[neovim] 05/11: tui: "backpressure": Drop messages to avoid flooding.
James McCoy
jamessan at debian.org
Sat Dec 24 21:14:14 UTC 2016
This is an automated email from the git hooks/post-receive script.
jamessan pushed a commit to branch debian/sid
in repository neovim.
commit 21940ca543c5fcaf68cb99b99b3a262d33a8204f
Author: Justin M. Keyes <justinkz at gmail.com>
Date: Mon Oct 3 10:46:11 2016 +0200
tui: "backpressure": Drop messages to avoid flooding.
Closes #1234
multiqueue:
- Implement multiqueue_size()
- Rename MultiQueueItem.parent to MultiQueueItem.parent_item, to avoid confusion
with MultiQueue.parent.
---
src/nvim/event/loop.c | 16 +++++++
src/nvim/event/multiqueue.c | 51 ++++++++++++++++-------
src/nvim/lib/queue.h | 18 ++++----
src/nvim/macros.h | 3 ++
src/nvim/tui/input.c | 2 -
src/nvim/tui/tui.c | 15 +++++++
src/nvim/ui.c | 7 ++--
src/nvim/ui_bridge.c | 33 ++++++++++++---
src/nvim/ui_bridge.h | 2 +-
src/nvim/version.c | 4 +-
test/unit/{queue_spec.lua => multiqueue_spec.lua} | 21 ++++++++++
11 files changed, 130 insertions(+), 42 deletions(-)
diff --git a/src/nvim/event/loop.c b/src/nvim/event/loop.c
index d562ac1..0e1775d 100644
--- a/src/nvim/event/loop.c
+++ b/src/nvim/event/loop.c
@@ -92,6 +92,22 @@ void loop_close(Loop *loop, bool wait)
kl_destroy(WatcherPtr, loop->children);
}
+void loop_purge(Loop *loop)
+{
+ uv_mutex_lock(&loop->mutex);
+ multiqueue_purge_events(loop->thread_events);
+ multiqueue_purge_events(loop->fast_events);
+ uv_mutex_unlock(&loop->mutex);
+}
+
+size_t loop_size(Loop *loop)
+{
+ uv_mutex_lock(&loop->mutex);
+ size_t rv = multiqueue_size(loop->thread_events);
+ uv_mutex_unlock(&loop->mutex);
+ return rv;
+}
+
static void async_cb(uv_async_t *handle)
{
Loop *l = handle->loop->data;
diff --git a/src/nvim/event/multiqueue.c b/src/nvim/event/multiqueue.c
index 7efdfc4..79b4dd9 100644
--- a/src/nvim/event/multiqueue.c
+++ b/src/nvim/event/multiqueue.c
@@ -1,6 +1,7 @@
-// Multi-level queue for selective async event processing. Multiqueue supports
-// a parent-child relationship with the following properties:
+// Multi-level queue for selective async event processing.
+// Not threadsafe; access must be synchronized externally.
//
+// Multiqueue supports a parent-child relationship with these properties:
// - pushing a node to a child queue will push a corresponding link node to the
// parent queue
// - removing a link node from a parent queue will remove the next node
@@ -14,8 +15,7 @@
// +----------------+
// | Main loop |
// +----------------+
-// ^
-// |
+//
// +----------------+
// +-------------->| Event loop |<------------+
// | +--+-------------+ |
@@ -60,7 +60,7 @@ struct multiqueue_item {
MultiQueue *queue;
struct {
Event event;
- MultiQueueItem *parent;
+ MultiQueueItem *parent_item;
} item;
} data;
bool link; // true: current item is just a link to a node in a child queue
@@ -69,9 +69,10 @@ struct multiqueue_item {
struct multiqueue {
MultiQueue *parent;
- QUEUE headtail;
+ QUEUE headtail; // circularly-linked
put_callback put_cb;
void *data;
+ size_t size;
};
#ifdef INCLUDE_GENERATED_DECLARATIONS
@@ -88,7 +89,8 @@ MultiQueue *multiqueue_new_parent(put_callback put_cb, void *data)
MultiQueue *multiqueue_new_child(MultiQueue *parent)
FUNC_ATTR_NONNULL_ALL
{
- assert(!parent->parent);
+ assert(!parent->parent); // parent cannot have a parent, more like a "root"
+ parent->size++;
return multiqueue_new(parent, NULL, NULL);
}
@@ -97,6 +99,7 @@ static MultiQueue *multiqueue_new(MultiQueue *parent, put_callback put_cb,
{
MultiQueue *rv = xmalloc(sizeof(MultiQueue));
QUEUE_INIT(&rv->headtail);
+ rv->size = 0;
rv->parent = parent;
rv->put_cb = put_cb;
rv->data = data;
@@ -110,8 +113,8 @@ void multiqueue_free(MultiQueue *this)
QUEUE *q = QUEUE_HEAD(&this->headtail);
MultiQueueItem *item = multiqueue_node_data(q);
if (this->parent) {
- QUEUE_REMOVE(&item->data.item.parent->node);
- xfree(item->data.item.parent);
+ QUEUE_REMOVE(&item->data.item.parent_item->node);
+ xfree(item->data.item.parent_item);
}
QUEUE_REMOVE(q);
xfree(item);
@@ -145,6 +148,15 @@ void multiqueue_process_events(MultiQueue *this)
}
}
+/// Removes all events without processing them.
