diff options
| -rw-r--r-- | src/include/ipxe/peerblk.h | 24 | ||||
| -rw-r--r-- | src/net/peerblk.c | 134 |
2 files changed, 155 insertions, 3 deletions
diff --git a/src/include/ipxe/peerblk.h b/src/include/ipxe/peerblk.h index 6fc9172f..f16f207b 100644 --- a/src/include/ipxe/peerblk.h +++ b/src/include/ipxe/peerblk.h @@ -111,6 +111,10 @@ struct peerdist_block { struct peerdisc_client discovery; /** Current position in discovered peer list */ struct peerdisc_peer *peer; + /** Block download queue */ + struct peerdist_block_queue *queue; + /** List of queued block downloads */ + struct list_head queued; /** Retry timer */ struct retry_timer timer; /** Number of full attempt cycles completed */ @@ -124,6 +128,26 @@ struct peerdist_block { unsigned long attempted; }; +/** PeerDist block download queue */ +struct peerdist_block_queue { + /** Download opening process */ + struct process process; + /** List of queued downloads */ + struct list_head list; + + /** Number of open downloads */ + unsigned int count; + /** Maximum number of open downloads */ + unsigned int max; + + /** Open block download + * + * @v peerblk PeerDist block download + * @ret rc Return status code + */ + int ( * open ) ( struct peerdist_block *peerblk ); +}; + /** Retrieval protocol block fetch response (including transport header) * * @v digestsize Digest size diff --git a/src/net/peerblk.c b/src/net/peerblk.c index 27184e2d..f8994f42 100644 --- a/src/net/peerblk.c +++ b/src/net/peerblk.c @@ -48,6 +48,25 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); */ #define PEERBLK_DECRYPT_CHUNKSIZE 2048 +/** PeerDist maximum number of concurrent raw block downloads + * + * Raw block downloads are expensive if the origin server uses HTTPS, + * since each concurrent download will require local TLS resources + * (including potentially large received encrypted data buffers). + * + * Raw block downloads may also be prohibitively slow to initiate when + * the origin server is using HTTPS and client certificates. Origin + * servers for PeerDist downloads are likely to be running IIS, which + * has a bug that breaks session resumption and requires each + * connection to go through the full client certificate verification. + * + * Limit the total number of concurrent raw block downloads to + * ameliorate these problems. + * + * This is a policy decision. + */ +#define PEERBLK_RAW_MAX 2 + /** PeerDist raw block download attempt initial progress timeout * * This is a policy decision. @@ -107,6 +126,8 @@ static struct profiler peerblk_discovery_success_profiler __profiler = static struct profiler peerblk_discovery_timeout_profiler __profiler = { .name = "peerblk.discovery.timeout" }; +static void peerblk_dequeue ( struct peerdist_block *peerblk ); + /** * Get profiling timestamp * @@ -154,6 +175,10 @@ static void peerblk_reset ( struct peerdist_block *peerblk, int rc ) { intf_restart ( &peerblk->raw, rc ); intf_restart ( &peerblk->retrieval, rc ); + /* Remove from download queue, if applicable */ + if ( peerblk->queue ) + peerblk_dequeue ( peerblk ); + /* Empty received data buffer */ xferbuf_free ( &peerblk->buffer ); peerblk->pos = 0; @@ -441,6 +466,109 @@ static void peerblk_raw_close ( struct peerdist_block *peerblk, int rc ) { /****************************************************************************** * + * Block download queue + * + ****************************************************************************** + */ + +/** + * PeerDist block download queue process + * + * @v queue Block download queue + */ +static void peerblk_step ( struct peerdist_block_queue *queue ) { + struct peerdist_block *peerblk; + int rc; + + /* Do nothing yet if we have too many open block downloads */ + if ( queue->count >= queue->max ) + return; + + /* Do nothing unless there are queued block downloads */ + peerblk = list_first_entry ( &queue->list, struct peerdist_block, + queued ); + if ( ! peerblk ) + return; + + /* Reschedule queue process */ + process_add ( &queue->process ); + + /* Remove block from queue */ + list_del ( &peerblk->queued ); + INIT_LIST_HEAD ( &peerblk->queued ); + + /* Attempt download */ + if ( ( rc = queue->open ( peerblk ) ) != 0 ) { + peerblk_close ( peerblk, rc ); + return; + } + + /* Increment open block download count */ + queue->count++; +} + +/** + * Add block to download queue + * + * @v peerblk PeerDist block download + * @v queue Block download queue + */ +static void peerblk_enqueue ( struct peerdist_block *peerblk, + struct peerdist_block_queue *queue ) { + + /* Sanity checks */ + assert ( peerblk->queue == NULL ); + assert ( list_empty ( &peerblk->queued ) ); + + /* Add block to queue */ + peerblk->queue = queue; + list_add_tail ( &peerblk->queued, &queue->list ); + + /* Schedule queue process */ + process_add ( &queue->process ); +} + +/** + * Remove block from download queue + * + * @v peerblk PeerDist block download + */ +static void peerblk_dequeue ( struct peerdist_block *peerblk ) { + struct peerdist_block_queue *queue = peerblk->queue; + + /* Sanity checks */ + assert ( queue != NULL ); + + /* Remove block from queue */ + peerblk->queue = NULL; + if ( list_empty ( &peerblk->queued ) ) { + + /* Open download: decrement count and reschedule queue */ + queue->count--; + process_add ( &queue->process ); + + } else { + + /* Queued download: remove from queue */ + list_del ( &peerblk->queued ); + INIT_LIST_HEAD ( &peerblk->queued ); + } +} + +/** PeerDist block download queue process descriptor */ +static struct process_descriptor peerblk_queue_desc = + PROC_DESC_ONCE ( struct peerdist_block_queue, process, peerblk_step ); + +/** Raw block download queue */ +static struct peerdist_block_queue peerblk_raw_queue = { + .process = PROC_INIT ( peerblk_raw_queue.process, &peerblk_queue_desc ), + .list = LIST_HEAD_INIT ( peerblk_raw_queue.list ), + .max = PEERBLK_RAW_MAX, + .open = peerblk_raw_open, +}; + +/****************************************************************************** + * * Retrieval protocol block download attempts (using HTTP POST) * ****************************************************************************** @@ -1213,9 +1341,8 @@ static void peerblk_expired ( struct retry_timer *timer, int over __unused ) { return; } - /* Attempt raw download */ - if ( ( rc = peerblk_raw_open ( peerblk ) ) != 0 ) - goto err; + /* Add to raw download queue */ + peerblk_enqueue ( peerblk, &peerblk_raw_queue ); return; @@ -1338,6 +1465,7 @@ int peerblk_open ( struct interface *xfer, struct uri *uri, process_init_stopped ( &peerblk->process, &peerblk_process_desc, &peerblk->refcnt ); peerdisc_init ( &peerblk->discovery, &peerblk_discovery_operations ); + INIT_LIST_HEAD ( &peerblk->queued ); timer_init ( &peerblk->timer, peerblk_expired, &peerblk->refcnt ); DBGC2 ( peerblk, "PEERBLK %p %d.%d id %02x%02x%02x%02x%02x..." "%02x%02x%02x [%08zx,%08zx)", peerblk, peerblk->segment, |