Allocate Backend structs in PostmasterContext.

The child processes don't need them. By allocating them in
PostmasterContext, the memory gets free'd and is made available for
other stuff in the child processes.

Reviewed-by: Thomas Munro
Discussion: https://www.postgresql.org/message-id/4f95c1fc-ad3c-7974-3a8c-6faa3931804c@iki.fi

diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 31350d64013cf07065e55f61bf5fb86dc50e24b5..cc66c61dee792c52d2482a927c1f52b2274670f8 100644 (file)
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -33,6 +33,7 @@
 #include "storage/shmem.h"
 #include "tcop/tcopprot.h"
 #include "utils/ascii.h"
+#include "utils/memutils.h"
 #include "utils/ps_status.h"
 #include "utils/timeout.h"
 
@@ -347,7 +348,9 @@ BackgroundWorkerStateChange(bool allow_new_workers)
        /*
         * Copy the registration data into the registered workers list.
         */
-       rw = malloc(sizeof(RegisteredBgWorker));
+       rw = MemoryContextAllocExtended(PostmasterContext,
+                                       sizeof(RegisteredBgWorker),
+                                       MCXT_ALLOC_NO_OOM);
        if (rw == NULL)
        {
            ereport(LOG,
@@ -455,7 +458,7 @@ ForgetBackgroundWorker(slist_mutable_iter *cur)
                             rw->rw_worker.bgw_name)));
 
    slist_delete_current(cur);
-   free(rw);
+   pfree(rw);
 }
 
 /*
@@ -951,7 +954,9 @@ RegisterBackgroundWorker(BackgroundWorker *worker)
    /*
     * Copy the registration data into the registered workers list.
     */
-   rw = malloc(sizeof(RegisteredBgWorker));
+   rw = MemoryContextAllocExtended(PostmasterContext,
+                                   sizeof(RegisteredBgWorker),
+                                   MCXT_ALLOC_NO_OOM);
    if (rw == NULL)
    {
        ereport(LOG,

diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index bc3c992a3a3c443876b1052dccfd3ee327323e79..583c9b03246352dd5515848a865c28a70550088b 100644 (file)
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -3321,7 +3321,7 @@ CleanupBackgroundWorker(int pid,
         */
        if (rw->rw_backend->bgworker_notify)
            BackgroundWorkerStopNotifications(rw->rw_pid);
-       free(rw->rw_backend);
+       pfree(rw->rw_backend);
        rw->rw_backend = NULL;
        rw->rw_pid = 0;
        rw->rw_child_slot = 0;
@@ -3414,7 +3414,7 @@ CleanupBackend(int pid,
                BackgroundWorkerStopNotifications(bp->pid);
            }
            dlist_delete(iter.cur);
-           free(bp);
+           pfree(bp);
            break;
        }
    }
@@ -3470,7 +3470,7 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 #ifdef EXEC_BACKEND
            ShmemBackendArrayRemove(rw->rw_backend);
 #endif
-           free(rw->rw_backend);
+           pfree(rw->rw_backend);
            rw->rw_backend = NULL;
            rw->rw_pid = 0;
            rw->rw_child_slot = 0;
@@ -3507,7 +3507,7 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 #endif
            }
            dlist_delete(iter.cur);
-           free(bp);
+           pfree(bp);
            /* Keep looping so we can signal remaining backends */
        }
        else
@@ -4083,7 +4083,7 @@ BackendStartup(Port *port)
     * Create backend data structure.  Better before the fork() so we can
     * handle failure cleanly.
     */
-   bn = (Backend *) malloc(sizeof(Backend));
+   bn = (Backend *) palloc_extended(sizeof(Backend), MCXT_ALLOC_NO_OOM);
    if (!bn)
    {
        ereport(LOG,
@@ -4099,7 +4099,7 @@ BackendStartup(Port *port)
     */
    if (!RandomCancelKey(&MyCancelKey))
    {
-       free(bn);
+       pfree(bn);
        ereport(LOG,
                (errcode(ERRCODE_INTERNAL_ERROR),
                 errmsg("could not generate random cancel key")));
@@ -4129,8 +4129,6 @@ BackendStartup(Port *port)
    pid = fork_process();
    if (pid == 0)               /* child */
    {
-       free(bn);
-
        /* Detangle from postmaster */
        InitPostmasterChild();
 
@@ -4161,7 +4159,7 @@ BackendStartup(Port *port)
 
        if (!bn->dead_end)
            (void) ReleasePostmasterChildSlot(bn->child_slot);
-       free(bn);
+       pfree(bn);
        errno = save_errno;
        ereport(LOG,
                (errmsg("could not fork new process for connection: %m")));
@@ -5424,7 +5422,7 @@ StartAutovacuumWorker(void)
            return;
        }
 
-       bn = (Backend *) malloc(sizeof(Backend));
+       bn = (Backend *) palloc_extended(sizeof(Backend), MCXT_ALLOC_NO_OOM);
        if (bn)
        {
            bn->cancel_key = MyCancelKey;
@@ -5451,7 +5449,7 @@ StartAutovacuumWorker(void)
             * logged by StartAutoVacWorker
             */
            (void) ReleasePostmasterChildSlot(bn->child_slot);
-           free(bn);
+           pfree(bn);
        }
        else
            ereport(LOG,
@@ -5696,7 +5694,7 @@ do_start_bgworker(RegisteredBgWorker *rw)
            /* undo what assign_backendlist_entry did */
            ReleasePostmasterChildSlot(rw->rw_child_slot);
            rw->rw_child_slot = 0;
-           free(rw->rw_backend);
+           pfree(rw->rw_backend);
            rw->rw_backend = NULL;
            /* mark entry as crashed, so we'll try again later */
            rw->rw_crashed_at = GetCurrentTimestamp();
@@ -5822,7 +5820,7 @@ assign_backendlist_entry(RegisteredBgWorker *rw)
        return false;
    }
 
-   bn = malloc(sizeof(Backend));
+   bn = palloc_extended(sizeof(Backend), MCXT_ALLOC_NO_OOM);
    if (bn == NULL)
    {
        ereport(LOG,