+void multiqueue_purge_events(MultiQueue *this)
+{
+ assert(this);
+ while (!multiqueue_empty(this)) {
+ (void)multiqueue_remove(this);
+ }
+}
+
bool multiqueue_empty(MultiQueue *this)
{
assert(this);
@@ -157,6 +169,12 @@ void multiqueue_replace_parent(MultiQueue *this, MultiQueue *new_parent)
this->parent = new_parent;
}
+/// Gets the count of all events currently in the queue.
+size_t multiqueue_size(MultiQueue *this)
+{
+ return this->size;
+}
+
static Event multiqueue_remove(MultiQueue *this)
{
assert(!multiqueue_empty(this));
@@ -178,12 +196,13 @@ static Event multiqueue_remove(MultiQueue *this)
} else {
if (this->parent) {
// remove the corresponding link node in the parent queue
- QUEUE_REMOVE(&item->data.item.parent->node);
- xfree(item->data.item.parent);
+ QUEUE_REMOVE(&item->data.item.parent_item->node);
+ xfree(item->data.item.parent_item);
}
rv = item->data.item.event;
}
+ this->size--;
xfree(item);
return rv;
}
@@ -196,11 +215,13 @@ static void multiqueue_push(MultiQueue *this, Event event)
QUEUE_INSERT_TAIL(&this->headtail, &item->node);
if (this->parent) {
// push link node to the parent queue
- item->data.item.parent = xmalloc(sizeof(MultiQueueItem));
- item->data.item.parent->link = true;
- item->data.item.parent->data.queue = this;
- QUEUE_INSERT_TAIL(&this->parent->headtail, &item->data.item.parent->node);
+ item->data.item.parent_item = xmalloc(sizeof(MultiQueueItem));
+ item->data.item.parent_item->link = true;
+ item->data.item.parent_item->data.queue = this;
+ QUEUE_INSERT_TAIL(&this->parent->headtail,
+ &item->data.item.parent_item->node);
}
+ this->size++;
}
static MultiQueueItem *multiqueue_node_data(QUEUE *q)
diff --git a/src/nvim/lib/queue.h b/src/nvim/lib/queue.h
index 9fcedf2..ab92700 100644
--- a/src/nvim/lib/queue.h
+++ b/src/nvim/lib/queue.h
@@ -1,3 +1,8 @@
+// Queue implemented by circularly-linked list.
+//
+// Adapted from libuv. Simpler and more efficient than klist.h for implementing
+// queues that support arbitrary insertion/removal.
+//
// Copyright (c) 2013, Ben Noordhuis <info at bnoordhuis.nl>
//
// Permission to use, copy, modify, and/or distribute this software for any
@@ -28,6 +33,8 @@ typedef struct _queue {
#define QUEUE_DATA(ptr, type, field) \
((type *)((char *)(ptr) - offsetof(type, field)))
+// Important note: mutating the list while QUEUE_FOREACH is
+// iterating over its elements results in undefined behavior.
