fix(drm): reap signalled render fences during commit retries

commit: d40e1f9cb4a28473bbe0142dec554b386e86de84
author: brice · 9h ago · 2026-10-22 12:05 UTC
parent: 7703bb9
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email
checks: 1/1

2 files · +76 -1

A internal/adapters/drm/nomem_reads_test.go +73 -0

@@ -0,0 +1,73 @@
	1	+	package drm
	2	+
	3	+	import (
	4	+	"context"
	5	+	"errors"
	6	+	"os"
	7	+	"testing"
	8	+	"testing/synctest"
	9	+	"time"
	10	+
	11	+	portsmocks "github.com/bnema/neferwl/internal/mocks/ports"
	12	+	"github.com/bnema/neferwl/internal/ports"
	13	+	"github.com/stretchr/testify/mock"
	14	+	"golang.org/x/sys/unix"
	15	+	)
	16	+
	17	+	// A static scene produces no reportDirty wake. Memory retries must reap
	18	+	// completed reads themselves, without dropping an older unsignalled read.
	19	+	func TestNoMemRetriesReapSignalledReads(t *testing.T) {
	20	+	synctest.Test(t, func(t *testing.T) {
	21	+	errs := make([]error, 40)
	22	+	for i := range errs {
	23	+	errs[i] = unix.ENOMEM
	24	+	}
	25	+	o, _, commits := testOutput(t, errs...)
	26	+	defer o.dropRead()
	27	+	held, signal := fencePipe(t)
	28	+	o.holdRead(held)
	29	+	pending := o.readFences[0]
	30	+	r := portsmocks.NewMockRenderer(t)
	31	+	r.EXPECT().UseTarget(0).Return()
	32	+	r.EXPECT().Render(mock.Anything, mock.Anything).RunAndReturn(func(ports.Scene, map[ports.WindowID]ports.SurfaceContent) (*os.File, error) {
	33	+	f, w := fencePipe(t)
	34	+	if _, err := w.Write([]byte{1}); err != nil {
	35	+	t.Fatal(err)
	36	+	}
	37	+	return f, nil
	38	+	}).Times(len(errs))
	39	+	enabled := true
	40	+	var previous *os.File
	41	+	for range errs {
	42	+	_, err := o.submitFrame(context.Background(), r, ports.Scene{Seq: 1}, nil, nil, nil, nil)
	43	+	if !errors.Is(err, unix.ENOMEM) \|\| !o.commitFailed(err, &enabled) {
	44	+	t.Fatalf("refusal: %v", err)
	45	+	}
	46	+	if len(o.readFences) != 2 \|\| o.readFences[0] != pending {
	47	+	t.Fatalf("retained %d fences; unsignalled read preserved=%v", len(o.readFences), len(o.readFences) > 0 && o.readFences[0] == pending)
	48	+	}
	49	+	if previous != nil {
	50	+	if _, err := previous.Stat(); !errors.Is(err, os.ErrClosed) {
	51	+	t.Fatalf("completed descriptor not closed: %v", err)
	52	+	}
	53	+	}
	54	+	previous = o.readFences[1]
	55	+	time.Sleep(o.frame.nomemBackoff)
	56	+	if o.expire() {
	57	+	t.Fatal("memory retry requested modeset")
	58	+	}
	59	+	}
	60	+	if len(*commits) != len(errs) {
	61	+	t.Fatalf("commits %d", len(*commits))
	62	+	}
	63	+	if o.readDone() \|\| len(o.readFences) != 1 \|\| o.readFences[0] != pending {
	64	+	t.Fatal("unsignalled read lost")
	65	+	}
	66	+	if _, err := signal.Write([]byte{1}); err != nil {
	67	+	t.Fatal(err)
	68	+	}
	69	+	if !o.readDone() \|\| len(o.readFences) != 0 {
	70	+	t.Fatal("completed read not reaped")
	71	+	}
	72	+	})
	73	+	}

