diff options
author | Ingo Molnar <mingo@kernel.org> | 2012-04-13 09:50:21 +0200 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2012-04-13 09:50:21 +0200 |
commit | 659c36fcda403013a01b85da07cf2d9711e6d6c7 (patch) | |
tree | ece2e7d0e2c19ea5a3d0ec172ad0b81a8a19021d /include/linux/cpuset.h | |
parent | 9521d830b6341d1887dcfc2aebde23fbfa5f1473 (diff) | |
parent | 5a7ed29c7572d00a75e8c4529e30c5ac2ef82271 (diff) |
Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core
Fixes and improvements for perf/core:
. Overhaul the tools/ makefiles, gluing them to the top level Makefile, from
Borislav Petkov.
. Move the UI files from tools/perf/util/ui/ to tools/perf/ui/. Also move
the GTK+ browser to tools/perf/ui/gtk/, from Namhyung Kim.
. Only fallback to sw cycles counter on ENOENT for the hw cycles, from
Robert Richter
. Trivial fixes from Robert Richter
. Handle the autogenerated bison/flex files better, from Namhyung and Jiri Olsa.
. Navigate jump instructions in the annotate browser, just press enter or ->,
still needs support for a jump navigation history, i.e. to go back.
. Search string in the annotate browser: same keys as vim:
/ forward
n next backward/forward
? backward
. Clarify number of events/samples in the report header, from Ashay Rane
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/cpuset.h')
-rw-r--r-- | include/linux/cpuset.h | 47 |
1 files changed, 20 insertions, 27 deletions
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h index e9eaec52265..7a7e5fd2a27 100644 --- a/include/linux/cpuset.h +++ b/include/linux/cpuset.h @@ -89,42 +89,33 @@ extern void rebuild_sched_domains(void); extern void cpuset_print_task_mems_allowed(struct task_struct *p); /* - * reading current mems_allowed and mempolicy in the fastpath must protected - * by get_mems_allowed() + * get_mems_allowed is required when making decisions involving mems_allowed + * such as during page allocation. mems_allowed can be updated in parallel + * and depending on the new value an operation can fail potentially causing + * process failure. A retry loop with get_mems_allowed and put_mems_allowed + * prevents these artificial failures. */ -static inline void get_mems_allowed(void) +static inline unsigned int get_mems_allowed(void) { - current->mems_allowed_change_disable++; - - /* - * ensure that reading mems_allowed and mempolicy happens after the - * update of ->mems_allowed_change_disable. - * - * the write-side task finds ->mems_allowed_change_disable is not 0, - * and knows the read-side task is reading mems_allowed or mempolicy, - * so it will clear old bits lazily. - */ - smp_mb(); + return read_seqcount_begin(¤t->mems_allowed_seq); } -static inline void put_mems_allowed(void) +/* + * If this returns false, the operation that took place after get_mems_allowed + * may have failed. It is up to the caller to retry the operation if + * appropriate. + */ +static inline bool put_mems_allowed(unsigned int seq) { - /* - * ensure that reading mems_allowed and mempolicy before reducing - * mems_allowed_change_disable. - * - * the write-side task will know that the read-side task is still - * reading mems_allowed or mempolicy, don't clears old bits in the - * nodemask. - */ - smp_mb(); - --ACCESS_ONCE(current->mems_allowed_change_disable); + return !read_seqcount_retry(¤t->mems_allowed_seq, seq); } static inline void set_mems_allowed(nodemask_t nodemask) { task_lock(current); + write_seqcount_begin(¤t->mems_allowed_seq); current->mems_allowed = nodemask; + write_seqcount_end(¤t->mems_allowed_seq); task_unlock(current); } @@ -234,12 +225,14 @@ static inline void set_mems_allowed(nodemask_t nodemask) { } -static inline void get_mems_allowed(void) +static inline unsigned int get_mems_allowed(void) { + return 0; } -static inline void put_mems_allowed(void) +static inline bool put_mems_allowed(unsigned int seq) { + return true; } #endif /* !CONFIG_CPUSETS */ |