martin 98/06/02 05:50:47
Modified: src CHANGES
src/modules/proxy mod_proxy.h proxy_cache.c
Log:
Do Proxy Garbage Collection in background & other proxy garbage fixes
Revision Changes Path
1.881 +5 -0 apache-1.3/src/CHANGES
Index: CHANGES
===================================================================
RCS file: /home/cvs/apache-1.3/src/CHANGES,v
retrieving revision 1.880
retrieving revision 1.881
diff -u -u -r1.880 -r1.881
--- CHANGES 1998/06/02 08:01:49 1.880
+++ CHANGES 1998/06/02 12:50:44 1.881
@@ -1,5 +1,10 @@
Changes with Apache 1.3.1
+ *) Proxy Cache Fixes: account for directory sizes, fork off garbage
collection
+ to continue in background, use predefined types (off_t, size_t, time_t),
+ log the current cache usage percentage at LogLevel debug
+ [Martin Kraemer, based on discussion between Dean Gaudet & Dirk
vanGulik]
+
Changes with Apache 1.3.0
*) Using a type map file as a custom error document was not possible.
1.35 +6 -6 apache-1.3/src/modules/proxy/mod_proxy.h
Index: mod_proxy.h
===================================================================
RCS file: /home/cvs/apache-1.3/src/modules/proxy/mod_proxy.h,v
retrieving revision 1.34
retrieving revision 1.35
diff -u -u -r1.34 -r1.35
--- mod_proxy.h 1998/05/27 22:56:04 1.34
+++ mod_proxy.h 1998/06/02 12:50:46 1.35
@@ -188,11 +188,11 @@
/* static information about the local cache */
struct cache_conf {
const char *root; /* the location of the cache directory
*/
- int space; /* Maximum cache size (in 1024 bytes) */
- int maxexpire; /* Maximum time to keep cached files in secs */
- int defaultexpire; /* default time to keep cached file in
secs */
+ off_t space; /* Maximum cache size (in 1024 bytes) */
+ time_t maxexpire; /* Maximum time to keep cached files in
secs */
+ time_t defaultexpire; /* default time to keep cached file in secs */
double lmfactor; /* factor for estimating expires date */
- int gcinterval; /* garbage collection interval, in seconds */
+ time_t gcinterval; /* garbage collection interval, in
seconds */
int dirlevels; /* Number of levels of subdirectories */
int dirlength; /* Length of subdirectory names */
};
@@ -207,7 +207,7 @@
array_header *nocaches;
char *domain; /* domain name to use in absence of a domain
name in the request */
int req; /* true if proxy requests are enabled */
- int recv_buffer_size;
+ size_t recv_buffer_size;
} proxy_server_conf;
struct hdr_entry {
@@ -229,7 +229,7 @@
time_t lmod; /* last-modified date of cached entity */
time_t date; /* the date the cached file was last touched */
int version; /* update count of the file */
- unsigned int len; /* content length */
+ off_t len; /* content length */
char *protocol; /* Protocol, and major/minor number, e.g.
HTTP/1.1 */
int status; /* the status of the cached file */
char *resp_line; /* the whole status like (protocol, code +
message) */
1.42 +182 -55 apache-1.3/src/modules/proxy/proxy_cache.c
Index: proxy_cache.c
===================================================================
RCS file: /home/cvs/apache-1.3/src/modules/proxy/proxy_cache.c,v
retrieving revision 1.41
retrieving revision 1.42
diff -u -u -r1.41 -r1.42
--- proxy_cache.c 1998/05/29 18:20:58 1.41
+++ proxy_cache.c 1998/06/02 12:50:46 1.42
@@ -71,33 +71,37 @@
DEF_Explain
-#ifndef abs
-#define abs(c) ((c) >= 0 ? (c) : -(c))
-#endif
-
struct gc_ent {
unsigned long int len;
time_t expire;
char file[HASH_LEN + 1];
-
};
-
-static int gcdiff(const void *ap, const void *bp)
-{
- const struct gc_ent *a = *(const struct gc_ent * const *) ap;
- const struct gc_ent *b = *(const struct gc_ent * const *) bp;
-
- if (a->expire > b->expire)
- return 1;
- else if (a->expire < b->expire)
- return -1;
- else
- return 0;
-}
-static int curbytes, cachesize, every;
-static unsigned long int curblocks;
-static time_t garbage_now, garbage_expire;
+/* Poor man's 61 bit arithmetic */
+typedef struct {
+ long lower; /* lower 30 bits of result */
+ long upper; /* upper 31 bits of result */
+} long61_t;
+
+/* FIXME: The block size can be different on a `per file system' base.
