merge work/actors: wasm seed bootstrap (seed/MANIFEST), shared copy-on-write actor memory, top-level hold blocks on all backends and lsp

1 files changed, 85 insertions, 9 deletions

diff --git a/src/micro/port_linux.c b/src/micro/port_linux.c
index 6245f4f..a39e3e8 100644
--- a/src/micro/port_linux.c
+++ b/src/micro/port_linux.c
@@ -38,16 +38,38 @@
 #define VM_TLS
 #endif
 
-/* the machine's memory: a block that grows by realloc, zero in the new part. the
-   base can move on a grow, which micro.c takes into account (it re-reads m). */
+/* the machine's memory. with threads (actors) on a posix host it is one large
+   reservation that grows in place, so that a worker's memory can be a
+   copy-on-write map of a snapshot of its parent (micro_mem_clone); a machine that
+   outgrows the reservation moves to a block that grows by realloc. without threads it
+   is a block that grows by realloc, zero in the new part. the base can move on a
+   grow, which micro.c takes into account (it re-reads m). */
 static VM_TLS Cell *lmem;
 static VM_TLS UCell lcap;
+#if defined(ZY_THREADS) && !defined(_WIN32)
+#include <sys/mman.h>
+#ifdef __linux__
+#include <sys/syscall.h>
+#endif
+#define RESW ((UCell)1 << 28)	/* words reserved per machine: 2 GB of address space */
+static VM_TLS int lres;	/* lmem is a reservation of RESW words */
+static Cell *res_map(void) { void *p = mmap(0, RESW * sizeof(Cell), PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON | MAP_NORESERVE, -1, 0); return p == MAP_FAILED ? 0 : p; }
+#endif
 
 Cell *micro_mem_alloc(UCell words)
 {
 	Cell *n;
 	if (words <= lcap && lmem) return lmem;
 	if (words > ((UCell)-1) / sizeof(Cell)) return NULL;
+#if defined(ZY_THREADS) && !defined(_WIN32)
+	if (!lmem && words <= RESW && (lmem = res_map())) { lres = 1; lcap = words; return lmem; }
+	if (lres && words <= RESW) { lcap = words; return lmem; }	/* the reservation reads zero past lcap */
+	if (lres) {
+		n = malloc(words * sizeof(Cell)); if (!n) return NULL;
+		memcpy(n, lmem, lcap * sizeof(Cell)); memset(n + lcap, 0, (words - lcap) * sizeof(Cell));
+		munmap(lmem, RESW * sizeof(Cell)); lres = 0; lmem = n; lcap = words; return n;
+	}
+#endif
 	n = realloc(lmem, words * sizeof(Cell));
 	if (!n) return NULL;
 	memset(n + lcap, 0, (words - lcap) * sizeof(Cell));
@@ -56,15 +78,62 @@ Cell *micro_mem_alloc(UCell words)
 	return n;
 }
 
