Mercurial > hg > nginx
view src/http/ngx_http_write_filter_module.c @ 7985:ec2e6893caaa
Simplified sendfile(SF_NODISKIO) usage.
Starting with FreeBSD 11, there is no need to use AIO operations to preload
data into cache for sendfile(SF_NODISKIO) to work. Instead, sendfile()
handles non-blocking loading data from disk by itself. It still can, however,
return EBUSY if a page is already being loaded (for example, by a different
process). If this happens, we now post an event for the next event loop
iteration, so sendfile() is retried "after a short period", as manpage
recommends.
The limit of the number of EBUSY tolerated without any progress is preserved,
but now it does not result in an alert, since on an idle system event loop
iteration might be very short and EBUSY can happen many times in a row.
Instead, SF_NODISKIO is simply disabled for one call once the limit is
reached.
With this change, sendfile(SF_NODISKIO) is now used automatically as long as
sendfile() is enabled, and no longer requires "aio on;".
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 27 Dec 2021 19:48:33 +0300 |
parents | 51a260276425 |
children | 32b0ba4855a6 61d0fa67b55e |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> static ngx_int_t ngx_http_write_filter_init(ngx_conf_t *cf); static ngx_http_module_t ngx_http_write_filter_module_ctx = { NULL, /* preconfiguration */ ngx_http_write_filter_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ NULL, /* create location configuration */ NULL, /* merge location configuration */ }; ngx_module_t ngx_http_write_filter_module = { NGX_MODULE_V1, &ngx_http_write_filter_module_ctx, /* module context */ NULL, /* module directives */ NGX_HTTP_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ NULL, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; ngx_int_t ngx_http_write_filter(ngx_http_request_t *r, ngx_chain_t *in) { off_t size, sent, nsent, limit; ngx_uint_t last, flush, sync; ngx_msec_t delay; ngx_chain_t *cl, *ln, **ll, *chain; ngx_connection_t *c; ngx_http_core_loc_conf_t *clcf; c = r->connection; if (c->error) { return NGX_ERROR; } size = 0; flush = 0; sync = 0; last = 0; ll = &r->out; /* find the size, the flush point and the last link of the saved chain */ for (cl = r->out; cl; cl = cl->next) { ll = &cl->next; ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0, "write old buf t:%d f:%d %p, pos %p, size: %z " "file: %O, size: %O", cl->buf->temporary, cl->buf->in_file, cl->buf->start, cl->buf->pos, cl->buf->last - cl->buf->pos, cl->buf->file_pos, cl->buf->file_last - cl->buf->file_pos); if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "zero size buf in writer " "t:%d r:%d f:%d %p %p-%p %p %O-%O", cl->buf->temporary, cl->buf->recycled, cl->buf->in_file, cl->buf->start, cl->buf->pos, cl->buf->last, cl->buf->file, cl->buf->file_pos, cl->buf->file_last); ngx_debug_point(); return NGX_ERROR; } if (ngx_buf_size(cl->buf) < 0) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "negative size buf in writer " "t:%d r:%d f:%d %p %p-%p %p %O-%O", cl->buf->temporary, cl->buf->recycled, cl->buf->in_file, cl->buf->start, cl->buf->pos, cl->buf->last, cl->buf->file, cl->buf->file_pos, cl->buf->file_last); ngx_debug_point(); return NGX_ERROR; } size += ngx_buf_size(cl->buf); if (cl->buf->flush || cl->buf->recycled) { flush = 1; } if (cl->buf->sync) { sync = 1; } if (cl->buf->last_buf) { last = 1; } } /* add the new chain to the existent one */ for (ln = in; ln; ln = ln->next) { cl = ngx_alloc_chain_link(r->pool); if (cl == NULL) { return NGX_ERROR; } cl->buf = ln->buf; *ll = cl; ll = &cl->next; ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0, "write new buf t:%d f:%d %p, pos %p, size: %z " "file: %O, size: %O", cl->buf->temporary, cl->buf->in_file, cl->buf->start, cl->buf->pos, cl->buf->last - cl->buf->pos, cl->buf->file_pos, cl->buf->file_last - cl->buf->file_pos); if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "zero size buf in writer " "t:%d r:%d f:%d %p %p-%p %p %O-%O", cl->buf->temporary, cl->buf->recycled, cl->buf->in_file, cl->buf->start, cl->buf->pos, cl->buf->last, cl->buf->file, cl->buf->file_pos, cl->buf->file_last); ngx_debug_point(); return NGX_ERROR; } if (ngx_buf_size(cl->buf) < 0) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "negative size buf in writer " "t:%d r:%d f:%d %p %p-%p %p %O-%O", cl->buf->temporary, cl->buf->recycled, cl->buf->in_file, cl->buf->start, cl->buf->pos, cl->buf->last, cl->buf->file, cl->buf->file_pos, cl->buf->file_last); ngx_debug_point(); return NGX_ERROR; } size += ngx_buf_size(cl->buf); if (cl->buf->flush || cl->buf->recycled) { flush = 1; } if (cl->buf->sync) { sync = 1; } if (cl->buf->last_buf) { last = 1; } } *ll = NULL; ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0, "http write filter: l:%ui f:%ui s:%O", last, flush, size); clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); /* * avoid the output if there are no last buf, no flush point, * there are the incoming bufs and the size of all bufs * is smaller than "postpone_output" directive */ if (!last && !flush && in && size < (off_t) clcf->postpone_output) { return NGX_OK; } if (c->write->delayed) { c->buffered |= NGX_HTTP_WRITE_BUFFERED; return NGX_AGAIN; } if (size == 0 && !(c->buffered & NGX_LOWLEVEL_BUFFERED) && !(last && c->need_last_buf)) { if (last || flush || sync) { for (cl = r->out; cl; /* void */) { ln = cl; cl = cl->next; ngx_free_chain(r->pool, ln); } r->out = NULL; c->buffered &= ~NGX_HTTP_WRITE_BUFFERED; return NGX_OK; } ngx_log_error(NGX_LOG_ALERT, c->log, 0, "the http output chain is empty"); ngx_debug_point(); return NGX_ERROR; } if (!r->limit_rate_set) { r->limit_rate = ngx_http_complex_value_size(r, clcf->limit_rate, 0); r->limit_rate_set = 1; } if (r->limit_rate) { if (!r->limit_rate_after_set) { r->limit_rate_after = ngx_http_complex_value_size(r, clcf->limit_rate_after, 0); r->limit_rate_after_set = 1; } limit = (off_t) r->limit_rate * (ngx_time() - r->start_sec + 1) - (c->sent - r->limit_rate_after); if (limit <= 0) { c->write->delayed = 1; delay = (ngx_msec_t) (- limit * 1000 / r->limit_rate + 1); ngx_add_timer(c->write, delay); c->buffered |= NGX_HTTP_WRITE_BUFFERED; return NGX_AGAIN; } if (clcf->sendfile_max_chunk && (off_t) clcf->sendfile_max_chunk < limit) { limit = clcf->sendfile_max_chunk; } } else { limit = clcf->sendfile_max_chunk; } sent = c->sent; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http write filter limit %O", limit); chain = c->send_chain(c, r->out, limit); ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http write filter %p", chain); if (chain == NGX_CHAIN_ERROR) { c->error = 1; return NGX_ERROR; } if (r->limit_rate) { nsent = c->sent; if (r->limit_rate_after) { sent -= r->limit_rate_after; if (sent < 0) { sent = 0; } nsent -= r->limit_rate_after; if (nsent < 0) { nsent = 0; } } delay = (ngx_msec_t) ((nsent - sent) * 1000 / r->limit_rate); if (delay > 0) { c->write->delayed = 1; ngx_add_timer(c->write, delay); } } if (chain && c->write->ready && !c->write->delayed) { ngx_post_event(c->write, &ngx_posted_next_events); } for (cl = r->out; cl && cl != chain; /* void */) { ln = cl; cl = cl->next; ngx_free_chain(r->pool, ln); } r->out = chain; if (chain) { c->buffered |= NGX_HTTP_WRITE_BUFFERED; return NGX_AGAIN; } c->buffered &= ~NGX_HTTP_WRITE_BUFFERED; if ((c->buffered & NGX_LOWLEVEL_BUFFERED) && r->postponed == NULL) { return NGX_AGAIN; } return NGX_OK; } static ngx_int_t ngx_http_write_filter_init(ngx_conf_t *cf) { ngx_http_top_body_filter = ngx_http_write_filter; return NGX_OK; }