Mercurial > hg > nginx-quic
view src/os/unix/ngx_aio_read_chain.c @ 5718:c46657e391a3
Core: slab allocator free pages defragmentation.
Large allocations from a slab pool result in free page blocks being fragmented,
eventually leading to a situation when no further allocation larger than a page
size are possible from the pool. While this isn't a problem for nginx itself,
it is known to be bad for various 3rd party modules. Fix is to merge adjacent
blocks of free pages in the ngx_slab_free_pages() function.
Prodded by Wandenberg Peixoto and Yichun Zhang.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Tue, 03 Jun 2014 17:53:03 +0400 |
parents | d620f497c50f |
children | ec81934727a1 |
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> ssize_t ngx_aio_read_chain(ngx_connection_t *c, ngx_chain_t *cl) { int n; u_char *buf, *prev; size_t size; ssize_t total; if (c->read->pending_eof) { c->read->ready = 0; return 0; } total = 0; while (cl) { /* we can post the single aio operation only */ if (!c->read->ready) { return total ? total : NGX_AGAIN; } buf = cl->buf->last; prev = cl->buf->last; size = 0; /* coalesce the neighbouring bufs */ while (cl && prev == cl->buf->last) { size += cl->buf->end - cl->buf->last; prev = cl->buf->end; cl = cl->next; } n = ngx_aio_read(c, buf, size); ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "aio_read: %d", n); if (n == NGX_AGAIN) { return total ? total : NGX_AGAIN; } if (n == NGX_ERROR) { return NGX_ERROR; } if (n == 0) { c->read->pending_eof = 1; if (total) { c->read->eof = 0; c->read->ready = 1; } return total; } if (n > 0) { total += n; } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "aio_read total: %d", total); } return total ? total : NGX_AGAIN; }