view src/os/unix/ngx_sunpro_amd64.il @ 5992:174512857ccf

Cache: do not inherit last_modified and etag from stale response. When replacing a stale cache entry, its last_modified and etag could be inherited from the old entry if the response code is not 200 or 206. Moreover, etag could be inherited with any response code if it's missing in the new response. As a result, the cache entry is left with invalid last_modified or etag which could lead to broken revalidation. For example, when a file is deleted from backend, its last_modified is copied to the new 404 cache entry and is used later for revalidation. Once the old file appears again with its original timestamp, revalidation succeeds and the cached 404 response is sent to client instead of the file. The problem appeared with etags in 44b9ab7752e3 (1.7.3) and affected last_modified in 1573fc7875fa (1.7.9).
author Roman Arutyunyan <arut@nginx.com>
date Mon, 02 Mar 2015 19:47:13 +0300
parents d620f497c50f
children 2cd019520210
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/
/ Copyright (C) Igor Sysoev
/ Copyright (C) Nginx, Inc.
/

/ ngx_atomic_uint_t ngx_atomic_cmp_set(ngx_atomic_t *lock,
/     ngx_atomic_uint_t old, ngx_atomic_uint_t set);
/
/ the arguments are passed in %rdi, %rsi, %rdx
/ the result is returned in the %rax

        .inline ngx_atomic_cmp_set,0
        movq      %rsi, %rax
        lock
        cmpxchgq  %rdx, (%rdi)
        setz      %al
        movzbq    %al, %rax
        .end


/ ngx_atomic_int_t ngx_atomic_fetch_add(ngx_atomic_t *value,
/     ngx_atomic_int_t add);
/
/ the arguments are passed in %rdi, %rsi
/ the result is returned in the %rax

        .inline ngx_atomic_fetch_add,0
        movq      %rsi, %rax
        lock
        xaddq     %rax, (%rdi)
        .end


/ ngx_cpu_pause()
/
/ the "rep; nop" is used instead of "pause" to avoid the "[ PAUSE ]" hardware
/ capability added by linker because Solaris/amd64 does not know about it:
/
/ ld.so.1: nginx: fatal: hardware capability unsupported: 0x2000 [ PAUSE ]

       .inline ngx_cpu_pause,0
       rep; nop
       .end