- 17 8月, 2020 1 次提交
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由 c00346986 提交于
Description:kernelspace musl code Team:OTHERS Feature or Bugfix:Feature Binary Source:NA PrivateCode(Yes/No):No Change-Id: I99874a7c570b7d22b4a3d34840260eb48ea3ffa1 Reviewed-on: http://mgit-tm.rnd.huawei.com/10276995Reviewed-by: Nshenwei 00579521 <denny.shenwei@huawei.com> Tested-by: Npublic jenkins <public_jenkins@notesmail.huawei.com>
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- 13 9月, 2018 1 次提交
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由 Rich Felker 提交于
this further reduces the number of source files which need to include libc.h and thereby be potentially exposed to libc global state and internals. this will also facilitate further improvements like adding an inline fast-path, if we want to do so later.
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- 10 1月, 2018 1 次提交
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由 Jens Gustedt 提交于
In all cases this is just a change from two volatile int to one.
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- 04 3月, 2015 1 次提交
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由 Rich Felker 提交于
the memory model we use internally for atomics permits plain loads of values which may be subject to concurrent modification without requiring that a special load function be used. since a compiler is free to make transformations that alter the number of loads or the way in which loads are performed, the compiler is theoretically free to break this usage. the most obvious concern is with atomic cas constructs: something of the form tmp=*p;a_cas(p,tmp,f(tmp)); could be transformed to a_cas(p,*p,f(*p)); where the latter is intended to show multiple loads of *p whose resulting values might fail to be equal; this would break the atomicity of the whole operation. but even more fundamental breakage is possible. with the changes being made now, objects that may be modified by atomics are modeled as volatile, and the atomic operations performed on them by other threads are modeled as asynchronous stores by hardware which happens to be acting on the request of another thread. such modeling of course does not itself address memory synchronization between cores/cpus, but that aspect was already handled. this all seems less than ideal, but it's the best we can do without mandating a C11 compiler and using the C11 model for atomics. in the case of pthread_once_t, the ABI type of the underlying object is not volatile-qualified. so we are assuming that accessing the object through a volatile-qualified lvalue via casts yields volatile access semantics. the language of the C standard is somewhat unclear on this matter, but this is an assumption the linux kernel also makes, and seems to be the correct interpretation of the standard.
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- 21 1月, 2014 1 次提交
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由 Szabolcs Nagy 提交于
setstate could use the results of previous initstate or setstate calls (they return the old state buffer), but the documentation requires that an initialized state buffer should be possible to use in setstate immediately, which means that initstate should save the generator parameters in it. I also removed the copyright notice since it is present in the copyright file.
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- 25 4月, 2012 1 次提交
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由 Rich Felker 提交于
i did some testing trying to switch malloc to use the new internal lock with priority inheritance, and my malloc contention test got 20-100 times slower. if priority inheritance futexes are this slow, it's simply too high a price to pay for avoiding priority inversion. maybe we can consider them somewhere down the road once the kernel folks get their act together on this (and perferably don't link it to glibc's inefficient lock API)... as such, i've switch __lock to use malloc's implementation of lightweight locks, and updated all the users of the code to use an array with a waiter count for their locks. this should give optimal performance in the vast majority of cases, and it's simple. malloc is still using its own internal copy of the lock code because it seems to yield measurably better performance with -O3 when it's inlined (20% or more difference in the contention stress test).
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- 30 6月, 2011 1 次提交
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由 Rich Felker 提交于
these interfaces are required to be thread-safe even though they are not state-free. the random number sequence is shared across all threads.
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- 24 6月, 2011 1 次提交
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由 Rich Felker 提交于
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- 12 2月, 2011 1 次提交
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由 Rich Felker 提交于
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