#define QUEUE_FOREACH(q, h) \
for ( /* NOLINT(readability/braces) */ \
(q) = (h)->next; (q) != (h); (q) = (q)->next)
@@ -56,17 +63,6 @@ static inline void QUEUE_ADD(QUEUE *const h, QUEUE *const n)
h->prev->next = h;
}
-static inline void QUEUE_SPLIT(QUEUE *const h, QUEUE *const q, QUEUE *const n)
- FUNC_ATTR_ALWAYS_INLINE
-{
- n->prev = h->prev;
- n->prev->next = n;
- n->next = q;
- h->prev = q->prev;
- h->prev->next = h;
- q->prev = n;
-}
-
static inline void QUEUE_INSERT_HEAD(QUEUE *const h, QUEUE *const q)
FUNC_ATTR_ALWAYS_INLINE
{
diff --git a/src/nvim/macros.h b/src/nvim/macros.h
index 79e5457..df2b431 100644
--- a/src/nvim/macros.h
+++ b/src/nvim/macros.h
@@ -158,4 +158,7 @@
#define RGB(r, g, b) ((r << 16) | (g << 8) | b)
+#define STR_(x) #x
+#define STR(x) STR_(x)
+
#endif // NVIM_MACROS_H
diff --git a/src/nvim/tui/input.c b/src/nvim/tui/input.c
index 9dc6642..70d87a7 100644
--- a/src/nvim/tui/input.c
+++ b/src/nvim/tui/input.c
@@ -319,8 +319,6 @@ static bool handle_forced_escape(TermInput *input)
return false;
}
-static void restart_reading(void **argv);
-
static void read_cb(Stream *stream, RBuffer *buf, size_t c, void *data,
bool eof)
{
diff --git a/src/nvim/tui/tui.c b/src/nvim/tui/tui.c
index 5e30517..69d7533 100644
--- a/src/nvim/tui/tui.c
+++ b/src/nvim/tui/tui.c
@@ -11,6 +11,7 @@
#include "nvim/lib/kvec.h"
#include "nvim/vim.h"
+#include "nvim/log.h"
#include "nvim/ui.h"
#include "nvim/map.h"
#include "nvim/main.h"
@@ -32,6 +33,8 @@
#define CNORM_COMMAND_MAX_SIZE 32
#define OUTBUF_SIZE 0xffff
+#define TOO_MANY_EVENTS 1000000
+
typedef struct {
int top, bot, left, right;
} Rect;
@@ -587,6 +590,18 @@ static void tui_flush(UI *ui)
TUIData *data = ui->data;
UGrid *grid = &data->grid;
+ size_t nrevents = loop_size(data->loop);
+ if (nrevents > TOO_MANY_EVENTS) {
+ ILOG("TUI event-queue flooded (thread_events=%zu); purging", nrevents);
+ // Back-pressure: UI events may accumulate much faster than the terminal
+ // device can serve them. Even if SIGINT/CTRL-C is received, user must still
+ // wait for the TUI event-queue to drain, and if there are ~millions of
+ // events in the queue, it could take hours. Clearing the queue allows the
+ // UI to recover. #1234 #5396
+ loop_purge(data->loop);
+ tui_busy_stop(ui); // avoid hidden cursor
+ }
+
while (kv_size(data->invalid_regions)) {
Rect r = kv_pop(data->invalid_regions);
int currow = -1;
diff --git a/src/nvim/ui.c b/src/nvim/ui.c
index 549ed8a..6dad0c4 100644
--- a/src/nvim/ui.c
+++ b/src/nvim/ui.c
@@ -88,18 +88,17 @@ void ui_builtin_start(void)
#ifdef FEAT_TUI
tui_start();
#else
- fprintf(stderr, "Neovim was built without a Terminal UI," \
- "press Ctrl+C to exit\n");
-
+ fprintf(stderr, "Nvim headless-mode started.\n");
size_t len;
char **addrs = server_address_list(&len);
if (addrs != NULL) {
- fprintf(stderr, "currently listening on the following address(es)\n");
+ fprintf(stderr, "Listening on:\n");
for (size_t i = 0; i < len; i++) {
fprintf(stderr, "\t%s\n", addrs[i]);
}
xfree(addrs);
}
+ fprintf(stderr, "Press CTRL+C to exit.\n");
#endif
}
diff --git a/src/nvim/ui_bridge.c b/src/nvim/ui_bridge.c
index cc27c73..25861ab 100644
--- a/src/nvim/ui_bridge.c
+++ b/src/nvim/ui_bridge.c
@@ -1,11 +1,12 @@
-// UI wrapper that sends UI requests to the UI thread.
-// Used by the built-in TUI and external libnvim-based UIs.
+// UI wrapper that sends requests to the UI thread.
+// Used by the built-in TUI and libnvim-based UIs.
#include <assert.h>
#include <stdbool.h>
#include <stdio.h>
#include <limits.h>
+#include "nvim/log.h"
#include "nvim/main.h"
#include "nvim/vim.h"
#include "nvim/ui.h"
@@ -19,10 +20,30 @@
#define UI(b) (((UIBridgeData *)b)->ui)
-// Call a function in the UI thread
+#if MIN_LOG_LEVEL <= DEBUG_LOG_LEVEL
+static size_t uilog_seen = 0;
+static argv_callback uilog_event = NULL;
+#define UI_CALL(ui, name, argc, ...) \
+ do { \
+ if (uilog_event == ui_bridge_##name##_event) { \
+ uilog_seen++; \
+ } else { \
+ if (uilog_seen > 0) { \
+ DLOG("UI bridge: ...%zu times", uilog_seen); \
+ } \
+ DLOG("UI bridge: " STR(name)); \
+ uilog_seen = 0; \
+ uilog_event = ui_bridge_##name##_event; \
+ } \
+ ((UIBridgeData *)ui)->scheduler( \
+ event_create(1, ui_bridge_##name##_event, argc, __VA_ARGS__), UI(ui)); \
+ } while (0)
+#else
+// Schedule a function call on the UI bridge thread.
