Mercurial > hg > nginx
changeset 8946:56dec0d4e5b1 quic
QUIC: avoid excessive buffer allocations in stream output.
Previously, when a few bytes were send to a QUIC stream by the application, a
4K buffer was allocated for these bytes. Then a STREAM frame was created and
that entire buffer was used as data for that frame. The frame with the buffer
were in use up until the frame was acked by client. Meanwhile, when more
bytes were send to the stream, more buffers were allocated and assigned as
data to newer STREAM frames. In this scenario most buffer memory is unused.
Now the unused part of the stream output buffer is available for further
stream output while earlier parts of the buffer are waiting to be acked.
This is achieved by splitting the output buffer.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Fri, 24 Dec 2021 18:13:51 +0300 |
parents | e72db9162180 |
children | 6ccf3867959a |
files | src/event/quic/ngx_event_quic.h src/event/quic/ngx_event_quic_frames.c src/event/quic/ngx_event_quic_frames.h src/event/quic/ngx_event_quic_ssl.c src/event/quic/ngx_event_quic_streams.c |
diffstat | 5 files changed, 33 insertions(+), 15 deletions(-) [+] |
line wrap: on
line diff
--- a/src/event/quic/ngx_event_quic.h Mon Dec 27 13:52:57 2021 +0300 +++ b/src/event/quic/ngx_event_quic.h Fri Dec 24 18:13:51 2021 +0300 @@ -63,6 +63,7 @@ uint64_t recv_last; uint64_t final_size; ngx_chain_t *in; + ngx_chain_t *out; ngx_uint_t cancelable; /* unsigned cancelable:1; */ };
--- a/src/event/quic/ngx_event_quic_frames.c Mon Dec 27 13:52:57 2021 +0300 +++ b/src/event/quic/ngx_event_quic_frames.c Fri Dec 24 18:13:51 2021 +0300 @@ -482,14 +482,14 @@ ngx_int_t ngx_quic_order_bufs(ngx_connection_t *c, ngx_chain_t **out, ngx_chain_t *in, - size_t offset) + off_t limit, off_t offset) { + off_t n; u_char *p; - size_t n; ngx_buf_t *b; ngx_chain_t *cl, *sl; - while (in) { + while (in && limit) { cl = *out; if (cl == NULL) { @@ -523,8 +523,9 @@ continue; } - for (p = b->pos + offset; p != b->last && in; /* void */ ) { + for (p = b->pos + offset; p != b->last && in && limit; /* void */ ) { n = ngx_min(b->last - p, in->buf->last - in->buf->pos); + n = ngx_min(n, limit); if (b->sync) { ngx_memcpy(p, in->buf->pos, n); @@ -533,6 +534,7 @@ p += n; in->buf->pos += n; offset += n; + limit -= n; if (in->buf->pos == in->buf->last) { in = in->next;
--- a/src/event/quic/ngx_event_quic_frames.h Mon Dec 27 13:52:57 2021 +0300 +++ b/src/event/quic/ngx_event_quic_frames.h Fri Dec 24 18:13:51 2021 +0300 @@ -31,7 +31,7 @@ void ngx_quic_trim_bufs(ngx_chain_t *in, size_t size); void ngx_quic_free_bufs(ngx_connection_t *c, ngx_chain_t *in); ngx_int_t ngx_quic_order_bufs(ngx_connection_t *c, ngx_chain_t **out, - ngx_chain_t *in, size_t offset); + ngx_chain_t *in, off_t limit, off_t offset); #if (NGX_DEBUG) void ngx_quic_log_frame(ngx_log_t *log, ngx_quic_frame_t *f, ngx_uint_t tx);
--- a/src/event/quic/ngx_event_quic_ssl.c Mon Dec 27 13:52:57 2021 +0300 +++ b/src/event/quic/ngx_event_quic_ssl.c Fri Dec 24 18:13:51 2021 +0300 @@ -369,7 +369,7 @@ } if (f->offset > ctx->crypto_received) { - return ngx_quic_order_bufs(c, &ctx->crypto, frame->data, + return ngx_quic_order_bufs(c, &ctx->crypto, frame->data, f->length, f->offset - ctx->crypto_received); }
--- a/src/event/quic/ngx_event_quic_streams.c Mon Dec 27 13:52:57 2021 +0300 +++ b/src/event/quic/ngx_event_quic_streams.c Fri Dec 24 18:13:51 2021 +0300 @@ -838,8 +838,9 @@ ngx_quic_stream_send_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit) { size_t n, flow; + ngx_buf_t *b; ngx_event_t *wev; - ngx_chain_t *cl; + ngx_chain_t *out, **ll; ngx_connection_t *pc; ngx_quic_frame_t *frame; ngx_quic_stream_t *qs; @@ -862,18 +863,30 @@ n = (limit && (size_t) limit < flow) ? (size_t) limit : flow; - frame = ngx_quic_alloc_frame(pc); - if (frame == NULL) { + if (ngx_quic_order_bufs(pc, &qs->out, in, n, 0) != NGX_OK) { return NGX_CHAIN_ERROR; } - frame->data = ngx_quic_copy_chain(pc, in, n); - if (frame->data == NGX_CHAIN_ERROR) { - return NGX_CHAIN_ERROR; + n = 0; + out = qs->out; + + for (ll = &out; *ll; ll = &(*ll)->next) { + b = (*ll)->buf; + + if (b->sync) { + /* hole */ + break; + } + + n += b->last - b->pos; } - for (n = 0, cl = frame->data; cl; cl = cl->next) { - n += ngx_buf_size(cl->buf); + qs->out = *ll; + *ll = NULL; + + frame = ngx_quic_alloc_frame(pc); + if (frame == NULL) { + return NGX_CHAIN_ERROR; } while (in && ngx_buf_size(in->buf) == 0) { @@ -882,6 +895,7 @@ frame->level = ssl_encryption_application; frame->type = NGX_QUIC_FT_STREAM; + frame->data = out; frame->u.stream.off = 1; frame->u.stream.len = 1; frame->u.stream.fin = 0; @@ -977,6 +991,7 @@ ngx_rbtree_delete(&qc->streams.tree, &qs->node); ngx_quic_free_bufs(pc, qs->in); + ngx_quic_free_bufs(pc, qs->out); if (qc->closing) { /* schedule handler call to continue ngx_quic_close_connection() */ @@ -1098,7 +1113,7 @@ qs->final_size = last; } - if (ngx_quic_order_bufs(c, &qs->in, frame->data, + if (ngx_quic_order_bufs(c, &qs->in, frame->data, f->length, f->offset - qs->recv_offset) != NGX_OK) {