Work around unintelligent kernel OOM-kill algorithm.postgresql-8_4_2-4_fc13

1 files changed, 57 insertions, 0 deletions

diff --git a/postgresql-oom-adj.patch b/postgresql-oom-adj.patch
new file mode 100644
index 0000000..4ac05e6
--- /dev/null
+++ b/postgresql-oom-adj.patch
@@ -0,0 +1,57 @@
+Back-ported patch from Postgres devel head: reset oom_adj to zero in any
+postmaster child process.  This allows us to disable OOM kill on the postmaster
+(see the init script) without affecting OOM behavior for child processes.
+
+
+diff -Naur postgresql-8.4.2.orig/src/backend/postmaster/fork_process.c postgresql-8.4.2/src/backend/postmaster/fork_process.c
+--- postgresql-8.4.2.orig/src/backend/postmaster/fork_process.c	2009-01-01 12:23:46.000000000 -0500
++++ postgresql-8.4.2/src/backend/postmaster/fork_process.c	2010-01-11 12:28:17.000000000 -0500
+@@ -12,7 +12,9 @@
+ #include "postgres.h"
+ #include "postmaster/fork_process.h"
+ 
++#include <fcntl.h>
+ #include <time.h>
++#include <sys/stat.h>
+ #include <sys/time.h>
+ #include <unistd.h>
+ 
+@@ -60,6 +62,38 @@
+ 		setitimer(ITIMER_PROF, &prof_itimer, NULL);
+ #endif
+ 
++		/*
++		 * By default, Linux tends to kill the postmaster in out-of-memory
++		 * situations, because it blames the postmaster for the sum of child
++		 * process sizes *including shared memory*.  (This is unbelievably
++		 * stupid, but the kernel hackers seem uninterested in improving it.)
++		 * Therefore it's often a good idea to protect the postmaster by
++		 * setting its oom_adj value negative (which has to be done in a
++		 * root-owned startup script).  If you just do that much, all child
++		 * processes will also be protected against OOM kill, which might not
++		 * be desirable.  You can then choose to build with LINUX_OOM_ADJ
++		 * #defined to 0, or some other value that you want child processes
++		 * to adopt here.
++		 */
++#ifdef LINUX_OOM_ADJ
++		{
++			/*
++			 * Use open() not stdio, to ensure we control the open flags.
++			 * Some Linux security environments reject anything but O_WRONLY.
++			 */
++			int		fd = open("/proc/self/oom_adj", O_WRONLY, 0);
++
++			/* We ignore all errors */
++			if (fd >= 0)
++			{
++				char	buf[16];
++
++				snprintf(buf, sizeof(buf), "%d\n", LINUX_OOM_ADJ);
++				(void) write(fd, buf, strlen(buf));
++				close(fd);
++			}
++		}
++#endif /* LINUX_OOM_ADJ */
+ 	}
+ 
+ 	return result;