From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Darren Hart <darren@dvhart.com>,
Michael Kerrisk <mtk.manpages@googlemail.com>,
Davidlohr Bueso <dave@stgolabs.net>, Chris Mason <clm@fb.com>,
"Carlos O'Donell" <carlos@redhat.com>,
Torvald Riegel <triegel@redhat.com>,
Eric Dumazet <edumazet@google.com>
Subject: [patch 5/7] futex: Add sysctl knobs for process private hash
Date: Thu, 28 Apr 2016 16:42:11 -0000 [thread overview]
Message-ID: <20160428163525.759339061@linutronix.de> (raw)
In-Reply-To: 20160428161742.363543816@linutronix.de
[-- Attachment #1: add-sysctl-interface.patch --]
[-- Type: text/plain, Size: 3677 bytes --]
From: Sebastian Siewior <bigeasy@linutronix.de>
To adjust the default hash size and the maximum hash size for process private
futexes we add the following sysctls:
futex_private_default_hash_bits:
Adjusts the default hash size (in bits) which is used for automatic hash
allocations on the first futex operation
futex_private_max_hash_bits:
Adjusts the maximum hash size (in bits). This limits the hash size which
can be preallocated by applications with the FUTEX_PREALLOC_HASH op.
Signed-off-by: Sebastian Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
Documentation/sysctl/kernel.txt | 17 +++++++++++++++++
include/linux/futex.h | 1 +
kernel/futex.c | 5 +++--
kernel/sysctl.c | 21 +++++++++++++++++++++
4 files changed, 42 insertions(+), 2 deletions(-)
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -29,6 +29,8 @@ Currently, these files might (depending
- core_pipe_limit
- core_uses_pid
- ctrl-alt-del
+- futex_private_default_hash_bits
+- futex_private_max_hash_bits
- dmesg_restrict
- domainname
- hostname
@@ -265,6 +267,21 @@ to decide what to do with it.
==============================================================
+futex_private_default_hash_bits:
+
+Adjusts the default hash size (in bits) which is used for
+automatic hash allocations on the first futex operation
+
+==============================================================
+
+futex_private_max_hash_bits:
+
+Adjusts the maximum hash size (in bits). This limits the hash
+size which can be preallocated by applications with the
+FUTEX_PREALLOC_HASH op.
+
+==============================================================
+
dmesg_restrict:
This toggle indicates whether unprivileged users are prevented
--- a/include/linux/futex.h
+++ b/include/linux/futex.h
@@ -75,6 +75,7 @@ static inline void exit_pi_state_list(st
extern unsigned int futex_default_hash_bits;
extern unsigned int futex_max_hash_bits;
+extern unsigned int futex_sysmax_hash_bits;
extern void futex_mm_hash_exit(struct mm_struct *mm);
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -297,8 +297,9 @@ struct futex_hash_bucket {
#define FUTEX_DEF_HASH_BITS order_base_2(8UL)
#define FUTEX_MAX_HASH_BITS order_base_2(256UL)
-unsigned int futex_default_hash_bits = FUTEX_DEF_HASH_BITS;
-unsigned int futex_max_hash_bits = FUTEX_MAX_HASH_BITS;
+unsigned int futex_default_hash_bits = FUTEX_DEF_HASH_BITS;
+unsigned int futex_max_hash_bits = FUTEX_MAX_HASH_BITS;
+unsigned int __read_mostly futex_sysmax_hash_bits = FUTEX_MAX_HASH_BITS;
#else
static const unsigned int futex_default_hash_bits = 0;
#endif
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -65,6 +65,7 @@
#include <linux/sched/sysctl.h>
#include <linux/kexec.h>
#include <linux/bpf.h>
+#include <linux/futex.h>
#include <asm/uaccess.h>
#include <asm/processor.h>
@@ -593,6 +594,26 @@ static struct ctl_table kern_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec,
},
+#ifdef CONFIG_FUTEX_PRIVATE_HASH
+ {
+ .procname = "futex_private_default_hash_bits",
+ .data = &futex_default_hash_bits,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &two,
+ .extra2 = &futex_max_hash_bits,
+ },
+ {
+ .procname = "futex_private_max_hash_bits",
+ .data = &futex_max_hash_bits,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &futex_default_hash_bits,
+ .extra2 = &futex_sysmax_hash_bits,
+ },
+#endif
#ifdef CONFIG_FUNCTION_TRACER
{
.procname = "ftrace_enabled",
next prev parent reply other threads:[~2016-04-28 16:43 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-28 16:42 [patch 0/7] futex: Add support for process private hashing Thomas Gleixner
2016-04-28 16:42 ` [patch 1/7] futex: Add some more function commentry Thomas Gleixner
2016-04-28 16:42 ` [patch 2/7] lib/hashmod: Add modulo based hash mechanism Thomas Gleixner
2016-04-28 18:32 ` Linus Torvalds
2016-04-28 23:26 ` Thomas Gleixner
2016-04-29 2:25 ` Linus Torvalds
2016-04-30 13:02 ` Thomas Gleixner
2016-04-30 16:45 ` Eric Dumazet
2016-04-30 17:12 ` Linus Torvalds
2016-04-30 17:37 ` Eric Dumazet
2016-06-12 12:18 ` Sandy Harris
2016-04-29 21:10 ` Linus Torvalds
2016-04-29 23:51 ` Linus Torvalds
2016-04-30 1:34 ` Rik van Riel
2016-05-02 9:39 ` Torvald Riegel
2016-04-30 15:22 ` Thomas Gleixner
2016-04-28 16:42 ` [patch 3/7] futex: Hash private futexes per process Thomas Gleixner
2016-04-28 16:42 ` [patch 4/7] futex: Add op for hash preallocation Thomas Gleixner
2016-04-28 16:42 ` Thomas Gleixner [this message]
2016-04-28 16:42 ` [patch 6/7] perf/bench/futex-hash: Support NUMA Thomas Gleixner
2016-04-28 16:42 ` [patch 7/7] perf/bench/futex-hash: Support preallocate hash table Thomas Gleixner
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