Mercurial > hg > graal-compiler
diff src/share/vm/code/nmethod.cpp @ 2360:fc5ebbb2d1a8
Merge
author | twisti |
---|---|
date | Fri, 18 Mar 2011 01:44:15 -0700 |
parents | 1c0cf339481b 65f880e2869b |
children | d673ef06fe96 |
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--- a/src/share/vm/code/nmethod.cpp Thu Mar 17 18:29:18 2011 -0700 +++ b/src/share/vm/code/nmethod.cpp Fri Mar 18 01:44:15 2011 -0700 @@ -170,7 +170,7 @@ int pc_desc_resets; // number of resets (= number of caches) int pc_desc_queries; // queries to nmethod::find_pc_desc int pc_desc_approx; // number of those which have approximate true - int pc_desc_repeats; // number of _last_pc_desc hits + int pc_desc_repeats; // number of _pc_descs[0] hits int pc_desc_hits; // number of LRU cache hits int pc_desc_tests; // total number of PcDesc examinations int pc_desc_searches; // total number of quasi-binary search steps @@ -278,40 +278,44 @@ void PcDescCache::reset_to(PcDesc* initial_pc_desc) { if (initial_pc_desc == NULL) { - _last_pc_desc = NULL; // native method + _pc_descs[0] = NULL; // native method; no PcDescs at all return; } NOT_PRODUCT(++nmethod_stats.pc_desc_resets); // reset the cache by filling it with benign (non-null) values assert(initial_pc_desc->pc_offset() < 0, "must be sentinel"); - _last_pc_desc = initial_pc_desc + 1; // first valid one is after sentinel for (int i = 0; i < cache_size; i++) _pc_descs[i] = initial_pc_desc; } PcDesc* PcDescCache::find_pc_desc(int pc_offset, bool approximate) { NOT_PRODUCT(++nmethod_stats.pc_desc_queries); - NOT_PRODUCT(if (approximate) ++nmethod_stats.pc_desc_approx); + NOT_PRODUCT(if (approximate) ++nmethod_stats.pc_desc_approx); + + // Note: one might think that caching the most recently + // read value separately would be a win, but one would be + // wrong. When many threads are updating it, the cache + // line it's in would bounce between caches, negating + // any benefit. // In order to prevent race conditions do not load cache elements // repeatedly, but use a local copy: PcDesc* res; - // Step one: Check the most recently returned value. - res = _last_pc_desc; - if (res == NULL) return NULL; // native method; no PcDescs at all + // Step one: Check the most recently added value. + res = _pc_descs[0]; + if (res == NULL) return NULL; // native method; no PcDescs at all if (match_desc(res, pc_offset, approximate)) { NOT_PRODUCT(++nmethod_stats.pc_desc_repeats); return res; } - // Step two: Check the LRU cache. - for (int i = 0; i < cache_size; i++) { + // Step two: Check the rest of the LRU cache. + for (int i = 1; i < cache_size; ++i) { res = _pc_descs[i]; - if (res->pc_offset() < 0) break; // optimization: skip empty cache + if (res->pc_offset() < 0) break; // optimization: skip empty cache if (match_desc(res, pc_offset, approximate)) { NOT_PRODUCT(++nmethod_stats.pc_desc_hits); - _last_pc_desc = res; // record this cache hit in case of repeat return res; } } @@ -322,24 +326,23 @@ void PcDescCache::add_pc_desc(PcDesc* pc_desc) { NOT_PRODUCT(++nmethod_stats.pc_desc_adds); - // Update the LRU cache by shifting pc_desc forward: + // Update the LRU cache by shifting pc_desc forward. for (int i = 0; i < cache_size; i++) { PcDesc* next = _pc_descs[i]; _pc_descs[i] = pc_desc; pc_desc = next; } - // Note: Do not update _last_pc_desc. It fronts for the LRU cache. } // adjust pcs_size so that it is a multiple of both oopSize and // sizeof(PcDesc) (assumes that if sizeof(PcDesc) is not a multiple // of oopSize, then 2*sizeof(PcDesc) is) -static int adjust_pcs_size(int pcs_size) { +static int adjust_pcs_size(int pcs_size) { int