diff options
Diffstat (limited to 'sys/kern/kern_descrip.c')
| -rw-r--r-- | sys/kern/kern_descrip.c | 32 |
1 files changed, 21 insertions, 11 deletions
diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c index 908de94..7fb39cc 100644 --- a/sys/kern/kern_descrip.c +++ b/sys/kern/kern_descrip.c @@ -1522,7 +1522,7 @@ fdgrowtable(struct filedesc *fdp, int nfd) return; /* - * Allocate a new table and map. We need enough space for the + * Allocate a new table. We need enough space for the * file entries themselves and the struct freetable we will use * when we decommission the table and place it on the freelist. * We place the struct freetable in the middle so we don't have @@ -1530,16 +1530,22 @@ fdgrowtable(struct filedesc *fdp, int nfd) */ ntable = malloc(nnfiles * sizeof(ntable[0]) + sizeof(struct freetable), M_FILEDESC, M_ZERO | M_WAITOK); - nmap = malloc(NDSLOTS(nnfiles) * NDSLOTSIZE, M_FILEDESC, - M_ZERO | M_WAITOK); - /* copy the old data over and point at the new tables */ memcpy(ntable, otable, onfiles * sizeof(*otable)); - memcpy(nmap, omap, NDSLOTS(onfiles) * sizeof(*omap)); - - /* update the pointers and counters */ fdp->fd_ofiles = ntable; - fdp->fd_map = nmap; + + /* + * Allocate a new map only if the old is not large enough. It will + * grow at a slower rate than the table as it can map more + * entries than the table can hold. + */ + if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) { + nmap = malloc(NDSLOTS(nnfiles) * NDSLOTSIZE, M_FILEDESC, + M_ZERO | M_WAITOK); + /* copy over the old data and update the pointer */ + memcpy(nmap, omap, NDSLOTS(onfiles) * sizeof(*omap)); + fdp->fd_map = nmap; + } /* * In order to have a valid pattern for fget_unlocked() @@ -1555,8 +1561,6 @@ fdgrowtable(struct filedesc *fdp, int nfd) * reference entries within it. Instead, place it on a freelist * which will be processed when the struct filedesc is released. * - * Do, however, free the old map. - * * Note that if onfiles == NDFILE, we're dealing with the original * static allocation contained within (struct filedesc0 *)fdp, * which must not be freed. @@ -1566,8 +1570,14 @@ fdgrowtable(struct filedesc *fdp, int nfd) fdp0 = (struct filedesc0 *)fdp; ft->ft_table = otable; SLIST_INSERT_HEAD(&fdp0->fd_free, ft, ft_next); - free(omap, M_FILEDESC); } + /* + * The map does not have the same possibility of threads still + * holding references to it. So always free it as long as it + * does not reference the original static allocation. + */ + if (NDSLOTS(onfiles) > NDSLOTS(NDFILE)) + free(omap, M_FILEDESC); } /* |
