path: root/Documentation
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authorLinus Torvalds <>2015-11-10 12:07:22 -0800
committerLinus Torvalds <>2015-11-10 12:07:22 -0800
commit264015f8a83fefc62c5125d761fbbadf924e520c (patch)
tree6a0602761abb3d866471861a7128a5177a855fd0 /Documentation
parentd55fc37856244c929965c190c8e9dcb49e2c07aa (diff)
parentab27a8d04b32b6ee8c30c14c4afd1058e8addc82 (diff)
Merge tag 'libnvdimm-for-4.4' of git://
Pull libnvdimm updates from Dan Williams: "Outside of the new ACPI-NFIT hot-add support this pull request is more notable for what it does not contain, than what it does. There were a handful of development topics this cycle, dax get_user_pages, dax fsync, and raw block dax, that need more more iteration and will wait for 4.5. The patches to make devm and the pmem driver NUMA aware have been in -next for several weeks. The hot-add support has not, but is contained to the NFIT driver and is passing unit tests. The coredump support is straightforward and was looked over by Jeff. All of it has received a 0day build success notification across 107 configs. Summary: - Add support for the ACPI 6.0 NFIT hot add mechanism to process updates of the NFIT at runtime. - Teach the coredump implementation how to filter out DAX mappings. - Introduce NUMA hints for allocations made by the pmem driver, and as a side effect all devm allocations now hint their NUMA node by default" * tag 'libnvdimm-for-4.4' of git:// coredump: add DAX filtering for FDPIC ELF coredumps coredump: add DAX filtering for ELF coredumps acpi: nfit: Add support for hot-add nfit: in acpi_nfit_init, break on a 0-length table pmem, memremap: convert to numa aware allocations devm_memremap_pages: use numa_mem_id devm: make allocations numa aware by default devm_memremap: convert to return ERR_PTR devm_memunmap: use devres_release() pmem: kill memremap_pmem() x86, mm: quiet arch_add_memory()
Diffstat (limited to 'Documentation')
1 files changed, 12 insertions, 10 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 1e4a6cc1b6ea..402ab99e409f 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -1605,16 +1605,16 @@ Documentation/accounting.
When a process is dumped, all anonymous memory is written to a core file as
long as the size of the core file isn't limited. But sometimes we don't want
-to dump some memory segments, for example, huge shared memory. Conversely,
-sometimes we want to save file-backed memory segments into a core file, not
-only the individual files.
+to dump some memory segments, for example, huge shared memory or DAX.
+Conversely, sometimes we want to save file-backed memory segments into a core
+file, not only the individual files.
/proc/<pid>/coredump_filter allows you to customize which memory segments
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 7 memory types are supported:
+The following 9 memory types are supported:
- (bit 0) anonymous private memory
- (bit 1) anonymous shared memory
- (bit 2) file-backed private memory
@@ -1623,20 +1623,22 @@ The following 7 memory types are supported:
effective only if the bit 2 is cleared)
- (bit 5) hugetlb private memory
- (bit 6) hugetlb shared memory
+ - (bit 7) DAX private memory
+ - (bit 8) DAX shared memory
Note that MMIO pages such as frame buffer are never dumped and vDSO pages
are always dumped regardless of the bitmask status.
- Note bit 0-4 doesn't effect any hugetlb memory. hugetlb memory are only
- effected by bit 5-6.
+ Note that bits 0-4 don't affect hugetlb or DAX memory. hugetlb memory is
+ only affected by bit 5-6, and DAX is only affected by bits 7-8.
-Default value of coredump_filter is 0x23; this means all anonymous memory
-segments and hugetlb private memory are dumped.
+The default value of coredump_filter is 0x33; this means all anonymous memory
+segments, ELF header pages and hugetlb private memory are dumped.
If you don't want to dump all shared memory segments attached to pid 1234,
-write 0x21 to the process's proc file.
+write 0x31 to the process's proc file.
- $ echo 0x21 > /proc/1234/coredump_filter
+ $ echo 0x31 > /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.