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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2011-04-07 14:09:50 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-04-11 12:58:19 +0200 |
| commit | dce840a08702bd13a9a186e07e63d1ef82256b5e (patch) | |
| tree | 168bb98aed7f5761ebe31aa92c34959e9d0f238a /include | |
| parent | a9c9a9b6bff27ac9c746344a9c1a19bf3327002c (diff) | |
| download | kernel_samsung_smdk4412-dce840a08702bd13a9a186e07e63d1ef82256b5e.zip kernel_samsung_smdk4412-dce840a08702bd13a9a186e07e63d1ef82256b5e.tar.gz kernel_samsung_smdk4412-dce840a08702bd13a9a186e07e63d1ef82256b5e.tar.bz2 | |
sched: Dynamically allocate sched_domain/sched_group data-structures
Instead of relying on static allocations for the sched_domain and
sched_group trees, dynamically allocate and RCU free them.
Allocating this dynamically also allows for some build_sched_groups()
simplification since we can now (like with other simplifications) rely
on the sched_domain tree instead of hard-coded knowledge.
One tricky to note is that detach_destroy_domains() needs to hold
rcu_read_lock() over the entire tear-down, per-cpu is not sufficient
since that can lead to partial sched_group existance (could possibly
be solved by doing the tear-down backwards but this is much more
robust).
A concequence of the above is that we can no longer print the
sched_domain debug stuff from cpu_attach_domain() since that might now
run with preemption disabled (due to classic RCU etc.) and
sched_domain_debug() does some GFP_KERNEL allocations.
Another thing to note is that we now fully rely on normal RCU and not
RCU-sched, this is because with the new and exiting RCU flavours we
grew over the years BH doesn't necessarily hold off RCU-sched grace
periods (-rt is known to break this). This would in fact already cause
us grief since we do sched_domain/sched_group iterations from softirq
context.
This patch is somewhat larger than I would like it to be, but I didn't
find any means of shrinking/splitting this.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.245307941@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/sched.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 4ec2c02..020b79d 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -868,6 +868,7 @@ static inline int sd_power_saving_flags(void) struct sched_group { struct sched_group *next; /* Must be a circular list */ + atomic_t ref; /* * CPU power of this group, SCHED_LOAD_SCALE being max power for a @@ -973,6 +974,10 @@ struct sched_domain { #ifdef CONFIG_SCHED_DEBUG char *name; #endif + union { + void *private; /* used during construction */ + struct rcu_head rcu; /* used during destruction */ + }; unsigned int span_weight; /* |