xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Browse Source 
Pull module updates from Rusty Russell:
 "Main excitement here is Peter Zijlstra's lockless rbtree optimization
  to speed module address lookup.  He found some abusers of the module
  lock doing that too.

  A little bit of parameter work here too; including Dan Streetman's
  breaking up the big param mutex so writing a parameter can load
  another module (yeah, really).  Unfortunately that broke the usual
  suspects, !CONFIG_MODULES and !CONFIG_SYSFS, so those fixes were
  appended too"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (26 commits)
  modules: only use mod->param_lock if CONFIG_MODULES
  param: fix module param locks when !CONFIG_SYSFS.
  rcu: merge fix for Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE()
  module: add per-module param_lock
  module: make perm const
  params: suppress unused variable error, warn once just in case code changes.
  modules: clarify CONFIG_MODULE_COMPRESS help, suggest 'N'.
  kernel/module.c: avoid ifdefs for sig_enforce declaration
  kernel/workqueue.c: remove ifdefs over wq_power_efficient
  kernel/params.c: export param_ops_bool_enable_only
  kernel/params.c: generalize bool_enable_only
  kernel/module.c: use generic module param operaters for sig_enforce
  kernel/params: constify struct kernel_param_ops uses
  sysfs: tightened sysfs permission checks
  module: Rework module_addr_{min,max}
  module: Use __module_address() for module_address_lookup()
  module: Make the mod_tree stuff conditional on PERF_EVENTS || TRACING
  module: Optimize __module_address() using a latched RB-tree
  rbtree: Implement generic latch_tree
  seqlock: Introduce raw_read_seqcount_latch()
  ...
This commit is contained in:
Linus Torvalds
2015-07-01 10:49:25 -07:00
parent 0890a26479 20bdc2cfdb
commit 02201e3f1b
48 changed files with 887 additions and 359 deletions
Download Patch File Download Diff File Expand all files Collapse all files

29
kernel/time/timekeeping.c
View File

@@ -319,32 +319,7 @@ static inline s64 timekeeping_get_ns(struct tk_read_base *tkr)
* We want to use this from any context including NMI and tracing /
* instrumenting the timekeeping code itself.
*
* So we handle this differently than the other timekeeping accessor
* functions which retry when the sequence count has changed. The
* update side does:
*
* smp_wmb(); <- Ensure that the last base[1] update is visible
* tkf->seq++;
* smp_wmb(); <- Ensure that the seqcount update is visible
* update(tkf->base[0], tkr);
* smp_wmb(); <- Ensure that the base[0] update is visible
* tkf->seq++;
* smp_wmb(); <- Ensure that the seqcount update is visible
* update(tkf->base[1], tkr);
*
* The reader side does:
*
* do {
* seq = tkf->seq;
* smp_rmb();
* idx = seq & 0x01;
* now = now(tkf->base[idx]);
* smp_rmb();
* } while (seq != tkf->seq)
*
* As long as we update base[0] readers are forced off to
* base[1]. Once base[0] is updated readers are redirected to base[0]
* and the base[1] update takes place.
* Employ the latch technique; see @raw_write_seqcount_latch.
*
* So if a NMI hits the update of base[0] then it will use base[1]
* which is still consistent. In the worst case this can result is a
@@ -407,7 +382,7 @@ static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
u64 now;
do {
seq = raw_read_seqcount(&tkf->seq);
seq = raw_read_seqcount_latch(&tkf->seq);
tkr = tkf->base + (seq & 0x01);
now = ktime_to_ns(tkr->base) + timekeeping_get_ns(tkr);
} while (read_seqcount_retry(&tkf->seq, seq));