[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH 1/5] xen/domain: Remove function pointers from domain pause helpers
Retpolines are expensive, and all these do are select between the sync and nosync helpers. Pass a boolean instead, and use direct calls everywhere. Pause/unpause operations on behalf of dom0 are not fastpaths, so avoid exposing the __domain_pause_by_systemcontroller() internal. This actually compiles smaller than before: $ ../scripts/bloat-o-meter xen-syms-before xen-syms-after add/remove: 3/1 grow/shrink: 0/5 up/down: 250/-273 (-23) Function old new delta _domain_pause - 115 +115 domain_pause_by_systemcontroller - 69 +69 domain_pause_by_systemcontroller_nosync - 66 +66 domain_kill 426 398 -28 domain_resume 246 214 -32 domain_pause_except_self 189 141 -48 domain_pause 59 10 -49 domain_pause_nosync 59 7 -52 __domain_pause_by_systemcontroller 64 - -64 despite GCC's best efforts. The new _domain_pause_by_systemcontroller() really should not be inlined, considering that the difference is only the setup of the sync boolean to pass to _domain_pause(), and there are plenty of registers to spare. Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> --- CC: Jan Beulich <JBeulich@xxxxxxxx> CC: Roger Pau Monné <roger.pau@xxxxxxxxxx> CC: Wei Liu <wl@xxxxxxx> CC: Stefano Stabellini <sstabellini@xxxxxxxxxx> CC: Julien Grall <julien@xxxxxxx> CC: Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx> CC: Bertrand Marquis <bertrand.marquis@xxxxxxx> --- xen/common/domain.c | 31 ++++++++++++++++++++++--------- xen/include/xen/sched.h | 15 +++++---------- 2 files changed, 27 insertions(+), 19 deletions(-) diff --git a/xen/common/domain.c b/xen/common/domain.c index 56d47dd66478..562872cdf87a 100644 --- a/xen/common/domain.c +++ b/xen/common/domain.c @@ -1234,15 +1234,18 @@ int vcpu_unpause_by_systemcontroller(struct vcpu *v) return 0; } -static void do_domain_pause(struct domain *d, - void (*sleep_fn)(struct vcpu *v)) +static void _domain_pause(struct domain *d, bool sync /* or nosync */) { struct vcpu *v; atomic_inc(&d->pause_count); - for_each_vcpu( d, v ) - sleep_fn(v); + if ( sync ) + for_each_vcpu ( d, v ) + vcpu_sleep_sync(v); + else + for_each_vcpu ( d, v ) + vcpu_sleep_nosync(v); arch_domain_pause(d); } @@ -1250,12 +1253,12 @@ static void do_domain_pause(struct domain *d, void domain_pause(struct domain *d) { ASSERT(d != current->domain); - do_domain_pause(d, vcpu_sleep_sync); + _domain_pause(d, true /* sync */); } void domain_pause_nosync(struct domain *d) { - do_domain_pause(d, vcpu_sleep_nosync); + _domain_pause(d, false /* nosync */); } void domain_unpause(struct domain *d) @@ -1269,8 +1272,8 @@ void domain_unpause(struct domain *d) vcpu_wake(v); } -int __domain_pause_by_systemcontroller(struct domain *d, - void (*pause_fn)(struct domain *d)) +static int _domain_pause_by_systemcontroller( + struct domain *d, bool sync /* or nosync */) { int old, new, prev = d->controller_pause_count; @@ -1289,11 +1292,21 @@ int __domain_pause_by_systemcontroller(struct domain *d, prev = cmpxchg(&d->controller_pause_count, old, new); } while ( prev != old ); - pause_fn(d); + _domain_pause(d, sync); return 0; } +int domain_pause_by_systemcontroller(struct domain *d) +{ + return _domain_pause_by_systemcontroller(d, true /* sync */); +} + +int domain_pause_by_systemcontroller_nosync(struct domain *d) +{ + return _domain_pause_by_systemcontroller(d, false /* nosync */); +} + int domain_unpause_by_systemcontroller(struct domain *d) { int old, new, prev = d->controller_pause_count; diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h index 28146ee404e6..37f78cc4c4c9 100644 --- a/xen/include/xen/sched.h +++ b/xen/include/xen/sched.h @@ -920,26 +920,21 @@ static inline bool vcpu_cpu_dirty(const struct vcpu *v) void vcpu_block(void); void vcpu_unblock(struct vcpu *v); + void vcpu_pause(struct vcpu *v); void vcpu_pause_nosync(struct vcpu *v); void vcpu_unpause(struct vcpu *v); + int vcpu_pause_by_systemcontroller(struct vcpu *v); int vcpu_unpause_by_systemcontroller(struct vcpu *v); void domain_pause(struct domain *d); void domain_pause_nosync(struct domain *d); void domain_unpause(struct domain *d); + +int domain_pause_by_systemcontroller(struct domain *d); +int domain_pause_by_systemcontroller_nosync(struct domain *d); int domain_unpause_by_systemcontroller(struct domain *d); -int __domain_pause_by_systemcontroller(struct domain *d, - void (*pause_fn)(struct domain *d)); -static inline int domain_pause_by_systemcontroller(struct domain *d) -{ - return __domain_pause_by_systemcontroller(d, domain_pause); -} -static inline int domain_pause_by_systemcontroller_nosync(struct domain *d) -{ - return __domain_pause_by_systemcontroller(d, domain_pause_nosync); -} /* domain_pause() but safe against trying to pause current. */ int __must_check domain_pause_except_self(struct domain *d); -- 2.11.0
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