From 7bf2db4c2ae30c0f7b320e57060715bf6279e98a Mon Sep 17 00:00:00 2001 From: Dan Cross Date: Thu, 16 Jan 2020 16:54:19 +0000 Subject: malloc: remove locking The issue manifests in fork: POSIX fork mandates that a fork'd process is created with a single thread. If a multithreaded program forks, and some thread was in malloc() when the fork() happened, then in the child the lock will be held but there will be no thread to release it. We assume the system malloc() must already know how to deal with this and is thread-safe, but it won't know about our custom spinlock. Judging that this is no longer necessary (the lock code was added 15 years ago) we remove it. Signed-off-by: Dan Cross --- src/cmd/9term/malloc.c | 10 ---------- 1 file changed, 10 deletions(-) (limited to 'src/cmd/9term') diff --git a/src/cmd/9term/malloc.c b/src/cmd/9term/malloc.c index 9132235b..7b590bc4 100644 --- a/src/cmd/9term/malloc.c +++ b/src/cmd/9term/malloc.c @@ -7,8 +7,6 @@ #define NOPLAN9DEFINES #include -static Lock malloclock; - void* p9malloc(ulong n) { @@ -16,9 +14,7 @@ p9malloc(ulong n) if(n == 0) n++; - lock(&malloclock); v = malloc(n); - unlock(&malloclock); print("p9malloc %lud => %p; pc %lux\n", n, v, getcallerpc(&n)); return v; } @@ -28,10 +24,8 @@ p9free(void *v) { if(v == nil) return; - lock(&malloclock); print("p9free %p; pc %lux\n", v, getcallerpc(&v)); free(v); - unlock(&malloclock); } void* @@ -42,9 +36,7 @@ p9calloc(ulong a, ulong b) if(a*b == 0) a = b = 1; - lock(&malloclock); v = calloc(a*b, 1); - unlock(&malloclock); print("p9calloc %lud %lud => %p; pc %lux\n", a, b, v, getcallerpc(&a)); return v; } @@ -54,9 +46,7 @@ p9realloc(void *v, ulong n) { void *vv; - lock(&malloclock); vv = realloc(v, n); - unlock(&malloclock); print("p9realloc %p %lud => %p; pc %lux\n", v, n, vv, getcallerpc(&v)); return vv; } -- cgit v1.2.3