@@ -0,0 +1,73 @@
	1	+	package drm
	2	+
	3	+	import (
	4	+	"context"
	5	+	"errors"
	6	+	"os"
	7	+	"testing"
	8	+	"testing/synctest"
	9	+	"time"
	10	+
	11	+	portsmocks "github.com/bnema/neferwl/internal/mocks/ports"
	12	+	"github.com/bnema/neferwl/internal/ports"
	13	+	"github.com/stretchr/testify/mock"
	14	+	"golang.org/x/sys/unix"
	15	+	)
	16	+
	17	+	// A static scene produces no reportDirty wake. Memory retries must reap
	18	+	// completed reads themselves, without dropping an older unsignalled read.
	19	+	func TestNoMemRetriesReapSignalledReads(t *testing.T) {
	20	+	synctest.Test(t, func(t *testing.T) {
	21	+	errs := make([]error, 40)
	22	+	for i := range errs {
	23	+	errs[i] = unix.ENOMEM
	24	+	}
	25	+	o, _, commits := testOutput(t, errs...)
	26	+	defer o.dropRead()
	27	+	held, signal := fencePipe(t)
	28	+	o.holdRead(held)
	29	+	pending := o.readFences[0]
	30	+	r := portsmocks.NewMockRenderer(t)
	31	+	r.EXPECT().UseTarget(0).Return()
	32	+	r.EXPECT().Render(mock.Anything, mock.Anything).RunAndReturn(func(ports.Scene, map[ports.WindowID]ports.SurfaceContent) (*os.File, error) {
	33	+	f, w := fencePipe(t)
	34	+	if _, err := w.Write([]byte{1}); err != nil {
	35	+	t.Fatal(err)
	36	+	}
	37	+	return f, nil
	38	+	}).Times(len(errs))
	39	+	enabled := true
	40	+	var previous *os.File
	41	+	for range errs {
	42	+	_, err := o.submitFrame(context.Background(), r, ports.Scene{Seq: 1}, nil, nil, nil, nil)
	43	+	if !errors.Is(err, unix.ENOMEM) \|\| !o.commitFailed(err, &enabled) {
	44	+	t.Fatalf("refusal: %v", err)
	45	+	}
	46	+	if len(o.readFences) != 2 \|\| o.readFences[0] != pending {
	47	+	t.Fatalf("retained %d fences; unsignalled read preserved=%v", len(o.readFences), len(o.readFences) > 0 && o.readFences[0] == pending)
	48	+	}
	49	+	if previous != nil {
	50	+	if _, err := previous.Stat(); !errors.Is(err, os.ErrClosed) {
	51	+	t.Fatalf("completed descriptor not closed: %v", err)
	52	+	}
	53	+	}
	54	+	previous = o.readFences[1]
	55	+	time.Sleep(o.frame.nomemBackoff)
	56	+	if o.expire() {
	57	+	t.Fatal("memory retry requested modeset")
	58	+	}
	59	+	}
	60	+	if len(*commits) != len(errs) {
	61	+	t.Fatalf("commits %d", len(*commits))
	62	+	}
	63	+	if o.readDone() \|\| len(o.readFences) != 1 \|\| o.readFences[0] != pending {
	64	+	t.Fatal("unsignalled read lost")
	65	+	}
	66	+	if _, err := signal.Write([]byte{1}); err != nil {
	67	+	t.Fatal(err)
	68	+	}
	69	+	if !o.readDone() \|\| len(o.readFences) != 0 {
	70	+	t.Fatal("completed read not reaped")
	71	+	}
	72	+	})
	73	+	}

M internal/adapters/drm/reads.go +3 -1


@@ -41,8 +41,10 @@ func signalled(fs []*os.File) bool {
41	41		return true
42	42		}
43	43
44		-	// holdRead keeps the fences of a frame that was not committed.
	44	+	// holdRead keeps the fences of a frame that was not committed. Reap old
	45	+	// completed reads even when no content publication asks for a report.
45	46		func (o Output) holdRead(fs ...os.File) {
	47	+	o.readDone()
46	48		o.readFences = append(o.readFences, dupFences(fs...)...)
47	49		}
48	50

 	return true
 }
-// holdRead keeps the fences of a frame that was not committed.
+// holdRead keeps the fences of a frame that was not committed. Reap old
+// completed reads even when no content publication asks for a report.
 func (o *Output) holdRead(fs ...*os.File) {
+	o.readDone()
 	o.readFences = append(o.readFences, dupFences(fs...)...)
 }