nsize = round_to(pcs_size, oopSize); if ((nsize % sizeof(PcDesc)) != 0) { nsize = pcs_size + sizeof(PcDesc); } - assert((nsize % oopSize) == 0, "correct alignment"); + assert((nsize % oopSize) == 0, "correct alignment"); return nsize; } @@ -1180,14 +1183,17 @@ set_stack_traversal_mark(NMethodSweeper::traversal_count()); } -// Tell if a non-entrant method can be converted to a zombie (i.e., there is no activations on the stack) +// Tell if a non-entrant method can be converted to a zombie (i.e., +// there are no activations on the stack, not in use by the VM, +// and not in use by the ServiceThread) bool nmethod::can_not_entrant_be_converted() { assert(is_not_entrant(), "must be a non-entrant method"); // Since the nmethod sweeper only does partial sweep the sweeper's traversal // count can be greater than the stack traversal count before it hits the // nmethod for the second time. - return stack_traversal_mark()+1 < NMethodSweeper::traversal_count(); + return stack_traversal_mark()+1 < NMethodSweeper::traversal_count() && + !is_locked_by_vm(); } void nmethod::inc_decompile_count() { @@ -1294,6 +1300,7 @@ // Common functionality for both make_not_entrant and make_zombie bool nmethod::make_not_entrant_or_zombie(unsigned int state) { assert(state == zombie || state == not_entrant, "must be zombie or not_entrant"); + assert(!is_zombie(), "should not already be a zombie"); // Make sure neither the nmethod nor the method is flushed in case of a safepoint in code below. nmethodLocker nml(this); @@ -1301,11 +1308,6 @@ No_Safepoint_Verifier nsv; { - // If the method is already zombie there is nothing to do - if (is_zombie()) { - return false; - } - // invalidate osr nmethod before acquiring the patching lock since // they both acquire leaf locks and we don't want a deadlock. // This logic is equivalent to the logic below for patching the @@ -1375,13 +1377,12 @@ flush_dependencies(NULL); } - { - // zombie only - if a JVMTI agent has enabled the CompiledMethodUnload event - // and it hasn't already been reported for this nmethod then report it now. - // (the event may have been reported earilier if the GC marked it for unloading). - Pause_No_Safepoint_Verifier pnsv(&nsv); - post_compiled_method_unload(); - } + // zombie only - if a JVMTI agent has enabled the CompiledMethodUnload + // event and it hasn't already been reported for this nmethod then + // report it now. The event may have been reported earilier if the GC + // marked it for unloading). JvmtiDeferredEventQueue support means + // we no longer go to a safepoint here. + post_compiled_method_unload(); #ifdef ASSERT // It's no longer safe to access the oops section since zombie @@ -1566,7 +1567,7 @@ if (_jmethod_id != NULL && JvmtiExport::should_post_compiled_method_unload()) { assert(!unload_reported(), "already unloaded"); JvmtiDeferredEvent event = - JvmtiDeferredEvent::compiled_method_unload_event( + JvmtiDeferredEvent::compiled_method_unload_event(this, _jmethod_id, insts_begin()); if (SafepointSynchronize::is_at_safepoint()) { // Don't want to take the queueing lock. Add it as pending and @@ -2171,10 +2172,12 @@ lock_nmethod(_nm); } -void nmethodLocker::lock_nmethod(nmethod* nm) { +// Only JvmtiDeferredEvent::compiled_method_unload_event() +// should pass zombie_ok == true. +void nmethodLocker::lock_nmethod(nmethod* nm, bool zombie_ok) { if (nm == NULL) return; Atomic::inc(&nm->_lock_count); - guarantee(!nm->is_zombie(), "cannot lock a zombie method"); + guarantee(zombie_ok || !nm->is_zombie(), "cannot lock a zombie method"); } void nmethodLocker::unlock_nmethod(nmethod* nm) {