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From: Xiaoming Ni <nixiaoming@huawei.com>
To: <triegel@redhat.com>, <carlos@redhat.com>, <davem@davemloft.net>,
	<dvhart@infradead.org>, <libc-alpha@sourceware.org>,
	<1464268895.17104.14.camel@localhost.localdomain>
Subject: Question: Is "maxspin=0" in pthread_cond_wait.c dead code or bug?
Date: Mon, 14 Nov 2022 11:32:10 +0800	[thread overview]
Message-ID: <6cd63ad4-d8d4-8171-781c-a04ea305444f@huawei.com> (raw)

nptl/pthread_cond_common.c:204:  const unsigned int maxspin = 0;
nptl/pthread_cond_common.c:259:      for (unsigned int spin = maxspin; 
((r >> 1) > 0) && (spin > 0); spin--)

"(spin > 0)" is a conditional judgment that is always false.

nptl/pthread_cond_wait.c:382:  const int maxspin = 0;
nptl/pthread_cond_wait.c:448:	  unsigned int spin = maxspin;
nptl/pthread_cond_wait.c:449:	  while (signals == 0 && spin > 0)
nptl/pthread_cond_wait.c:460:	      spin--;

"(spin > 0)" is a conditional judgment that is always false.

It's been six years since 2016,
commit ed19993b5b ("New condvar implementation that provides stronger 
ordering guarantees.")
https://public-inbox.org/libc-alpha/1464268895.17104.14.camel@localhost.localdomain

Is this a logic bug caused by a mistake, or is it just useless 
deleteable code?

Thanks
Xiaoming Ni

             reply	other threads:[~2022-11-14  3:32 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-14  3:32 Xiaoming Ni [this message]
2022-11-17 17:40 ` Adhemerval Zanella Netto

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