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Fix many thread and file descriptor issues on Windows

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The greenbean web server now works nearly perfectly on Windows with over
1000 threads. But some synchronization issues still remain which prevent
us from going over nine thousand.
This commit is contained in:
Justine Tunney 2022-05-20 18:51:41 -07:00
parent 96781d0679
commit 7838edae88
32 changed files with 363 additions and 192 deletions
Download patch file Download diff file Expand all files Collapse all files

58
libc/calls/reservefd.c
View file

@ -29,33 +29,38 @@
#include "libc/str/str.h"
#include "libc/sysv/errfuns.h"
// XXX: until we can add read locks to all the code that uses g_fds.p
// (right now we only have write locks) we need to keep old copies
// of g_fds.p around after it's been extended, so that threads
// which are using an fd they de facto own can continue reading
static void FreeOldFdsArray(void *p) {
weaken(free)(p);
}
/**
* Grows file descriptor array memory if needed.
*/
int __ensurefds_unlocked(int fd) {
size_t n1, n2;
struct Fd *p1, *p2;
if (fd < g_fds.n) return fd;
STRACE("__ensurefds(%d) extending", fd);
if (!weaken(malloc)) return emfile();
p1 = g_fds.p;
n1 = g_fds.n;
if (fd >= n1) {
STRACE("__ensurefds(%d) extending", fd);
if (weaken(malloc)) {
// TODO(jart): we need a semaphore for this
p1 = g_fds.p;
n2 = fd + (fd >> 1);
if ((p2 = weaken(malloc)(n2 * sizeof(*p1)))) {
memcpy(p2, p1, n1 * sizeof(*p1));
g_fds.p = p2;
g_fds.n = n2;
if (p1 != g_fds.__init_p) {
__cxa_atexit(free, p1, 0);
}
} else {
fd = enomem();
}
} else {
fd = emfile();
}
if (p1 == g_fds.__init_p) {
if (!(p2 = weaken(malloc)(sizeof(g_fds.__init_p)))) return -1;
memcpy(p2, p1, sizeof(g_fds.__init_p));
g_fds.p = p1 = p2;
}
n2 = n1;
while (n2 <= fd) n2 *= 2;
if (!(p2 = weaken(malloc)(n2 * sizeof(*p1)))) return -1;
__cxa_atexit(FreeOldFdsArray, p1, 0);
memcpy(p2, p1, n1 * sizeof(*p1));
bzero(p2 + n1, (p2 + n2) - (p2 + n1));
g_fds.p = p2;
g_fds.n = n2;
return fd;
}
@ -74,7 +79,7 @@ int __ensurefds(int fd) {
*/
int __reservefd_unlocked(int start) {
int fd;
for (fd = g_fds.f; fd < g_fds.n; ++fd) {
for (fd = MAX(start, g_fds.f); fd < g_fds.n; ++fd) {
if (!g_fds.p[fd].kind) {
break;
}
@ -100,10 +105,10 @@ int __reservefd(int start) {
* Closes non-stdio file descriptors to free dynamic memory.
*/
static void FreeFds(void) {
int i;
NTTRACE("FreeFds()");
int i, keep = 3;
STRACE("FreeFds()");
_spinlock(&__fds_lock);
for (i = 3; i < g_fds.n; ++i) {
for (i = keep; i < g_fds.n; ++i) {
if (g_fds.p[i].kind) {
_spunlock(&__fds_lock);
close(i);
@ -111,8 +116,11 @@ static void FreeFds(void) {
}
}
if (g_fds.p != g_fds.__init_p) {
memcpy(g_fds.__init_p, g_fds.p, sizeof(*g_fds.p) * 3);
weaken(free)(g_fds.p);
bzero(g_fds.__init_p, sizeof(g_fds.__init_p));
memcpy(g_fds.__init_p, g_fds.p, sizeof(*g_fds.p) * keep);
if (weaken(free)) {
weaken(free)(g_fds.p);
}
g_fds.p = g_fds.__init_p;
g_fds.n = ARRAYLEN(g_fds.__init_p);
}