955387a035
Upstream commit: e3976287b22422787f3cc6fc9adda58304b55bd9 - Handle non-hostname CNAME aliases during name resolution (#2129005) - nscd: Drop local address tuple variable [BZ #29607] - x86-64: Require BMI1/BMI2 for AVX2 strrchr and wcsrchr implementations - x86-64: Require BMI2 and LZCNT for AVX2 memrchr implementation - x86-64: Require BMI2 for AVX2 (raw|w)memchr implementations - x86-64: Require BMI2 for AVX2 wcs(n)cmp implementations - x86-64: Require BMI2 for AVX2 strncmp implementation - x86-64: Require BMI2 for AVX2 strcmp implementation - x86-64: Require BMI2 for AVX2 str(n)casecmp implementations - x86: include BMI1 and BMI2 in x86-64-v3 level - nptl: Add backoff mechanism to spinlock loop - sysdeps: Add 'get_fast_jitter' interace in fast-jitter.h - nptl: Effectively skip CAS in spinlock loop - Move assignment out of the CAS condition - Add LLL_MUTEX_READ_LOCK [BZ #28537] - Avoid extra load with CAS in __pthread_mutex_clocklock_common [BZ #28537] - Avoid extra load with CAS in __pthread_mutex_lock_full [BZ #28537] - resolv: Fix building tst-resolv-invalid-cname for earlier C standards - nss_dns: Rewrite _nss_dns_gethostbyname4_r using current interfaces - resolv: Add new tst-resolv-invalid-cname - nss_dns: In gaih_getanswer_slice, skip strange aliases (bug 12154) (#2129005) - nss_dns: Rewrite getanswer_r to match getanswer_ptr (bug 12154, bug 29305) - nss_dns: Remove remnants of IPv6 address mapping - nss_dns: Rewrite _nss_dns_gethostbyaddr2_r and getanswer_ptr - nss_dns: Split getanswer_ptr from getanswer_r - resolv: Add DNS packet parsing helpers geared towards wire format - resolv: Add internal __ns_name_length_uncompressed function - resolv: Add the __ns_samebinaryname function - resolv: Add internal __res_binary_hnok function - resolv: Add tst-resolv-aliases - resolv: Add tst-resolv-byaddr for testing reverse lookup - gconv: Use 64-bit interfaces in gconv_parseconfdir (bug 29583) - elf: Fix hwcaps string size overestimation - nscd: Fix netlink cache invalidation if epoll is used [BZ #29415] - Apply asm redirections in wchar.h before first use - Apply asm redirections in stdio.h before first use [BZ #27087] - elf: Call __libc_early_init for reused namespaces (bug 29528) Reviewed-by: Florian Weimer <fweimer@redhat.com>
34 lines
1.1 KiB
Diff
34 lines
1.1 KiB
Diff
commit a2e259014f8a0e5f3ff938314f3087b74255804d
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Author: H.J. Lu <hjl.tools@gmail.com>
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Date: Thu Nov 11 06:31:51 2021 -0800
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Avoid extra load with CAS in __pthread_mutex_lock_full [BZ #28537]
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Replace boolean CAS with value CAS to avoid the extra load.
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Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
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(cherry picked from commit 0b82747dc48d5bf0871bdc6da8cb6eec1256355f)
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diff --git a/nptl/pthread_mutex_lock.c b/nptl/pthread_mutex_lock.c
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index da624f322d06d0ee..a04e0158451c8fff 100644
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--- a/nptl/pthread_mutex_lock.c
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+++ b/nptl/pthread_mutex_lock.c
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@@ -298,12 +298,12 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex)
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meantime. */
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if ((oldval & FUTEX_WAITERS) == 0)
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{
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- if (atomic_compare_and_exchange_bool_acq (&mutex->__data.__lock,
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- oldval | FUTEX_WAITERS,
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- oldval)
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- != 0)
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+ int val;
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+ if ((val = atomic_compare_and_exchange_val_acq
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+ (&mutex->__data.__lock, oldval | FUTEX_WAITERS,
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+ oldval)) != oldval)
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{
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- oldval = mutex->__data.__lock;
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+ oldval = val;
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continue;
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}
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oldval |= FUTEX_WAITERS;
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