view src/os/unix/ngx_writev_chain.c @ 5822:063f7e75f9ef

Upstream: suppressed the file cache slab allocator error messages. The messages "ngx_slab_alloc() failed: no memory in cache keys zone" from the file cache slab allocator are suppressed since the allocation is likely to succeed after the forced expiration of cache nodes. The second allocation failure is reported.
author Roman Arutyunyan <arut@nginx.com>
date Fri, 05 Sep 2014 18:14:59 +0400
parents 089cc5154c1e
children f9c83484d9ce
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>


#if (IOV_MAX > 64)
#define NGX_IOVS  64
#else
#define NGX_IOVS  IOV_MAX
#endif


ngx_chain_t *
ngx_writev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
{
    u_char        *prev;
    ssize_t        n, size, sent;
    off_t          send, prev_send;
    ngx_uint_t     eintr, complete;
    ngx_err_t      err;
    ngx_array_t    vec;
    ngx_chain_t   *cl;
    ngx_event_t   *wev;
    struct iovec  *iov, iovs[NGX_IOVS];

    wev = c->write;

    if (!wev->ready) {
        return in;
    }

#if (NGX_HAVE_KQUEUE)

    if ((ngx_event_flags & NGX_USE_KQUEUE_EVENT) && wev->pending_eof) {
        (void) ngx_connection_error(c, wev->kq_errno,
                               "kevent() reported about an closed connection");
        wev->error = 1;
        return NGX_CHAIN_ERROR;
    }

#endif

    /* the maximum limit size is the maximum size_t value - the page size */

    if (limit == 0 || limit > (off_t) (NGX_MAX_SIZE_T_VALUE - ngx_pagesize)) {
        limit = NGX_MAX_SIZE_T_VALUE - ngx_pagesize;
    }

    send = 0;

    vec.elts = iovs;
    vec.size = sizeof(struct iovec);
    vec.nalloc = NGX_IOVS;
    vec.pool = c->pool;

    for ( ;; ) {
        prev = NULL;
        iov = NULL;
        eintr = 0;
        complete = 0;
        prev_send = send;

        vec.nelts = 0;

        /* create the iovec and coalesce the neighbouring bufs */

        for (cl = in; cl && send < limit; cl = cl->next) {

            if (ngx_buf_special(cl->buf)) {
                continue;
            }

#if 1
            if (!ngx_buf_in_memory(cl->buf)) {
                ngx_debug_point();
            }
#endif

            size = cl->buf->last - cl->buf->pos;

            if (send + size > limit) {
                size = (ssize_t) (limit - send);
            }

            if (prev == cl->buf->pos) {
                iov->iov_len += size;

            } else {
                if (vec.nelts >= IOV_MAX) {
                    break;
                }

                iov = ngx_array_push(&vec);
                if (iov == NULL) {
                    return NGX_CHAIN_ERROR;
                }

                iov->iov_base = (void *) cl->buf->pos;
                iov->iov_len = size;
            }

            prev = cl->buf->pos + size;
            send += size;
        }

        n = writev(c->fd, vec.elts, vec.nelts);

        if (n == -1) {
            err = ngx_errno;

            switch (err) {
            case NGX_EAGAIN:
                break;

            case NGX_EINTR:
                eintr = 1;
                break;

            default:
                wev->error = 1;
                (void) ngx_connection_error(c, err, "writev() failed");
                return NGX_CHAIN_ERROR;
            }

            ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err,
                           "writev() not ready");
        }

        sent = n > 0 ? n : 0;

        ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "writev: %z", sent);

        if (send - prev_send == sent) {
            complete = 1;
        }

        c->sent += sent;

        for (cl = in; cl; cl = cl->next) {

            if (ngx_buf_special(cl->buf)) {
                continue;
            }

            if (sent == 0) {
                break;
            }

            size = cl->buf->last - cl->buf->pos;

            if (sent >= size) {
                sent -= size;
                cl->buf->pos = cl->buf->last;

                continue;
            }

            cl->buf->pos += sent;

            break;
        }

        if (eintr) {
            continue;
        }

        if (!complete) {
            wev->ready = 0;
            return cl;
        }

        if (send >= limit || cl == NULL) {
            return cl;
        }

        in = cl;
    }
}