From 48aa917403de1599a02924e429a9f43ea31e9cc1 Mon Sep 17 00:00:00 2001
From: Robert Morris <rtm@csail.mit.edu>
Date: Thu, 28 Aug 2014 05:57:47 -0400
Subject: [PATCH] i think this is a working concurrent logging scheme
---
bio.c | 2 +
log.c | 21 +++++-
mkfs.c | 2 +-
param.h | 5 +-
usertests.c | 186 ++++++++++++++++++++++++++--------------------------
5 files changed, 117 insertions(+), 99 deletions(-)
diff --git a/bio.c b/bio.c
index de1d0f2..d2ebc4b 100644
--- a/bio.c
+++ b/bio.c
@@ -80,6 +80,8 @@ bget(uint dev, uint sector)
}
// Not cached; recycle some non-busy and clean buffer.
+ // "clean" because B_DIRTY and !B_BUSY means log.c
+ // hasn't yet committed the changes to the buffer.
for(b = bcache.head.prev; b != &bcache.head; b = b->prev){
if((b->flags & B_BUSY) == 0 && (b->flags & B_DIRTY) == 0){
b->dev = dev;
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);
+ }
}
//PAGEBREAK!
diff --git a/mkfs.c b/mkfs.c
index 4b0e329..c168377 100644
--- a/mkfs.c
+++ b/mkfs.c
@@ -13,7 +13,7 @@
#define static_assert(a, b) do { switch (0) case 0: case (a): ; } while (0)
-int nblocks = 985;
+int nblocks = (995-LOGSIZE);
int nlog = LOGSIZE;
int ninodes = 200;
int size = 1024;
diff --git a/param.h b/param.h
index b6f6f46..bdac60c 100644
--- a/param.h
+++ b/param.h
@@ -3,10 +3,11 @@
#define NCPU 8 // maximum number of CPUs
#define NOFILE 16 // open files per process
#define NFILE 100 // open files per system
-#define NBUF 10 // size of disk block cache
#define NINODE 50 // maximum number of active i-nodes
#define NDEV 10 // maximum major device number
#define ROOTDEV 1 // device number of file system root disk
#define MAXARG 32 // max exec arguments
-#define LOGSIZE 10 // max data sectors in on-disk log
+#define MAXOPBLOCKS 10 // max # of blocks any FS op writes
+#define LOGSIZE (MAXOPBLOCKS*3) // max data sectors in on-disk log
+#define NBUF (MAXOPBLOCKS*3) // size of disk block cache (>= LOGSIZE)
diff --git a/usertests.c b/usertests.c
index 5a78c7c..22a7bfb 100644
--- a/usertests.c
+++ b/usertests.c
@@ -512,51 +512,56 @@ sharedfd(void)
}
}
-// two processes write two different files at the same
+// four processes write different files at the same
// time, to test block allocation.
void
-twofiles(void)
+fourfiles(void)
{
- int fd, pid, i, j, n, total;
+ int fd, pid, i, j, n, total, pi;
+ char *names[] = { "f0", "f1", "f2", "f3" };
char *fname;
- printf(1, "twofiles test\n");
+ printf(1, "fourfiles test\n");
- unlink("f1");
- unlink("f2");
+ for(pi = 0; pi < 4; pi++){
+ fname = names[pi];
+ unlink(fname);
- pid = fork();
- if(pid < 0){
- printf(1, "fork failed\n");
- exit();
- }
+ pid = fork();
+ if(pid < 0){
+ printf(1, "fork failed\n");
+ exit();
+ }
- fname = pid ? "f1" : "f2";
- fd = open(fname, O_CREATE | O_RDWR);
- if(fd < 0){
- printf(1, "create failed\n");
- exit();
- }
-
- memset(buf, pid?'p':'c', 512);
- for(i = 0; i < 12; i++){
- if((n = write(fd, buf, 500)) != 500){
- printf(1, "write failed %d\n", n);
+ if(pid == 0){
+ fd = open(fname, O_CREATE | O_RDWR);
+ if(fd < 0){
+ printf(1, "create failed\n");
+ exit();
+ }
+
+ memset(buf, '0'+pi, 512);
+ for(i = 0; i < 12; i++){
+ if((n = write(fd, buf, 500)) != 500){
+ printf(1, "write failed %d\n", n);
+ exit();
+ }
+ }
exit();
}
}
- close(fd);
- if(pid)
+
+ for(pi = 0; pi < 4; pi++){
wait();
- else
- exit();
+ }
for(i = 0; i < 2; i++){
- fd = open(i?"f1":"f2", 0);