+ * This would make automatic detection highly OS specific.
+ * In the GNU fileutils code for du(1), you can see how complicated it can
+ * become to detect the block size. And, with BSD-4.x fragments, it
+ * it even more difficult to get precise results.
+ * As a compromise (and to improve on the incorrect counting of cache
+ * size on byte level, omitting directory sizes entirely, which was
+ * used up to apache-1.3b7) we're rounding to multiples of 512 here.
+ * Your file system may be using larger blocks (I certainly hope so!)
+ * but it will hardly use smaller blocks.
+ * (So this approximation is still closer to reality than the old behavior).
+ * The best solution would be automatic detection, the next best solution
+ * IMHO is a sensible default and the possibility to override it.
+ */
+
+#define ROUNDUP2BLOCKS(_bytes) (((_bytes)+block_size-1) & ~(block_size-1))
+static long block_size = 512; /* this must be a power of 2 */
+static long61_t curbytes, cachesize;
+static time_t every, garbage_now, garbage_expire;
static char *filename;
static mutex *garbage_mutex = NULL;
@@ -114,6 +118,10 @@
static int sub_garbage_coll(request_rec *r, array_header *files,
const char *cachedir, const char *cachesubdir);
static void help_proxy_garbage_coll(request_rec *r);
+#if !defined(WIN32) && !defined(MPE) && !defined(__EMX__)
+static void detached_proxy_garbage_coll(request_rec *r);
+#endif
+
void ap_proxy_garbage_coll(request_rec *r)
{
@@ -128,7 +136,13 @@
inside = 1;
(void) ap_release_mutex(garbage_mutex);
+ ap_block_alarms(); /* avoid SIGALRM on big cache cleanup */
+#if !defined(WIN32) && !defined(MPE) && !defined(__EMX__)
+ detached_proxy_garbage_coll(r);
+#else
help_proxy_garbage_coll(r);
+#endif
+ ap_unblock_alarms();
(void) ap_acquire_mutex(garbage_mutex);
inside = 0;
@@ -136,6 +150,116 @@
}
+static void
+add_long61 (long61_t *accu, long val)
+{
+ /* Add in lower 30 bits */
+ accu->lower += (val & 0x3FFFFFFFL);
+ /* add in upper bits, and carry */
+ accu->upper += (val >> 30) + ((accu->lower & ~0x3FFFFFFFL) != 0L);
+ /* Clear carry */
+ accu->lower &= 0x3FFFFFFFL;
+}
+
+static void
+sub_long61 (long61_t *accu, long val)
+{
+ int carry = (val & 0x3FFFFFFFL) > accu->lower;
+ /* Subtract lower 30 bits */
+ accu->lower = accu->lower - (val & 0x3FFFFFFFL) + ((carry) ? 0x40000000
: 0);
+ /* add in upper bits, and carry */
+ accu->upper -= (val >> 30) + carry;
+}
+
+/* Compare two long61's:
+ * return <0 when left < right
+ * return 0 when left == right
+ * return >0 when left > right
+ */
+static long
+cmp_long61 (long61_t *left, long61_t *right)
+{
+ return (left->upper == right->upper) ? (left->lower - right->lower)
+ : (left->upper - right->upper);
+}
+
+/* Compare two gc_ent's, sort them by expiration date */
+static int gcdiff(const void *ap, const void *bp)
+{
+ const struct gc_ent *a = (const struct gc_ent * const) ap;
+ const struct gc_ent *b = (const struct gc_ent * const) bp;
+
+ if (a->expire > b->expire)
+ return 1;
+ else if (a->expire < b->expire)
+ return -1;
+ else
+ return 0;
+}
+
+#if !defined(WIN32) && !defined(MPE) && !defined(__EMX__)
+static void detached_proxy_garbage_coll(request_rec *r)
+{
+ pid_t pid;
+ int status;
+ pid_t pgrp;
+