+#if defined(ZY_THREADS) && !defined(_WIN32)
+/* a worker's memory is a private map of an unchanging snapshot of its parent's,
+   plus the pages the parent changed since; see the same scheme in src/core/core.c */
+#define SNAP_PAGE 512
+static VM_TLS int snap_fd = -1; static VM_TLS Cell *snap_view; static VM_TLS UCell snap_words;
+static void snap_drop(void) { if (snap_view) munmap(snap_view, snap_words * sizeof(Cell)); if (snap_fd >= 0) close(snap_fd); snap_fd = -1; snap_view = 0; snap_words = 0; }
+static int snap_take(void)
+{
+	UCell words = (lcap + SNAP_PAGE - 1) / SNAP_PAGE * SNAP_PAGE; size_t bytes = words * sizeof(Cell), done = 0; int fd = -1; void *view;
+#ifdef __linux__
+#ifdef SYS_memfd_create
+	fd = (int)syscall(SYS_memfd_create, "zym-snapshot", 1u);
+#endif
+#else
+	{ char name[64]; snprintf(name, sizeof name, "/zym-%d-%p", (int)getpid(), (void *)&name); fd = shm_open(name, O_RDWR | O_CREAT | O_EXCL, 0600); if (fd >= 0) shm_unlink(name); }
+#endif
+	if (fd < 0) return -1;
+	if (ftruncate(fd, (off_t)bytes) < 0) { close(fd); return -1; }
+	while (done < bytes) { ssize_t k = pwrite(fd, (char *)lmem + done, bytes - done, (off_t)done); if (k <= 0) { close(fd); return -1; } done += (size_t)k; }
+	view = mmap(0, bytes, PROT_READ, MAP_SHARED, fd, 0);
+	if (view == MAP_FAILED) { close(fd); return -1; }
+	if (mmap(lmem, bytes, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_FIXED | MAP_NORESERVE, fd, 0) == MAP_FAILED) { munmap(view, bytes); close(fd); return -1; }
+	snap_drop(); snap_fd = fd; snap_view = view; snap_words = words; return 0;
+}
+Cell *micro_mem_clone(void)
+{
+	UCell p, dirty = 0; Cell *c;
+	if (!lres || !lmem) return 0;
+	if (snap_fd >= 0) {
+		for (p = 0; p < lcap; p += SNAP_PAGE) if (p >= snap_words || memcmp(lmem + p, snap_view + p, SNAP_PAGE * sizeof(Cell))) dirty++;
+		if (dirty * 4 > snap_words / SNAP_PAGE) snap_drop();
+	}
+	if (snap_fd < 0 && snap_take() < 0) return 0;
+	c = res_map(); if (!c) return 0;
+	if (mmap(c, snap_words * sizeof(Cell), PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_FIXED | MAP_NORESERVE, snap_fd, 0) == MAP_FAILED) { munmap(c, RESW * sizeof(Cell)); return 0; }
+	for (p = 0; p < lcap; p += SNAP_PAGE) {
+		UCell k = lcap - p < SNAP_PAGE ? lcap - p : SNAP_PAGE;
+		if (p >= snap_words || memcmp(lmem + p, snap_view + p, k * sizeof(Cell))) memcpy(c + p, lmem + p, k * sizeof(Cell));
+	}
+	return c;
+}
+void micro_mem_adopt(Cell *mem, UCell words) { lmem = mem; lcap = words; lres = 1; }
+void micro_mem_release(Cell *mem) { if (mem) munmap(mem, RESW * sizeof(Cell)); }
+#endif
+
 #if defined(ZY_THREADS)
-static VM_TLS unsigned char input_bytes[65536];
+/* allocated when the machine first reads, so a worker that never reads has none */
+static VM_TLS unsigned char *input_buffer;
+#define input_bytes (input_buffer ? input_buffer : (input_buffer = malloc(65536)) ? input_buffer : (fputs("zym: out of memory\n", stderr), exit(2), input_buffer))
 static VM_TLS int input_position, input_count, input_ended;
 static int input_fill(int wait) {
  if (input_position < input_count) return 1;
  if (input_ended) return 0;
  if (!wait) { struct pollfd descriptor = {0, POLLIN, 0}; if (poll(&descriptor, 1, 0) <= 0) return 0; }
  else fflush(stdout);
- int n = (int)read(0, input_bytes, sizeof input_bytes);
+ int n = (int)read(0, input_bytes, 65536);
  if (n <= 0) { input_ended = 1; return 0; }
  input_position = 0; input_count = n; return 1;
 }
@@ -392,22 +461,29 @@ int main(int argc, char **argv) {
 
 #ifdef ZY_THREADS
 struct PortSnapshot {
- unsigned char bytes[65536];
  int position, count, ended, argc, envc;
  char **argv, **envp;
+ unsigned char bytes[];	/* the input read ahead and not consumed yet */
 };
-size_t micro_context_port_size(void) { return sizeof(struct PortSnapshot); }
+size_t micro_context_port_size(void) { return sizeof(struct PortSnapshot) + (size_t)(input_position < input_count ? input_count - input_position : 0); }
 void micro_context_port_save(void *destination) {
  struct PortSnapshot *snapshot = destination;
- memcpy(snapshot->bytes, input_bytes, sizeof input_bytes);
+ if (input_position < input_count) memcpy(snapshot->bytes, input_bytes + input_position, (size_t)(input_count - input_position));
  snapshot->position = input_position; snapshot->count = input_count; snapshot->ended = input_ended;
  snapshot->argc = zy_argc; snapshot->argv = zy_argv; snapshot->envc = zy_envc; snapshot->envp = zy_envp;
 }
 void micro_context_port_restore(const void *source) {
  const struct PortSnapshot *snapshot = source;
- memcpy(input_bytes, snapshot->bytes, sizeof input_bytes);
  input_position = snapshot->position; input_count = snapshot->count; input_ended = snapshot->ended;
+ if (input_position < input_count) memcpy(input_bytes + input_position, snapshot->bytes, (size_t)(input_count - input_position));
  zy_argc = snapshot->argc; zy_argv = snapshot->argv; zy_envc = snapshot->envc; zy_envp = snapshot->envp;
 }
-void micro_context_port_free(void) { free(lmem); lmem = 0; lcap = 0; }
+void micro_context_port_free(void) {
+ free(input_buffer); input_buffer = 0;
+#ifndef _WIN32
+ if (lres) { munmap(lmem, RESW * sizeof(Cell)); lres = 0; snap_drop(); } else
+#endif
+ free(lmem);
+ lmem = 0; lcap = 0;
+}
 #endif