+ fname = names[i];
+ fd = open(fname, 0);
total = 0;
while((n = read(fd, buf, sizeof(buf))) > 0){
for(j = 0; j < n; j++){
- if(buf[j] != (i?'p':'c')){
+ if(buf[j] != '0'+i){
printf(1, "wrong char\n");
exit();
}
@@ -568,87 +573,80 @@ twofiles(void)
printf(1, "wrong length %d\n", total);
exit();
}
+ unlink(fname);
}
- unlink("f1");
- unlink("f2");
-
- printf(1, "twofiles ok\n");
+ printf(1, "fourfiles ok\n");
}
-// two processes create and delete different files in same directory
+// four processes create and delete different files in same directory
void
createdelete(void)
{
enum { N = 20 };
- int pid, i, fd;
+ int pid, i, fd, pi;
char name[32];
printf(1, "createdelete test\n");
- pid = fork();
- if(pid < 0){
- printf(1, "fork failed\n");
- exit();
- }
- name[0] = pid ? 'p' : 'c';
- name[2] = '\0';
- for(i = 0; i < N; i++){
- name[1] = '0' + i;
- fd = open(name, O_CREATE | O_RDWR);
- if(fd < 0){
- printf(1, "create failed\n");
+ for(pi = 0; pi < 4; pi++){
+ pid = fork();
+ if(pid < 0){
+ printf(1, "fork failed\n");
exit();
}
- close(fd);
- if(i > 0 && (i % 2 ) == 0){
- name[1] = '0' + (i / 2);
- if(unlink(name) < 0){
- printf(1, "unlink failed\n");
+
+ if(pid == 0){
+ name[0] = 'p' + pi;
+ name[2] = '\0';
+ for(i = 0; i < N; i++){
+ name[1] = '0' + i;
+ fd = open(name, O_CREATE | O_RDWR);
+ if(fd < 0){
+ printf(1, "create failed\n");
+ exit();
+ }
+ close(fd);
+ if(i > 0 && (i % 2 ) == 0){
+ name[1] = '0' + (i / 2);
+ if(unlink(name) < 0){
+ printf(1, "unlink failed\n");
+ exit();
+ }
+ }
+ }
+ exit();
+ }
+ }
+
+ for(pi = 0; pi < 4; pi++){
+ wait();
+ }
+
+ name[0] = name[1] = name[2] = 0;
+ for(i = 0; i < N; i++){
+ for(pi = 0; pi < 4; pi++){
+ name[0] = 'p' + pi;
+ name[1] = '0' + i;
+ fd = open(name, 0);
+ if((i == 0 || i >= N/2) && fd < 0){
+ printf(1, "oops createdelete %s didn't exist\n", name);
+ exit();
+ } else if((i >= 1 && i < N/2) && fd >= 0){
+ printf(1, "oops createdelete %s did exist\n", name);
exit();
}
+ if(fd >= 0)
+ close(fd);
}
}
- if(pid==0)
- exit();
- else
- wait();
-
for(i = 0; i < N; i++){
- name[0] = 'p';
- name[1] = '0' + i;
- fd = open(name, 0);
- if((i == 0 || i >= N/2) && fd < 0){
- printf(1, "oops createdelete %s didn't exist\n", name);
- exit();
- } else if((i >= 1 && i < N/2) && fd >= 0){
- printf(1, "oops createdelete %s did exist\n", name);
- exit();
+ for(pi = 0; pi < 4; pi++){
+ name[0] = 'p' + i;
+ name[1] = '0' + i;
+ unlink(name);
}
- if(fd >= 0)
- close(fd);
-
- name[0] = 'c';
- name[1] = '0' + i;
- fd = open(name, 0);
- if((i == 0 || i >= N/2) && fd < 0){
- printf(1, "oops createdelete %s didn't exist\n", name);
- exit();
- } else if((i >= 1 && i < N/2) && fd >= 0){
- printf(1, "oops createdelete %s did exist\n", name);
- exit();
- }
- if(fd >= 0)
- close(fd);
- }
-
- for(i = 0; i < N; i++){
- name[0] = 'p';
- name[1] = '0' + i;
- unlink(name);
- name[0] = 'c';
- unlink(name);
}
printf(1, "createdelete ok\n");
@@ -1716,6 +1714,12 @@ main(int argc, char *argv[])
}
close(open("usertests.ran", O_CREATE));
+ createdelete();
+ linkunlink();
+ concreate();
+ fourfiles();
+ sharedfd();
+
bigargtest();
bigwrite();
bigargtest();
@@ -1741,18 +1745,12 @@ main(int argc, char *argv[])
fourteen();
bigfile();
subdir();
- concreate();
- linkunlink();
linktest();
unlinkread();
- createdelete();
- twofiles();
- sharedfd();
dirfile();
iref();
forktest();
bigdir(); // slow
-
exectest();
exit();