diff options
author | Stephen Rothwell <sfr@canb.auug.org.au> | 2009-03-02 17:56:48 +1100 |
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committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2009-03-02 17:56:48 +1100 |
commit | a50c0bd33e82268fac30fd5e51bbe0bc7800bba2 (patch) | |
tree | 1d01fbd8f864e6da5520bdaee32a6c837d266292 | |
parent | 3ae24edc5bf630157e3701fc3534a2893c9f2247 (diff) |
Revert "RDS: Congestion-handling code"
This reverts commit 922cb17a5c812fcc9ebee249f4109db099896941.
-rw-r--r-- | net/rds/cong.c | 402 |
1 files changed, 0 insertions, 402 deletions
diff --git a/net/rds/cong.c b/net/rds/cong.c deleted file mode 100644 index 90e6b31d8e8a..000000000000 --- a/net/rds/cong.c +++ /dev/null @@ -1,402 +0,0 @@ -/* - * Copyright (c) 2007 Oracle. All rights reserved. - * - * This software is available to you under a choice of one of two - * licenses. You may choose to be licensed under the terms of the GNU - * General Public License (GPL) Version 2, available from the file - * COPYING in the main directory of this source tree, or the - * OpenIB.org BSD license below: - * - * Redistribution and use in source and binary forms, with or - * without modification, are permitted provided that the following - * conditions are met: - * - * - Redistributions of source code must retain the above - * copyright notice, this list of conditions and the following - * disclaimer. - * - * - Redistributions in binary form must reproduce the above - * copyright notice, this list of conditions and the following - * disclaimer in the documentation and/or other materials - * provided with the distribution. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, - * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF - * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND - * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS - * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN - * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN - * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE - * SOFTWARE. - * - */ -#include <linux/types.h> -#include <linux/rbtree.h> - -#include "rds.h" - -/* - * This file implements the receive side of the unconventional congestion - * management in RDS. - * - * Messages waiting in the receive queue on the receiving socket are accounted - * against the sockets SO_RCVBUF option value. Only the payload bytes in the - * message are accounted for. If the number of bytes queued equals or exceeds - * rcvbuf then the socket is congested. All sends attempted to this socket's - * address should return block or return -EWOULDBLOCK. - * - * Applications are expected to be reasonably tuned such that this situation - * very rarely occurs. An application encountering this "back-pressure" is - * considered a bug. - * - * This is implemented by having each node maintain bitmaps which indicate - * which ports on bound addresses are congested. As the bitmap changes it is - * sent through all the connections which terminate in the local address of the - * bitmap which changed. - * - * The bitmaps are allocated as connections are brought up. This avoids - * allocation in the interrupt handling path which queues messages on sockets. - * The dense bitmaps let transports send the entire bitmap on any bitmap change - * reasonably efficiently. This is much easier to implement than some - * finer-grained communication of per-port congestion. The sender does a very - * inexpensive bit test to test if the port it's about to send to is congested - * or not. - */ - -/* - * Interaction with poll is a tad tricky. We want all processes stuck in - * poll to wake up and check whether a congested destination became uncongested. - * The really sad thing is we have no idea which destinations the application - * wants to send to - we don't even know which rds_connections are involved. - * So until we implement a more flexible rds poll interface, we have to make - * do with this: - * We maintain a global counter that is incremented each time a congestion map - * update is received. Each rds socket tracks this value, and if rds_poll - * finds that the saved generation number is