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