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authorStephen Kitt <steve@sk2.org>2020-06-23 14:25:14 +0300
committerJonathan Corbet <corbet@lwn.net>2020-06-26 20:25:14 +0300
commit0b227076d509c2facf177d7cdb67cbbb885cb661 (patch)
treeff71a6c8914edcd895c8abd8205cdaf93acd1177 /Documentation/admin-guide/sysctl
parent48d4b96c08b6cb03178d0509e6d7ba121730fb95 (diff)
downloadlinux-0b227076d509c2facf177d7cdb67cbbb885cb661.tar.xz
docs: sysctl/kernel: document random
This documents the random directory, based on the behaviour seen in drivers/char/random.c. Signed-off-by: Stephen Kitt <steve@sk2.org> Link: https://lore.kernel.org/r/20200623112514.10650-1-steve@sk2.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/admin-guide/sysctl')
-rw-r--r--Documentation/admin-guide/sysctl/kernel.rst32
1 files changed, 32 insertions, 0 deletions
diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
index 6d96f17b74a4..5f432f51f23e 100644
--- a/Documentation/admin-guide/sysctl/kernel.rst
+++ b/Documentation/admin-guide/sysctl/kernel.rst
@@ -996,6 +996,38 @@ pty
See Documentation/filesystems/devpts.rst.
+random
+======
+
+This is a directory, with the following entries:
+
+* ``boot_id``: a UUID generated the first time this is retrieved, and
+ unvarying after that;
+
+* ``entropy_avail``: the pool's entropy count, in bits;
+
+* ``poolsize``: the entropy pool size, in bits;
+
+* ``urandom_min_reseed_secs``: obsolete (used to determine the minimum
+ number of seconds between urandom pool reseeding).
+
+* ``uuid``: a UUID generated every time this is retrieved (this can
+ thus be used to generate UUIDs at will);
+
+* ``write_wakeup_threshold``: when the entropy count drops below this
+ (as a number of bits), processes waiting to write to ``/dev/random``
+ are woken up.
+
+If ``drivers/char/random.c`` is built with ``ADD_INTERRUPT_BENCH``
+defined, these additional entries are present:
+
+* ``add_interrupt_avg_cycles``: the average number of cycles between
+ interrupts used to feed the pool;
+
+* ``add_interrupt_avg_deviation``: the standard deviation seen on the
+ number of cycles between interrupts used to feed the pool.
+
+
randomize_va_space
==================