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-rw-r--r--Documentation/filesystems/proc.txt15
1 files changed, 10 insertions, 5 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index c032bf39e8b9..02cb7faeed6b 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -2412,24 +2412,29 @@ will be dumped when the <pid> process is dumped. coredump_filter is a bitmask
of memory types. If a bit of the bitmask is set, memory segments of the
corresponding memory type are dumped, otherwise they are not dumped.
-The following 4 memory types are supported:
+The following 7 memory types are supported:
- (bit 0) anonymous private memory
- (bit 1) anonymous shared memory
- (bit 2) file-backed private memory
- (bit 3) file-backed shared memory
- (bit 4) ELF header pages in file-backed private memory areas (it is
effective only if the bit 2 is cleared)
+ - (bit 5) hugetlb private memory
+ - (bit 6) hugetlb shared memory
Note that MMIO pages such as frame buffer are never dumped and vDSO pages
are always dumped regardless of the bitmask status.
-Default value of coredump_filter is 0x3; this means all anonymous memory
-segments are dumped.
+ Note bit 0-4 doesn't effect any hugetlb memory. hugetlb memory are only
+ effected by bit 5-6.
+
+Default value of coredump_filter is 0x23; this means all anonymous memory
+segments and hugetlb private memory are dumped.
If you don't want to dump all shared memory segments attached to pid 1234,
-write 1 to the process's proc file.
+write 0x21 to the process's proc file.
- $ echo 0x1 > /proc/1234/coredump_filter
+ $ echo 0x21 > /proc/1234/coredump_filter
When a new process is created, the process inherits the bitmask status from its
parent. It is useful to set up coredump_filter before the program runs.