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[t:4283] #4283 Merge changeset 37990 from mysql.branches/5.2.3/newbrt/cachetable.c to improve threadsafety checks for critical regions during which a checkpoint is not permitted to begin.

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git-svn-id: file:///svn/toku/tokudb@37991 c7de825b-a66e-492c-adef-691d508d4ae1
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Barry Perlman 2013-04-17 00:00:01 -04:00 • committed by Yoni Fogel
parent cc30d40a79
commit 95f96be914
1 changed files with 12 additions and 12 deletions
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24
newbrt/cachetable.c
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@ -169,8 +169,9 @@ struct cachetable {
KIBBUTZ kibbutz; // another pool of worker threads and jobs to do asynchronously.
LSN lsn_of_checkpoint_in_progress;
uint64_t checkpoint_sequence_number; // just a free-running sequence number, used for detecting threadsafety bugs
uint64_t checkpoint_prohibited; // nonzero when checkpoints are prohibited, used for detecting threadsafety bugs
// Variables used to detect threadsafety bugs are declared volatile to prevent compiler from using thread-local cache.
volatile BOOL checkpoint_is_beginning; // TRUE during begin_checkpoint(), used for detecting threadsafety bugs
volatile uint64_t checkpoint_prohibited; // nonzero when checkpoints are prohibited, used for detecting threadsafety bugs
u_int32_t checkpoint_num_files; // how many cachefiles are in the checkpoint
u_int32_t checkpoint_num_txns; // how many transactions are in the checkpoint
PAIR pending_head; // list of pairs marked with checkpoint_pending
@ -200,14 +201,13 @@ struct cachetable {
// Code bracketed with {BEGIN_CRITICAL_REGION; ... END_CRITICAL_REGION;} macros
// are critical regions in which a checkpoint is not permitted to begin.
#define BEGIN_CRITICAL_REGION {uint64_t cp_seqnum = ct->checkpoint_sequence_number; \
__sync_fetch_and_add(&ct->checkpoint_prohibited, 1);
#define END_CRITICAL_REGION invariant(cp_seqnum == ct->checkpoint_sequence_number); \
invariant(ct->checkpoint_prohibited > 0); \
__sync_fetch_and_sub(&ct->checkpoint_prohibited, 1); }
// Must increment checkpoint_prohibited before testing checkpoint_is_beginning
// on entry to critical region.
#define BEGIN_CRITICAL_REGION {__sync_fetch_and_add(&ct->checkpoint_prohibited, 1); invariant(!ct->checkpoint_is_beginning);}
// Testing checkpoint_prohibited at end of critical region is just belt-and-suspenders redundancy,
// verifying that we just incremented it with the matching BEGIN macro.
#define END_CRITICAL_REGION {invariant(ct->checkpoint_prohibited > 0); __sync_fetch_and_sub(&ct->checkpoint_prohibited, 1);}
// Lock the cachetable
@ -3165,8 +3165,8 @@ toku_cachetable_begin_checkpoint (CACHETABLE ct, TOKULOGGER logger) {
assert(r==0);
}
cachetable_lock(ct);
invariant(ct->checkpoint_prohibited == 0); // detect threadsafety bugs
ct->checkpoint_sequence_number++;
ct->checkpoint_is_beginning = TRUE; // detect threadsafety bugs, must set checkpoint_is_beginning ...
invariant(ct->checkpoint_prohibited == 0); // ... before testing checkpoint_prohibited
//Initialize accountability counters
ct->checkpoint_num_files = 0;
ct->checkpoint_num_txns = 0;
@ -3294,7 +3294,7 @@ toku_cachetable_begin_checkpoint (CACHETABLE ct, TOKULOGGER logger) {
}
cachefiles_unlock(ct);
}
ct->checkpoint_is_beginning = FALSE; // clear before releasing cachetable lock
cachetable_unlock(ct);
}
return 0;