Patch by Duane:

Dynamically calculate the amount of needed SHM buffers for diskd at startup,
and complain if squid -k reconfigure tries to increase the Q1/Q2 values.

diff --git a/src/fs/diskd/store_dir_diskd.cc b/src/fs/diskd/store_dir_diskd.cc
index cf6c1b9147c5624611810ee88f60ee92e0649def..a21b131124229bba2bafad46b18709dd35ac30ba 100644 (file)
--- a/src/fs/diskd/store_dir_diskd.cc
+++ b/src/fs/diskd/store_dir_diskd.cc
@@ -1,6 +1,6 @@
 
 /*
- * $Id: store_dir_diskd.cc,v 1.62 2002/04/06 08:49:43 adrian Exp $
+ * $Id: store_dir_diskd.cc,v 1.63 2002/04/06 12:54:42 hno Exp $
  *
  * DEBUG: section 47    Store Directory Routines
  * AUTHOR: Duane Wessels
@@ -385,8 +385,9 @@ storeDiskdDirInit(SwapDir * sd)
        debug(50, 0) ("storeDiskdInit: msgget: %s\n", xstrerror());
        fatal("msgget failed");
     }
+    diskdinfo->shm.nbufs = diskdinfo->magic2 * 1.3;
     diskdinfo->shm.id = shmget((key_t) (ikey + 2),
-       SHMBUFS * SHMBUF_BLKSZ, 0600 | IPC_CREAT);
+       diskdinfo->shm.nbufs * SHMBUF_BLKSZ, 0600 | IPC_CREAT);
     if (diskdinfo->shm.id < 0) {
        debug(50, 0) ("storeDiskdInit: shmget: %s\n", xstrerror());
        fatal("shmget failed");
@@ -396,9 +397,9 @@ storeDiskdDirInit(SwapDir * sd)
        debug(50, 0) ("storeDiskdInit: shmat: %s\n", xstrerror());
        fatal("shmat failed");
     }
-    diskdinfo->shm.inuse_map = xcalloc((SHMBUFS + 7) / 8, 1);
-    diskd_stats.shmbuf_count += SHMBUFS;
-    for (i = 0; i < SHMBUFS; i++) {
+    diskdinfo->shm.inuse_map = xcalloc((diskdinfo->shm.nbufs + 7) / 8, 1);
+    diskd_stats.shmbuf_count += diskdinfo->shm.nbufs;
+    for (i = 0; i < diskdinfo->shm.nbufs; i++) {
        CBIT_SET(diskdinfo->shm.inuse_map, i);
        storeDiskdShmPut(sd, i * SHMBUF_BLKSZ);
     }
@@ -1632,7 +1633,7 @@ storeDiskdShmGet(SwapDir * sd, off_t * shm_offset)
     char *buf = NULL;
     diskdinfo_t *diskdinfo = sd->fsdata;
     int i;
-    for (i = 0; i < SHMBUFS; i++) {
+    for (i = 0; i < diskdinfo->shm.nbufs; i++) {
        if (CBIT_TEST(diskdinfo->shm.inuse_map, i))
            continue;
        CBIT_SET(diskdinfo->shm.inuse_map, i);
@@ -1642,7 +1643,7 @@ storeDiskdShmGet(SwapDir * sd, off_t * shm_offset)
     }
     assert(buf);
     assert(buf >= diskdinfo->shm.buf);
-    assert(buf < diskdinfo->shm.buf + (SHMBUFS * SHMBUF_BLKSZ));
+    assert(buf < diskdinfo->shm.buf + (diskdinfo->shm.nbufs * SHMBUF_BLKSZ));
     diskd_stats.shmbuf_count++;
     if (diskd_stats.max_shmuse < diskd_stats.shmbuf_count)
        diskd_stats.max_shmuse = diskd_stats.shmbuf_count;
@@ -1655,9 +1656,9 @@ storeDiskdShmPut(SwapDir * sd, off_t offset)
     int i;
     diskdinfo_t *diskdinfo = sd->fsdata;
     assert(offset >= 0);
-    assert(offset < SHMBUFS * SHMBUF_BLKSZ);
+    assert(offset < diskdinfo->shm.nbufs * SHMBUF_BLKSZ);
     i = offset / SHMBUF_BLKSZ;
-    assert(i < SHMBUFS);
+    assert(i < diskdinfo->shm.nbufs);
     assert(CBIT_TEST(diskdinfo->shm.inuse_map, i));
     CBIT_CLR(diskdinfo->shm.inuse_map, i);
     diskd_stats.shmbuf_count--;
@@ -1712,7 +1713,21 @@ storeDiskdDirParseQ1(SwapDir * sd, const char *name, const char *value, int reco
     diskdinfo_t *diskdinfo = sd->fsdata;
     int old_magic1 = diskdinfo->magic1;
     diskdinfo->magic1 = atoi(value);
-    if (reconfiguring && old_magic1 != diskdinfo->magic1)
+    if (!reconfiguring)
+       return;
+    if (old_magic1 < diskdinfo->magic1) {
+       /*
+       * This is because shm.nbufs is computed at startup, when
+       * we call shmget().  We can't increase the Q1/Q2 parameters
+       * beyond their initial values because then we might have
+       * more "Q2 messages" than shared memory chunks, and this
+       * will cause an assertion in storeDiskdShmGet().
+       */
+       debug(3, 1) ("WARNING: cannot increase cache_dir '%s' Q1 value while Squid is running.\n", sd->path);
+       diskdinfo->magic1 = old_magic1;
+       return;
+    }
+    if (old_magic1 != diskdinfo->magic1)
        debug(3, 1) ("cache_dir '%s' new Q1 value '%d'\n",
            sd->path, diskdinfo->magic1);
 }
@@ -1730,7 +1745,15 @@ storeDiskdDirParseQ2(SwapDir * sd, const char *name, const char *value, int reco
     diskdinfo_t *diskdinfo = sd->fsdata;
     int old_magic2 = diskdinfo->magic2;
     diskdinfo->magic2 = atoi(value);
-    if (reconfiguring && old_magic2 != diskdinfo->magic2)
+    if (!reconfiguring)
+       return;
+    if (old_magic2 < diskdinfo->magic2) {
+       /* See comments in Q1 function above */
+       debug(3, 1) ("WARNING: cannot increase cache_dir '%s' Q2 value while Squid is running.\n", sd->path);
+       diskdinfo->magic2 = old_magic2;
+       return;
+    }
+    if (old_magic2 != diskdinfo->magic2)
        debug(3, 1) ("cache_dir '%s' new Q2 value '%d'\n",
            sd->path, diskdinfo->magic2);
 }

diff --git a/src/fs/diskd/store_diskd.h b/src/fs/diskd/store_diskd.h
index 8470cb84d982fba516c1ca46a817c7db3522d136..1a955b76ef640077b971864944a6836a7d11119c 100644 (file)
--- a/src/fs/diskd/store_diskd.h
+++ b/src/fs/diskd/store_diskd.h
@@ -29,6 +29,7 @@ struct _diskdinfo_t {
        char *buf;
        char *inuse_map;
        int id;
+       int nbufs;
     } shm;
     int magic1;
     int magic2;
@@ -111,11 +112,6 @@ extern STOBJREAD storeDiskdRead;
 extern STOBJWRITE storeDiskdWrite;
 extern STOBJUNLINK storeDiskdUnlink;
 
-/*
- * SHMBUFS is the number of shared memory buffers to allocate for
- * Each SwapDir.
- */
-#define SHMBUFS 96
 #define SHMBUF_BLKSZ SM_PAGE_SIZE
 
 extern diskd_stats_t diskd_stats;