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2017-04-27docs: Fix a couple typosStan Drozd1-1/+1
This commit gets rid of some minor errors in Documentation/: * cputopology.txt: drawes -> drawers * debugging-via-ohci1394.txt: remove an unnecessary line break * static-keys: statemnts -> statements * zorro.txt: busses -> buses Signed-off-by: Stan Drozd <drozdziak1@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-02-15jump_label: Reduce the size of struct static_keyJason Baron1-1/+3
The static_key->next field goes mostly unused. The field is used for associating module uses with a static key. Most uses of struct static_key define a static key in the core kernel and make use of it entirely within the core kernel, or define the static key in a module and make use of it only from within that module. In fact, of the ~3,000 static keys defined, I found only about 5 or so that did not fit this pattern. Thus, we can remove the static_key->next field entirely and overload the static_key->entries field. That is, when all the static_key uses are contained within the same module, static_key->entries continues to point to those uses. However, if the static_key uses are not contained within the module where the static_key is defined, then we allocate a struct static_key_mod, store a pointer to the uses within that struct static_key_mod, and have the static key point at the static_key_mod. This does incur some extra memory usage when a static_key is used in a module that does not define it, but since there are only a handful of such cases there is a net savings. In order to identify if the static_key->entries pointer contains a struct static_key_mod or a struct jump_entry pointer, bit 1 of static_key->entries is set to 1 if it points to a struct static_key_mod and is 0 if it points to a struct jump_entry. We were already using bit 0 in a similar way to store the initial value of the static_key. This does mean that allocations of struct static_key_mod and that the struct jump_entry tables need to be at least 4-byte aligned in memory. As far as I can tell all arches meet this criteria. For my .config, the patch increased the text by 778 bytes, but reduced the data + bss size by 14912, for a net savings of 14,134 bytes. text data bss dec hex filename 8092427 5016512 790528 13899467 d416cb vmlinux.pre 8093205 5001600 790528 13885333 d3df95 vmlinux.post Link: http://lkml.kernel.org/r/1486154544-4321-1-git-send-email-jbaron@akamai.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Joe Perches <joe@perches.com> Signed-off-by: Jason Baron <jbaron@akamai.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2016-09-07jump_labels: Allow array initialisersCatalin Marinas1-0/+9
The static key API is currently designed around single variable definitions. There are cases where an array of static keys is desirable, so extend the API to allow this rather than using the internal static key implementation directly. Cc: Jason Baron <jbaron@akamai.com> Cc: Jonathan Corbet <corbet@lwn.net> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Suggested-by: Dave P Martin <Dave.Martin@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-09-15locking/static_keys: Fix up the static keys documentationJonathan Corbet1-2/+2
Fix a few small mistakes in the static key documentation and delete an unneeded sentence. Suggested-by: Jason Baron <jbaron@akamai.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150914171105.511e1e21@lwn.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-08locking/static_keys: Fix a silly typoJonathan Corbet1-1/+1
Commit: 412758cb2670 ("jump label, locking/static_keys: Update docs") introduced a typo that might as well get fixed. Signed-off-by: Jonathan Corbet <corbet@lwn.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jason Baron <jbaron@akamai.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150907131803.54c027e1@lwn.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-03jump label, locking/static_keys: Update docsJason Baron1-47/+52
Signed-off-by: Jason Baron <jbaron@akamai.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: benh@kernel.crashing.org Cc: bp@alien8.de Cc: davem@davemloft.net Cc: ddaney@caviumnetworks.com Cc: heiko.carstens@de.ibm.com Cc: linux-kernel@vger.kernel.org Cc: liuj97@gmail.com Cc: luto@amacapital.net Cc: michael@ellerman.id.au Cc: rabin@rab.in Cc: ralf@linux-mips.org Cc: rostedt@goodmis.org Cc: vbabka@suse.cz Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/6b50f2f6423a2244f37f4b1d2d6c211b9dcdf4f8.1438227999.git.jbaron@akamai.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-02doc: fix some typos in documentationsXishi Qiu1-2/+2
Fix some typos in five documentations, no functional change. Signed-off-by: Xishi Qiu <qiuxishi@huawei.com> Acked-by: Rob Landley <rob@landley.net> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2012-04-16Documentation: Fix typo in multiple files in DocumentationMasanari Iida1-1/+1
Correct multiple spelling typo in Documentation. Signed-off-by: Masanari Iida <standby24x7@gmail.com> Acked-by: Rob Landley <rob@landley.net> Reported-by: Anders Larsen <al@alarsen.net> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2012-02-24static keys: Add docs better explaining the whole 'struct static_key' mechanismJason Baron1-0/+286
Add better documentation for static keys. Signed-off-by: Jason Baron <jbaron@redhat.com> Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: davem@davemloft.net Cc: ddaney.cavm@gmail.com Cc: a.p.zijlstra@chello.nl Link: http://lkml.kernel.org/r/52570e566e5f1914f27b67e4eafb5781b8f9f9db.1329851692.git.jbaron@redhat.com [ Added a 'Summary' section and rewrote it to explain static keys ] Signed-off-by: Ingo Molnar <mingo@elte.hu>