Mercurial > hg > nginx-quic
view src/os/unix/ngx_gcc_atomic_sparc64.h @ 7870:e169cce912c7 quic
Avoid retransmitting of packets with discarded keys.
Sections 4.10.1 and 4.10.2 of quic transport describe discarding of initial
and handshake keys. Since the keys are discarded, we no longer need
to retransmit packets and corresponding queues should be emptied.
This patch removes previously added workaround that did not require
acknowledgement for initial packets, resulting in avoiding retransmission,
which is wrong because a packet could be lost and we have to retransmit it.
author | Vladimir Homutov <vl@nginx.com> |
---|---|
date | Mon, 18 May 2020 13:54:53 +0300 |
parents | 67653855682e |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ /* * "casa [r1] 0x80, r2, r0" and * "casxa [r1] 0x80, r2, r0" do the following: * * if ([r1] == r2) { * swap(r0, [r1]); * } else { * r0 = [r1]; * } * * so "r0 == r2" means that the operation was successful. * * * The "r" means the general register. * The "+r" means the general register used for both input and output. */ #if (NGX_PTR_SIZE == 4) #define NGX_CASA "casa" #else #define NGX_CASA "casxa" #endif static ngx_inline ngx_atomic_uint_t ngx_atomic_cmp_set(ngx_atomic_t *lock, ngx_atomic_uint_t old, ngx_atomic_uint_t set) { __asm__ volatile ( NGX_CASA " [%1] 0x80, %2, %0" : "+r" (set) : "r" (lock), "r" (old) : "memory"); return (set == old); } static ngx_inline ngx_atomic_int_t ngx_atomic_fetch_add(ngx_atomic_t *value, ngx_atomic_int_t add) { ngx_atomic_uint_t old, res; old = *value; for ( ;; ) { res = old + add; __asm__ volatile ( NGX_CASA " [%1] 0x80, %2, %0" : "+r" (res) : "r" (value), "r" (old) : "memory"); if (res == old) { return res; } old = res; } } #if (NGX_SMP) #define ngx_memory_barrier() \ __asm__ volatile ( \ "membar #LoadLoad | #LoadStore | #StoreStore | #StoreLoad" \ ::: "memory") #else #define ngx_memory_barrier() __asm__ volatile ("" ::: "memory") #endif #define ngx_cpu_pause()