989d921f5d
I'm very pleased to announce the release of our new website and documentation using the new toolchain with Hugo and AsciiDoctor. To get more information about the new toolchain please read the FreeBSD Documentation Project Primer[1], Hugo docs[2] and AsciiDoctor docs[3]. Acknowledgment: Benedict Reuschling <bcr@> Glen Barber <gjb@> Hiroki Sato <hrs@> Li-Wen Hsu <lwhsu@> Sean Chittenden <seanc@> The FreeBSD Foundation [1] https://docs.FreeBSD.org/en/books/fdp-primer/ [2] https://gohugo.io/documentation/ [3] https://docs.asciidoctor.org/home/ Approved by: doceng, core
82 lines
2.3 KiB
Diff
82 lines
2.3 KiB
Diff
Index: lib/libc/stdlib/malloc.c
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===================================================================
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RCS file: /home/ncvs/src/lib/libc/stdlib/malloc.c,v
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retrieving revision 1.147.2.6.2.1
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retrieving revision 1.147.2.7
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diff -p -I __FBSDID -I $FreeBSD -u -r1.147.2.6.2.1 -r1.147.2.7
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--- lib/libc/stdlib/malloc.c 15 Apr 2009 03:14:26 -0000 1.147.2.6.2.1
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+++ lib/libc/stdlib/malloc.c 3 May 2009 17:51:38 -0000 1.147.2.7
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@@ -4715,16 +4715,41 @@ _malloc_thread_cleanup(void)
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void
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_malloc_prefork(void)
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{
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- unsigned i;
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+ bool again;
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+ unsigned i, j;
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+ arena_t *larenas[narenas], *tarenas[narenas];
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/* Acquire all mutexes in a safe order. */
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- malloc_spin_lock(&arenas_lock);
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- for (i = 0; i < narenas; i++) {
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- if (arenas[i] != NULL)
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- malloc_spin_lock(&arenas[i]->lock);
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- }
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- malloc_spin_unlock(&arenas_lock);
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+ /*
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+ * arenas_lock must be acquired after all of the arena mutexes, in
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+ * order to avoid potential deadlock with arena_lock_balance[_hard]().
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+ * Since arenas_lock protects the arenas array, the following code has
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+ * to race with arenas_extend() callers until it succeeds in locking
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+ * all arenas before locking arenas_lock.
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+ */
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+ memset(larenas, 0, sizeof(arena_t *) * narenas);
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+ do {
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+ again = false;
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+
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+ malloc_spin_lock(&arenas_lock);
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+ for (i = 0; i < narenas; i++) {
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+ if (arenas[i] != larenas[i]) {
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+ memcpy(tarenas, arenas, sizeof(arena_t *) *
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+ narenas);
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+ malloc_spin_unlock(&arenas_lock);
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+ for (j = 0; j < narenas; j++) {
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+ if (larenas[j] != tarenas[j]) {
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+ larenas[j] = tarenas[j];
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+ malloc_spin_lock(
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+ &larenas[j]->lock);
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+ }
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+ }
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+ again = true;
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+ break;
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+ }
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+ }
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+ } while (again);
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malloc_mutex_lock(&base_mtx);
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@@ -4739,6 +4764,7 @@ void
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_malloc_postfork(void)
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{
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unsigned i;
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+ arena_t *larenas[narenas];
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/* Release all mutexes, now that fork() has completed. */
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@@ -4750,12 +4776,12 @@ _malloc_postfork(void)
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malloc_mutex_unlock(&base_mtx);
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- malloc_spin_lock(&arenas_lock);
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+ memcpy(larenas, arenas, sizeof(arena_t *) * narenas);
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+ malloc_spin_unlock(&arenas_lock);
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for (i = 0; i < narenas; i++) {
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- if (arenas[i] != NULL)
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- malloc_spin_unlock(&arenas[i]->lock);
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+ if (larenas[i] != NULL)
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+ malloc_spin_unlock(&larenas[i]->lock);
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}
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- malloc_spin_unlock(&arenas_lock);
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}
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/*
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