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authorRobert Morris <[email protected]>2014-08-28 05:57:47 -0400
committerRobert Morris <[email protected]>2014-08-28 05:57:47 -0400
commit48aa917403de1599a02924e429a9f43ea31e9cc1 (patch)
tree037648a21b395eacdd2d716a33cfc95e14ff0a61 /log.c
parent71453f72f285a17ccf0520b9dbdafdc701ff2f4a (diff)
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i think this is a working concurrent logging scheme
Diffstat (limited to 'log.c')
-rw-r--r--log.c21
1 files changed, 19 insertions, 2 deletions
diff --git a/log.c b/log.c
index 159df98..9d42ea8 100644
--- a/log.c
+++ b/log.c
@@ -52,6 +52,10 @@ struct log log;
static void recover_from_log(void);
static void commit();
+// statistics, delete eventually XXX.
+static int maxsize;
+static int maxoutstanding;
+
void
initlog(void)
{
@@ -131,10 +135,15 @@ begin_op(void)
while(1){
if(log.committing){
sleep(&log, &log.lock);
+ } else if(log.lh.n + (log.outstanding+1)*MAXOPBLOCKS > LOGSIZE){
+ // this op might exhaust log space; wait for commit.
+ sleep(&log, &log.lock);
} else {
- // XXX wait (for a commit) if log is longish.
- // need to reserve to avoid over-commit of log space.
log.outstanding += 1;
+ if(log.outstanding > maxoutstanding){
+ maxoutstanding = log.outstanding;
+ cprintf("%d outstanding\n", log.outstanding);
+ }
release(&log.lock);
break;
}
@@ -155,6 +164,9 @@ end_op(void)
if(log.outstanding == 0){
do_commit = 1;
log.committing = 1;
+ } else {
+ // begin_op() may be waiting for log space.
+ wakeup(&log);
}
release(&log.lock);
@@ -208,6 +220,11 @@ log_write(struct buf *b)
if (i == log.lh.n)
log.lh.n++;
b->flags |= B_DIRTY; // XXX prevent eviction
+
+ if(log.lh.n > maxsize){
+ maxsize = log.lh.n;
+ cprintf("log size %d/%d\n", log.lh.n, LOGSIZE);
+ }
}
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