From a8d154b009168337494fbf345671bab74d3e4b8b Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 10 Apr 2009 09:36:00 -0400 Subject: tracing: create automated trace defines This patch lowers the number of places a developer must modify to add new tracepoints. The current method to add a new tracepoint into an existing system is to write the trace point macro in the trace header with one of the macros TRACE_EVENT, TRACE_FORMAT or DECLARE_TRACE, then they must add the same named item into the C file with the macro DEFINE_TRACE(name) and then add the trace point. This change cuts out the needing to add the DEFINE_TRACE(name). Every file that uses the tracepoint must still include the trace/.h file, but the one C file must also add a define before the including of that file. #define CREATE_TRACE_POINTS #include This will cause the trace/mytrace.h file to also produce the C code necessary to implement the trace point. Note, if more than one trace/.h is used to create the C code it is best to list them all together. #define CREATE_TRACE_POINTS #include #include #include Thanks to Mathieu Desnoyers and Christoph Hellwig for coming up with the cleaner solution of the define above the includes over my first design to have the C code include a "special" header. This patch converts sched, irq and lockdep and skb to use this new method. Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Neil Horman Cc: Zhao Lei Cc: Eduard - Gabriel Munteanu Cc: Pekka Enberg Signed-off-by: Steven Rostedt --- mm/util.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) (limited to 'mm/util.c') diff --git a/mm/util.c b/mm/util.c index 2599e83eea17..0e74a22791cb 100644 --- a/mm/util.c +++ b/mm/util.c @@ -4,9 +4,11 @@ #include #include #include -#include #include +#define CREATE_TRACE_POINTS +#include + /** * kstrdup - allocate space for and copy an existing string * @s: the string to duplicate @@ -239,13 +241,6 @@ int __attribute__((weak)) get_user_pages_fast(unsigned long start, EXPORT_SYMBOL_GPL(get_user_pages_fast); /* Tracepoints definitions. */ -DEFINE_TRACE(kmalloc); -DEFINE_TRACE(kmem_cache_alloc); -DEFINE_TRACE(kmalloc_node); -DEFINE_TRACE(kmem_cache_alloc_node); -DEFINE_TRACE(kfree); -DEFINE_TRACE(kmem_cache_free); - EXPORT_TRACEPOINT_SYMBOL(kmalloc); EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); EXPORT_TRACEPOINT_SYMBOL(kmalloc_node); -- cgit v1.2.3 From ad8d75fff811a6a230f7f43b05a6483099349533 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 14 Apr 2009 19:39:12 -0400 Subject: tracing/events: move trace point headers into include/trace/events Impact: clean up Create a sub directory in include/trace called events to keep the trace point headers in their own separate directory. Only headers that declare trace points should be defined in this directory. Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Neil Horman Cc: Zhao Lei Cc: Eduard - Gabriel Munteanu Cc: Pekka Enberg Signed-off-by: Steven Rostedt --- mm/util.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/util.c') diff --git a/mm/util.c b/mm/util.c index 0e74a22791cb..6794a336e9af 100644 --- a/mm/util.c +++ b/mm/util.c @@ -7,7 +7,7 @@ #include #define CREATE_TRACE_POINTS -#include +#include /** * kstrdup - allocate space for and copy an existing string -- cgit v1.2.3 From a234bdc9aecc299ba41ffe8023b3ea110df9f51b Mon Sep 17 00:00:00 2001 From: Pekka Enberg Date: Sun, 31 May 2009 13:50:38 +0300 Subject: slab: document kzfree() zeroing behavior As suggested by Alan Cox, document the fact that kzfree() can zero out a great deal more memory than the what the user requested from kmalloc(). Cc: Alan Cox Signed-off-by: Pekka Enberg --- mm/util.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'mm/util.c') diff --git a/mm/util.c b/mm/util.c index 55bef160b9f1..e79572b3684c 100644 --- a/mm/util.c +++ b/mm/util.c @@ -166,6 +166,10 @@ EXPORT_SYMBOL(krealloc); * * The memory of the object @p points to is zeroed before freed. * If @p is %NULL, kzfree() does nothing. + * + * Note: this function zeroes the whole allocated buffer which can be a good + * deal bigger than the requested buffer size passed to kmalloc(). So be + * careful when using this function in performance sensitive code. */ void kzfree(const void *p) { -- cgit v1.2.3 From d2bf6be8ab63aa84e6149aac934649aadf3828b1 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Tue, 16 Jun 2009 15:31:39 -0700 Subject: mm: clean up get_user_pages_fast() documentation Move more documentation for get_user_pages_fast into the new kerneldoc comment. Add some comments for get_user_pages as well. Also, move get_user_pages_fast declaration up to get_user_pages. It wasn't there initially because it was once a static inline function. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Nick Piggin Cc: Andy Grover Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/util.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) (limited to 'mm/util.c') diff --git a/mm/util.c b/mm/util.c index abc65aa7cdfc..d5d2213728c5 100644 --- a/mm/util.c +++ b/mm/util.c @@ -233,13 +233,21 @@ void arch_pick_mmap_layout(struct mm_struct *mm) * @pages: array that receives pointers to the pages pinned. * Should be at least nr_pages long. * - * Attempt to pin user pages in memory without taking mm->mmap_sem. - * If not successful, it will fall back to taking the lock and - * calling get_user_pages(). - * * Returns number of pages pinned. This may be fewer than the number * requested. If nr_pages is 0 or negative, returns 0. If no pages * were pinned, returns -errno. + * + * get_user_pages_fast provides equivalent functionality to get_user_pages, + * operating on current and current->mm, with force=0 and vma=NULL. However + * unlike get_user_pages, it must be called without mmap_sem held. + * + * get_user_pages_fast may take mmap_sem and page table locks, so no + * assumptions can be made about lack of locking. get_user_pages_fast is to be + * implemented in a way that is advantageous (vs get_user_pages()) when the + * user memory area is already faulted in and present in ptes. However if the + * pages have to be faulted in, it may turn out to be slightly slower so + * callers need to carefully consider what to use. On many architectures, + * get_user_pages_fast simply falls back to get_user_pages. */ int __attribute__((weak)) get_user_pages_fast(unsigned long start, int nr_pages, int write, struct page **pages) -- cgit v1.2.3