+ switch (pid = fork()) {
+ case -1:
+ ap_log_error(APLOG_MARK, APLOG_ERR, r->server,
+ "proxy: fork() for cache cleanup failed");
+ return;
+
+ case 0: /* Child */
+
+ /* close all sorts of things, including the socket fd */
+ ap_cleanup_for_exec();
+
+ /* Fork twice to disassociate from the child */
+ switch (pid = fork()) {
+ case -1:
+ ap_log_error(APLOG_MARK, APLOG_ERR, r->server,
+ "proxy: fork(2nd) for cache cleanup failed");
+ exit(1);
+
+ case 0: /* Child */
+ /* The setpgrp() stuff was snarfed from http_main.c */
+#ifndef NO_SETSID
+ if ((pgrp = setsid()) == -1) {
+ perror("setsid");
+ fprintf(stderr, "httpd: setsid failed\n");
+ exit(1);
+ }
+#elif defined(NEXT) || defined(NEWSOS)
+ if (setpgrp(0, getpid()) == -1 || (pgrp = getpgrp(0)) ==
-1) {
+ perror("setpgrp");
+ fprintf(stderr, "httpd: setpgrp or getpgrp failed\n");
+ exit(1);
+ }
+#else
+ if ((pgrp = setpgrp(getpid(), 0)) == -1) {
+ perror("setpgrp");
+ fprintf(stderr, "httpd: setpgrp failed\n");
+ exit(1);
+ }
+#endif
+ help_proxy_garbage_coll(r);
+ exit(0);
+
+ default: /* Father */
+ /* After grandson has been forked off, */
+ /* there's nothing else to do. */
+ exit(0);
+ }
+ default:
+ /* Wait until grandson has been forked off */
+ /* (without wait we'd leave a zombie) */
+ waitpid(pid, &status, 0);
+ return;
+ }
+}
+#endif /* ndef WIN32 */
+
static void help_proxy_garbage_coll(request_rec *r)
{
const char *cachedir;
@@ -145,17 +269,24 @@
const struct cache_conf *conf = &pconf->cache;
array_header *files;
struct stat buf;
- struct gc_ent *fent, **elts;
+ struct gc_ent *fent;
int i, timefd;
- static time_t lastcheck = BAD_DATE; /* static data!!! */
+ static time_t lastcheck = BAD_DATE; /* static (per-process)
data!!! */
cachedir = conf->root;
- cachesize = conf->space;
+ /* configured size is given in kB. Make it bytes, convert to long61_t: */
+ cachesize.lower = cachesize.upper = 0;
+ add_long61(&cachesize, conf->space << 10);
every = conf->gcinterval;
if (cachedir == NULL || every == -1)
return;
garbage_now = time(NULL);
+ /* Usually, the modification time of <cachedir>/.time can only increase.
+ * Thus, even with several child processes having their own copy of
+ * lastcheck, if time(NULL) still < lastcheck then it's not time
+ * for GC yet.
+ */
if (garbage_now != -1 && lastcheck != BAD_DATE && garbage_now <
lastcheck + every)
return;
@@ -176,7 +307,7 @@
ap_log_error(APLOG_MARK, APLOG_ERR, r->server,
"proxy: creat(%s)", filename);
else
- lastcheck = abs(garbage_now); /* someone else got in there */
+ lastcheck = garbage_now; /* someone else got in there */
ap_unblock_alarms();
return;
}
@@ -192,22 +323,24 @@
ap_log_error(APLOG_MARK, APLOG_ERR, r->server,
"proxy: utimes(%s)", filename);
}
- files = ap_make_array(r->pool, 100, sizeof(struct gc_ent *));
- curblocks = 0;
- curbytes = 0;
+ files = ap_make_array(r->pool, 100, sizeof(struct gc_ent));
+ curbytes.upper = curbytes.lower = 0L;
sub_garbage_coll(r, files, cachedir, "/");
- if (curblocks < cachesize || curblocks + curbytes <= cachesize) {
+ if (cmp_long61(&curbytes, &cachesize) < 0L) {
+ ap_log_error(APLOG_MARK, APLOG_DEBUG|APLOG_NOERRNO, r->server,
+ "proxy GC: Cache is %ld%% full (nothing deleted)",
+
((curbytes.upper<<20)|(curbytes.lower>>10))*100/conf->space);
