/tests/unittests/test_pipe_cache_policy.c does. Gathering the inputs – which of them come from the GUI, which from the pipe – stays in dev_pixelpipe.c, where it can see those things.

Definition in file pipe_cache_policy.h.

Typedef Documentation

dt_dev_pipe_cache_policy_inputs_t

typedef struct dt_dev_pipe_cache_policy_inputs_t dt_dev_pipe_cache_policy_inputs_t

Everything the decision depends on, named.

Function Documentation

dt_dev_pipe_cache_policy_decide()

static gboolean dt_dev_pipe_cache_policy_decide ( const dt_dev_pipe_cache_policy_inputs_t *  in, const gboolean  inherited_requirement, gboolean *  upstream_requirement  )

inlinestatic

Decide one node's host-cache requirement, walking the pipe from the end backwards.

Parameters

	in	The node's own inputs.
	inherited_requirement	What the nodes downstream of this one already established.
[out]	upstream_requirement	What to hand the node before this one. Never smaller than inherited_requirement – see the note below, it is the whole reason this is a function and not an expression.

Returns

TRUE when this node must keep its output in host RAM.

Definition at line 78 of file pipe_cache_policy.h.

References IS_NULL_PTR, L, and dt_dev_pipe_cache_policy_inputs_t::supports_opencl.

Referenced by _cpu_only_node_needs_its_input_on_host(), _each_own_input_reason_raises_upstream(), _each_own_output_reason_raises_own(), _gpu_node_propagates_an_inherited_requirement(), _gpu_node_requires_nothing_on_its_own(), _null_upstream_pointer_is_allowed(), and _seal_opencl_cache_policy().