#define UI_CALL(ui, name, argc, ...) \
((UIBridgeData *)ui)->scheduler( \
event_create(1, ui_bridge_##name##_event, argc, __VA_ARGS__), UI(ui))
+#endif
#define INT2PTR(i) ((void *)(uintptr_t)i)
#define PTR2INT(p) ((int)(uintptr_t)p)
@@ -218,16 +239,16 @@ static void ui_bridge_mode_change_event(void **argv)
}
static void ui_bridge_set_scroll_region(UI *b, int top, int bot, int left,
- int right)
+ int right)
{
UI_CALL(b, set_scroll_region, 5, b, INT2PTR(top), INT2PTR(bot),
- INT2PTR(left), INT2PTR(right));
+ INT2PTR(left), INT2PTR(right));
}
static void ui_bridge_set_scroll_region_event(void **argv)
{
UI *ui = UI(argv[0]);
ui->set_scroll_region(ui, PTR2INT(argv[1]), PTR2INT(argv[2]),
- PTR2INT(argv[3]), PTR2INT(argv[4]));
+ PTR2INT(argv[3]), PTR2INT(argv[4]));
}
static void ui_bridge_scroll(UI *b, int count)
diff --git a/src/nvim/ui_bridge.h b/src/nvim/ui_bridge.h
index 9e4bf9f..dba4615 100644
--- a/src/nvim/ui_bridge.h
+++ b/src/nvim/ui_bridge.h
@@ -1,5 +1,5 @@
// Bridge for communication between a UI thread and nvim core.
-// Used by the built-in TUI and external libnvim-based UIs.
+// Used by the built-in TUI and libnvim-based UIs.
#ifndef NVIM_UI_BRIDGE_H
#define NVIM_UI_BRIDGE_H
diff --git a/src/nvim/version.c b/src/nvim/version.c
index 82a6f5f..1db45f5 100644
--- a/src/nvim/version.c
+++ b/src/nvim/version.c
@@ -13,6 +13,7 @@
#include "nvim/iconv.h"
#include "nvim/version.h"
#include "nvim/charset.h"
+#include "nvim/macros.h"
#include "nvim/memline.h"
#include "nvim/memory.h"
#include "nvim/message.h"
@@ -22,9 +23,6 @@
// version info generated by the build system
#include "auto/versiondef.h"
-#define STR_(x) #x
-#define STR(x) STR_(x)
-
// for ":version", ":intro", and "nvim --version"
#ifndef NVIM_VERSION_MEDIUM
#define NVIM_VERSION_MEDIUM STR(NVIM_VERSION_MAJOR) "." STR(NVIM_VERSION_MINOR)\
diff --git a/test/unit/queue_spec.lua b/test/unit/multiqueue_spec.lua
similarity index 81%
rename from test/unit/queue_spec.lua
rename to test/unit/multiqueue_spec.lua
index d802367..c7f8dd8 100644
--- a/test/unit/queue_spec.lua
+++ b/test/unit/multiqueue_spec.lua
@@ -36,6 +36,27 @@ describe("multiqueue (multi-level event-queue)", function()
put(child3, 'c3i2')
end)
+ it('keeps count of added events', function()
+ eq(3, multiqueue.multiqueue_size(child1))
+ eq(4, multiqueue.multiqueue_size(child2))
+ eq(2, multiqueue.multiqueue_size(child3))
+ end)
+
+ it('keeps count of removed events', function()
+ multiqueue.multiqueue_get(child1)
+ eq(2, multiqueue.multiqueue_size(child1))
+ multiqueue.multiqueue_get(child1)
+ eq(1, multiqueue.multiqueue_size(child1))
+ multiqueue.multiqueue_get(child1)
+ eq(0, multiqueue.multiqueue_size(child1))
+ put(child1, 'c2ixx')
+ eq(1, multiqueue.multiqueue_size(child1))
+ multiqueue.multiqueue_get(child1)
+ eq(0, multiqueue.multiqueue_size(child1))
+ multiqueue.multiqueue_get(child1)
+ eq(0, multiqueue.multiqueue_size(child1))
+ end)
+
it('removing from parent removes from child', function()
eq('c1i1', get(parent))
eq('c1i2', get(parent))
--
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