ap_unblock_alarms();
return;
}
- qsort(files->elts, files->nelts, sizeof(struct gc_ent *), gcdiff);
+ /* sort the files we found by expiration date */
+ qsort(files->elts, files->nelts, sizeof(struct gc_ent), gcdiff);
- elts = (struct gc_ent **) files->elts;
for (i = 0; i < files->nelts; i++) {
- fent = elts[i];
+ fent = &((struct gc_ent *) files->elts)[i];
sprintf(filename, "%s%s", cachedir, fent->file);
Explain3("GC Unlinking %s (expiry %ld, garbage_now %ld)", filename,
fent->expire, garbage_now);
#if TESTING
@@ -221,16 +354,15 @@
else
#endif
{
- curblocks -= fent->len >> 10;
- curbytes -= fent->len & 0x3FF;
- if (curbytes < 0) {
- curbytes += 1024;
- curblocks--;
- }
- if (curblocks < cachesize || curblocks + curbytes <= cachesize)
+ sub_long61(&curbytes, ROUNDUP2BLOCKS(fent->len));
+ if (cmp_long61(&curbytes, &cachesize) < 0)
break;
}
}
+
+ ap_log_error(APLOG_MARK, APLOG_DEBUG|APLOG_NOERRNO, r->server,
+ "proxy GC: Cache is %ld%% full (%d deleted)",
+
((curbytes.upper<<20)|(curbytes.lower>>10))*100/conf->space, i);
ap_unblock_alarms();
}
@@ -342,6 +474,9 @@
rmdir(newcachedir);
#endif
--nfiles;
+ } else {
+ /* Directory is not empty. Account for its size: */
+ add_long61(&curbytes, ROUNDUP2BLOCKS(buf.st_size));
}
continue;
}
@@ -378,22 +513,14 @@
* file.
*
*/
- /* FIXME: We should make the array an array of gc_ents, not gc_ent *s
- */
- fent = ap_palloc(r->pool, sizeof(struct gc_ent));
+ fent = (struct gc_ent *) ap_push_array(files);
fent->len = buf.st_size;
fent->expire = garbage_expire;
strcpy(fent->file, cachesubdir);
strcat(fent->file, ent->d_name);
- *(struct gc_ent **) ap_push_array(files) = fent;
/* accumulate in blocks, to cope with directories > 4Gb */
- curblocks += buf.st_size >> 10; /* Kbytes */
- curbytes += buf.st_size & 0x3FF;
- if (curbytes >= 1024) {
- curbytes -= 1024;
- curblocks++;
- }
+ add_long61(&curbytes, ROUNDUP2BLOCKS(buf.st_size));
}
closedir(dir);
@@ -467,7 +594,7 @@
q = ap_proxy_get_header(c->hdrs, "Content-Length");
if (q == NULL) {
strp = ap_palloc(p, 15);
- ap_snprintf(strp, 15, "%u", c->len);
+ ap_snprintf(strp, 15, "%lu", c->len);
ap_proxy_add_header(c->hdrs, "Content-Length", strp, HDR_REP);
}
}
@@ -590,7 +717,7 @@
}
ap_pclosef(r->pool, cachefp->fd);
Explain0("Use local copy, cached file hasn't changed");
- return USE_LOCAL_COPY;
+ return HTTP_NOT_MODIFIED;
}
/* Ok, has been modified */
@@ -735,7 +862,7 @@
/* no date header! */
/* add one; N.B. use the time _now_ rather than when we were checking the
cache
*/
- date = abs(now);
+ date = now;
p = ap_gm_timestr_822(r->pool, now);
dates = ap_proxy_add_header(resp_hdrs, "Date", p, HDR_REP);
Explain0("Added date header");
@@ -775,10 +902,10 @@
double maxex = conf->cache.maxexpire;
if (x > maxex)
x = maxex;
- expc = abs(now) + (int) x;
+ expc = now + (int) x;
}
else
- expc = abs(now) + conf->cache.defaultexpire;
+ expc = now + conf->cache.defaultexpire;
Explain1("Expiry date calculated %ld", expc);
}
@@ -820,7 +947,7 @@
ap_pclosef(r->pool, c->fp->fd);
Explain0("Remote document not modified, use local copy");
/* CHECKME: Is this right? Shouldn't we check IMS again here? */
- return USE_LOCAL_COPY;
+ return HTTP_NOT_MODIFIED;
}
else {
/* return the whole document */
