74 lines
1.7 KiB
Diff
74 lines
1.7 KiB
Diff
From cd8c5d70d4358aee3dc9fee53e9870d0501cc6db Mon Sep 17 00:00:00 2001
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From: Milian Wolff <mail@milianw.de>
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Date: Fri, 4 May 2018 21:55:52 +0200
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Subject: [PATCH 23/50] Optionally use a thread-local cache for valid memory
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When libunwind is compiled with per-thread-caches, then also
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make the cache of valid memory addresses thread-local.
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---
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src/x86_64/Ginit.c | 40 +++++++++++++++++++++++++++++++++++++++-
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1 file changed, 39 insertions(+), 1 deletion(-)
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diff --git a/src/x86_64/Ginit.c b/src/x86_64/Ginit.c
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index 21d8c49..669e9ed 100644
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--- a/src/x86_64/Ginit.c
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+++ b/src/x86_64/Ginit.c
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@@ -174,8 +174,45 @@ tdep_init_mem_validate (void)
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}
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/* Cache of already validated addresses */
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-#if HAVE_ATOMIC_OPS_H
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+#if defined(HAVE___THREAD) && HAVE___THREAD
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#define NLGA 4
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+// thread-local variant
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+static __thread unw_word_t last_good_addr[NLGA];
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+static __thread int lga_victim;
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+
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+static int
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+is_cached_valid_mem(unw_word_t addr)
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+{
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+ int i;
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+ for (i = 0; i < NLGA; i++)
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+ {
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+ if (addr == &last_good_addr[i])
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+ return 1;
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+ }
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+ return 0;
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+}
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+
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+static void
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+cache_valid_mem(unw_word_t addr)
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+{
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+ int i, victim;
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+ victim = lga_victim;
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+ for (i = 0; i < NLGA; i++) {
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+ if (last_good_addr[victim] == 0) {
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+ last_good_addr[victim] = addr;
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+ return;
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+ }
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+ victim = (victim + 1) % NLGA;
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+ }
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+
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+ /* All slots full. Evict the victim. */
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+ last_good_addr[victim] = addr;
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+ victim = (victim + 1) % NLGA;
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+ lga_victim = victim;
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+}
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+
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+#elif HAVE_ATOMIC_OPS_H
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+// global, thread safe variant
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static AO_T last_good_addr[NLGA];
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static AO_T lga_victim;
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@@ -209,6 +246,7 @@ cache_valid_mem(unw_word_t addr)
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AO_store(&lga_victim, victim);
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}
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#else
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+// disabled, no cache
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static int
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is_cached_valid_mem(unw_word_t addr UNUSED)
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{
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--
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1.8.3.1
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