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Backport epoll memory fix for bug 2839240

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svn:r1430
This commit is contained in:
Nick Mathewson 2009-09-11 18:55:12 +00:00
parent 81765181c6
commit 1bf18e5a06
2 changed files with 26 additions and 20 deletions
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2
ChangeLog
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@ -1,5 +1,7 @@
Changes in 1.4.13-stable: Changes in 1.4.13-stable:
o If the kernel tells us that there are a negative number of bytes to read from a socket, do not believe it. Fixes bug 2841177; found by Alexander Pronchenkov. o If the kernel tells us that there are a negative number of bytes to read from a socket, do not believe it. Fixes bug 2841177; found by Alexander Pronchenkov.
o Do not allocate the maximum event queue and fd array for the epoll backend at startup. Instead, start out accepting 32 events at a time, and double the queue's size when it seems that the OS is generating events faster than we're requesting them. Saves up to 512K per epoll-based event_base. Resolves bug 2839240.
Changes in 1.4.12-stable: Changes in 1.4.12-stable:
o Try to contain degree of failure when running on a win32 version so heavily firewalled that we can't fake a socketpair. o Try to contain degree of failure when running on a win32 version so heavily firewalled that we can't fake a socketpair.

44
epoll.c
View File

@ -94,8 +94,6 @@ const struct eventop epollops = {
#define FD_CLOSEONEXEC(x) #define FD_CLOSEONEXEC(x)
#endif #endif
#define NEVENT 32000
/* On Linux kernels at least up to 2.6.24.4, epoll can't handle timeout /* On Linux kernels at least up to 2.6.24.4, epoll can't handle timeout
* values bigger than (LONG_MAX - 999ULL)/HZ. HZ in the wild can be * values bigger than (LONG_MAX - 999ULL)/HZ. HZ in the wild can be
* as big as 1000, and LONG_MAX can be as small as (1<<31)-1, so the * as big as 1000, and LONG_MAX can be as small as (1<<31)-1, so the
@ -104,30 +102,22 @@ const struct eventop epollops = {
*/ */
#define MAX_EPOLL_TIMEOUT_MSEC (35*60*1000) #define MAX_EPOLL_TIMEOUT_MSEC (35*60*1000)
#define INITIAL_NFILES 32
#define INITIAL_NEVENTS 32
#define MAX_NEVENTS 4096
static void * static void *
epoll_init(struct event_base *base) epoll_init(struct event_base *base)
{ {
int epfd, nfiles = NEVENT; int epfd;
struct rlimit rl;
struct epollop *epollop; struct epollop *epollop;
/* Disable epollueue when this environment variable is set */ /* Disable epollueue when this environment variable is set */
if (getenv("EVENT_NOEPOLL")) if (getenv("EVENT_NOEPOLL"))
return (NULL); return (NULL);
if (getrlimit(RLIMIT_NOFILE, &rl) == 0 &&
rl.rlim_cur != RLIM_INFINITY) {
/*
* Solaris is somewhat retarded - it's important to drop
* backwards compatibility when making changes. So, don't
* dare to put rl.rlim_cur here.
*/
nfiles = rl.rlim_cur - 1;
}
/* Initalize the kernel queue */ /* Initalize the kernel queue */
if ((epfd = epoll_create(32000)) == -1) {
if ((epfd = epoll_create(nfiles)) == -1) {
if (errno != ENOSYS) if (errno != ENOSYS)
event_warn("epoll_create"); event_warn("epoll_create");
return (NULL); return (NULL);
@ -141,20 +131,20 @@ epoll_init(struct event_base *base)
epollop->epfd = epfd; epollop->epfd = epfd;
/* Initalize fields */ /* Initalize fields */
epollop->events = malloc(nfiles * sizeof(struct epoll_event)); epollop->events = malloc(INITIAL_NEVENTS * sizeof(struct epoll_event));
if (epollop->events == NULL) { if (epollop->events == NULL) {
free(epollop); free(epollop);
return (NULL); return (NULL);
} }
epollop->nevents = nfiles; epollop->nevents = INITIAL_NEVENTS;
epollop->fds = calloc(nfiles, sizeof(struct evepoll)); epollop->fds = calloc(INITIAL_NFILES, sizeof(struct evepoll));
if (epollop->fds == NULL) { if (epollop->fds == NULL) {
free(epollop->events); free(epollop->events);
free(epollop); free(epollop);
return (NULL); return (NULL);
} }
epollop->nfds = nfiles; epollop->nfds = INITIAL_NFILES;
evsignal_init(base); evsignal_init(base);
@ -252,6 +242,20 @@ epoll_dispatch(struct event_base *base, void *arg, struct timeval *tv)
event_active(evwrite, EV_WRITE, 1); event_active(evwrite, EV_WRITE, 1);
} }
if (res == epollop->nevents && epollop->nevents < MAX_NEVENTS) {
/* We used all of the event space this time. We should
be ready for more events next time. */
int new_nevents = epollop->nevents * 2;
struct epoll_event *new_events;
new_events = realloc(epollop->events,
new_nevents * sizeof(struct epoll_event));
if (new_events) {
epollop->events = new_events;
epollop->nevents = new_nevents;
}
}
return (0); return (0);
} }