Mercurial > hg > nginx-quic
view src/os/win32/ngx_shmem.c @ 6422:768e287a6f36
Fixed sendfile in threads (or with aio preload) and subrequests.
If sendfile in threads is used, it is possible that multiple
subrequests will trigger multiple ngx_linux_sendfile_thread() calls,
as operations are only serialized in output chain based on r->aio,
that is, on subrequest level.
This resulted in "task #N already active" alerts, in particular, when
running proxy_store.t with "aio threads; sendfile on;".
Fix is to tolerate duplicate calls, with an additional safety check
that the file is the same as previously used.
The same problem also affects "aio on; sendfile on;" on FreeBSD
(previously known as "aio sendfile;"), where aio->preload_handler()
could be called multiple times due to similar reasons, resulting in
"second aio post" alerts. Fix is the same as well.
It is also believed that similar problems can arise if a filter
calls the next body filter multiple times for some reason. These are
mostly theoretical though.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 03 Mar 2016 21:14:12 +0300 |
parents | af7eba90645d |
children |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> /* * Base addresses selected by system for shared memory mappings are likely * to be different on Windows Vista and later versions due to address space * layout randomization. This is however incompatible with storing absolute * addresses within the shared memory. * * To make it possible to store absolute addresses we create mappings * at the same address in all processes by starting mappings at predefined * addresses. The addresses were selected somewhat randomly in order to * minimize the probability that some other library doing something similar * conflicts with us. The addresses are from the following typically free * blocks: * * - 0x10000000 .. 0x70000000 (about 1.5 GB in total) on 32-bit platforms * - 0x000000007fff0000 .. 0x000007f68e8b0000 (about 8 TB) on 64-bit platforms * * Additionally, we allow to change the mapping address once it was detected * to be different from one originally used. This is needed to support * reconfiguration. */ #ifdef _WIN64 #define NGX_SHMEM_BASE 0x0000047047e00000 #else #define NGX_SHMEM_BASE 0x2efe0000 #endif ngx_uint_t ngx_allocation_granularity; ngx_int_t ngx_shm_alloc(ngx_shm_t *shm) { u_char *name; uint64_t size; static u_char *base = (u_char *) NGX_SHMEM_BASE; name = ngx_alloc(shm->name.len + 2 + NGX_INT32_LEN, shm->log); if (name == NULL) { return NGX_ERROR; } (void) ngx_sprintf(name, "%V_%s%Z", &shm->name, ngx_unique); ngx_set_errno(0); size = shm->size; shm->handle = CreateFileMapping(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, (u_long) (size >> 32), (u_long) (size & 0xffffffff), (char *) name); if (shm->handle == NULL) { ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno, "CreateFileMapping(%uz, %s) failed", shm->size, name); ngx_free(name); return NGX_ERROR; } ngx_free(name); if (ngx_errno == ERROR_ALREADY_EXISTS) { shm->exists = 1; } shm->addr = MapViewOfFileEx(shm->handle, FILE_MAP_WRITE, 0, 0, 0, base); if (shm->addr != NULL) { base += ngx_align(size, ngx_allocation_granularity); return NGX_OK; } ngx_log_debug3(NGX_LOG_DEBUG_CORE, shm->log, ngx_errno, "MapViewOfFileEx(%uz, %p) of file mapping \"%V\" failed, " "retry without a base address", shm->size, base, &shm->name); /* * Order of shared memory zones may be different in the master process * and worker processes after reconfiguration. As a result, the above * may fail due to a conflict with a previously created mapping remapped * to a different address. Additionally, there may be a conflict with * some other uses of the memory. In this case we retry without a base * address to let the system assign the address itself. */ shm->addr = MapViewOfFile(shm->handle, FILE_MAP_WRITE, 0, 0, 0); if (shm->addr != NULL) { return NGX_OK; } ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno, "MapViewOfFile(%uz) of file mapping \"%V\" failed", shm->size, &shm->name); if (CloseHandle(shm->handle) == 0) { ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno, "CloseHandle() of file mapping \"%V\" failed", &shm->name); } return NGX_ERROR; } ngx_int_t ngx_shm_remap(ngx_shm_t *shm, u_char *addr) { if (UnmapViewOfFile(shm->addr) == 0) { ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno, "UnmapViewOfFile(%p) of file mapping \"%V\" failed", shm->addr, &shm->name); return NGX_ERROR; } shm->addr = MapViewOfFileEx(shm->handle, FILE_MAP_WRITE, 0, 0, 0, addr); if (shm->addr != NULL) { return NGX_OK; } ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno, "MapViewOfFileEx(%uz, %p) of file mapping \"%V\" failed", shm->size, addr, &shm->name); return NGX_ERROR; } void ngx_shm_free(ngx_shm_t *shm) { if (UnmapViewOfFile(shm->addr) == 0) { ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno, "UnmapViewOfFile(%p) of file mapping \"%V\" failed", shm->addr, &shm->name); } if (CloseHandle(shm->handle) == 0) { ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno, "CloseHandle() of file mapping \"%V\" failed", &shm->name); } }