smaller than the global generation - * number, it wakes up the process. - */ -static atomic_t rds_cong_generation = ATOMIC_INIT(0); - -/* - * Congestion monitoring - */ -static LIST_HEAD(rds_cong_monitor); -static DEFINE_RWLOCK(rds_cong_monitor_lock); - -/* - * Yes, a global lock. It's used so infrequently that it's worth keeping it - * global to simplify the locking. It's only used in the following - * circumstances: - * - * - on connection buildup to associate a conn with its maps - * - on map changes to inform conns of a new map to send - * - * It's sadly ordered under the socket callback lock and the connection lock. - * Receive paths can mark ports congested from interrupt context so the - * lock masks interrupts. - */ -static DEFINE_SPINLOCK(rds_cong_lock); -static struct rb_root rds_cong_tree = RB_ROOT; - -static struct rds_cong_map *rds_cong_tree_walk(__be32 addr, - struct rds_cong_map *insert) -{ - struct rb_node **p = &rds_cong_tree.rb_node; - struct rb_node *parent = NULL; - struct rds_cong_map *map; - - while (*p) { - parent = *p; - map = rb_entry(parent, struct rds_cong_map, m_rb_node); - - if (addr < map->m_addr) - p = &(*p)->rb_left; - else if (addr > map->m_addr) - p = &(*p)->rb_right; - else - return map; - } - - if (insert) { - rb_link_node(&insert->m_rb_node, parent, p); - rb_insert_color(&insert->m_rb_node, &rds_cong_tree); - } - return NULL; -} - -/* - * There is only ever one bitmap for any address. Connections try and allocate - * these bitmaps in the process getting pointers to them. The bitmaps are only - * ever freed as the module is removed after all connections have been freed. - */ -static struct rds_cong_map *rds_cong_from_addr(__be32 addr) -{ - struct rds_cong_map *map; - struct rds_cong_map *ret = NULL; - unsigned long zp; - unsigned long i; - unsigned long flags; - - map = kzalloc(sizeof(struct rds_cong_map), GFP_KERNEL); - if (map == NULL) - return NULL; - - map->m_addr = addr; - init_waitqueue_head(&map->m_waitq); - INIT_LIST_HEAD(&map->m_conn_list); - - for (i = 0; i < RDS_CONG_MAP_PAGES; i++) { - zp = get_zeroed_page(GFP_KERNEL); - if (zp == 0) - goto out; - map->m_page_addrs[i] = zp; - } - - spin_lock_irqsave(&rds_cong_lock, flags); - ret = rds_cong_tree_walk(addr, map); - spin_unlock_irqrestore(&rds_cong_lock, flags); - - if (ret == NULL) { - ret = map; - map = NULL; - } - -out: - if (map) { - for (i = 0; i < RDS_CONG_MAP_PAGES && map->m_page_addrs[i]; i++) - free_page(map->m_page_addrs[i]); - kfree(map); - } - - rdsdebug("map %p for addr %x\n", ret, be32_to_cpu(addr)); - - return ret; -} - -/* - * Put the conn on its local map's list. This is called when the conn is - * really added to the hash. It's nested under the rds_conn_lock, sadly. - */ -void rds_cong_add_conn(struct rds_connection *conn) -{ - unsigned long flags; - - rdsdebug("conn %p now on map %p\n", conn, conn->c_lcong); - spin_lock_irqsave(&rds_cong_lock, flags); - list_add_tail(&conn->c_map_item, &conn->c_lcong->m_conn_list); - spin_unlock_irqrestore(&rds_cong_lock, flags); -} - -void rds_cong_remove_conn(struct rds_connection *conn) -{ - unsigned long flags; - - rdsdebug("removing conn %p from map %p\n", conn, conn->c_lcong); - spin_lock_irqsave(&rds_cong_lock, flags); - list_del_init(&conn->c_map_item); - spin_unlock_irqrestore(&rds_cong_lock, flags); -} - -int rds_cong_get_maps(struct rds_connection *conn) -{ - conn->c_lcong = rds_cong_from_addr(conn->c_laddr); - conn->c_fcong = rds_cong_from_addr(conn->c_faddr); - - if (conn->c_lcong == NULL || conn->c_fcong == NULL) - return -ENOMEM; - - return 0; -} - -void rds_cong_queue_updates(struct rds_cong_map *map) -{ - struct rds_connection *conn; - unsigned long flags; - - spin_lock_irqsave(&rds_cong_lock, flags); - - list_for_each_entry(conn, &map->m_conn_list, c_map_item) { - if (!test_and_set_bit(0, &conn->c_map_queued)) { - rds_stats_inc(s_cong_update_queued); - queue_delayed_work(rds_wq, &conn->c_send_w, 0); - } - } - - spin_unlock_irqrestore(&rds_cong_lock, flags); -} - -void rds_cong_map_updated(struct rds_cong_map *map, uint64_t portmask) -{ - rdsdebug("waking map %p for %pI4\n", - map, &map->m_addr); - rds_stats_inc(s_cong_update_received); - atomic_inc(&rds_cong_generation); - if (waitqueue_active(&map->m_waitq)) - wake_up(&map->m_waitq); - if (waitqueue_active(&rds_poll_waitq)) - wake_up_all(&rds_poll_waitq); - - if (portmask && !list_empty(&rds_cong_monitor)) { - unsigned long flags; - struct rds_sock *rs; - - read_lock_irqsave(&rds_cong_monitor_lock, flags); - list_for_each_entry(rs, &rds_cong_monitor, rs_cong_list) { - spin_lock(&rs->rs_lock); - rs->rs_cong_notify |= (rs->rs_cong_mask & portmask); - rs->rs_cong_mask &= ~portmask; - spin_unlock(&rs->rs_lock); - if (rs->rs_cong_notify) - rds_wake_sk_sleep(rs); - } - read_unlock_irqrestore(&rds_cong_monitor_lock, flags); - } -} - -int rds_cong_updated_since(unsigned long *recent) -{ - unsigned long gen = atomic_read(&rds_cong_generation); - - if (likely(*recent == gen)) - return 0; - *recent = gen; - return 1; -} - -/* - * We're called under the locking that protects the sockets receive buffer - * consumption. This makes it a lot easier for the caller to only call us - * when it knows that an existing set bit needs to be cleared, and vice versa. - * We can't block and we need to deal with concurrent sockets working against - * the same per-address map. - */ -void rds_cong_set_bit(struct rds_cong_map *map, __be16 port) -{ - unsigned long i; - unsigned long off; - - rdsdebug("setting congestion for %pI4:%u in map %p\n", - &map->m_addr, ntohs(port), map); - - i = be16_to_cpu(port) / RDS_CONG_MAP_PAGE_BITS; - off = be16_to_cpu(port) % RDS_CONG_MAP_PAGE_BITS; - - generic___set_le_bit(off, (void *)map->m_page_addrs[i]); -} - -void rds_cong_clear_bit(struct rds_cong_map *map, __be16 port) -{ - unsigned long i; - unsigned long off; - - rdsdebug("clearing congestion for %pI4:%u in map %p\n", - &map->m_addr, ntohs(port), map); - - i = be16_to_cpu(port) / RDS_CONG_MAP_PAGE_BITS; - off = be16_to_cpu(port) % RDS_CONG_MAP_PAGE_BITS; - - generic___clear_le_bit(off, (void *)map->m_page_addrs[i]); -} - -static int rds_cong_test_bit(struct rds_cong_map *map, __be16 port) -{ - unsigned long i; - unsigned long off; - - i = be16_to_cpu(port) / RDS_CONG_MAP_PAGE_BITS; - off = be16_to_cpu(port) % RDS_CONG_MAP_PAGE_BITS; - - return generic_test_le_bit(off, (void *)map->m_page_addrs[i]); -} - -void rds_cong_add_socket(struct rds_sock *rs) -{ - unsigned long flags; - - write_lock_irqsave(&rds_cong_monitor_lock, flags); - if (list_empty(&rs->rs_cong_list)) - list_add(&rs->rs_cong_list, &rds_cong_monitor); - write_unlock_irqrestore(&rds_cong_monitor_lock, flags); -} - -void rds_cong_remove_socket(struct rds_sock *rs) -{ - unsigned long flags; - struct rds_cong_map *map; - - write_lock_irqsave(&rds_cong_monitor_lock, flags); - list_del_init(&rs->rs_cong_list); - write_unlock_irqrestore(&rds_cong_monitor_lock, flags); - - /* update congestion map for now-closed port */ - spin_lock_irqsave(&rds_cong_lock, flags); - map = rds_cong_tree_walk(rs->rs_bound_addr, NULL); - spin_unlock_irqrestore(&rds_cong_lock, flags); - - if (map && rds_cong_test_bit(map, rs->rs_bound_port)) { - rds_cong_clear_bit(map, rs->rs_bound_port); - rds_cong_queue_updates(map); - } -} - -int rds_cong_wait(struct rds_cong_map *map, __be16 port, int nonblock, - struct rds_sock *rs) -{ - if (!rds_cong_test_bit(map, port)) - return 0; - if (nonblock) { - if (rs && rs->rs_cong_monitor) { - unsigned long flags; - - /* It would have been nice to have an atomic set_bit on - * a uint64_t. */ - spin_lock_irqsave(&rs->rs_lock, flags); - rs->rs_cong_mask |= RDS_CONG_MONITOR_MASK(ntohs(port)); - spin_unlock_irqrestore(&rs->rs_lock, flags); - - /* Test again - a congestion update may have arrived in - * the meantime. */ - if (!rds_cong_test_bit(map, port)) - return 0; - } - rds_stats_inc(s_cong_send_error); - return -ENOBUFS; - } - - rds_stats_inc(s_cong_send_blocked); - rdsdebug("waiting on map %p for port %u\n", map, be16_to_cpu(port)); - - return wait_event_interruptible(map->m_waitq, - !rds_cong_test_bit(map, port)); -} - -void rds_cong_exit(void) -{ - struct rb_node *node; - struct rds_cong_map *map; - unsigned long i; - - while ((node = rb_first(&rds_cong_tree))) { - map = rb_entry(node, struct rds_cong_map, m_rb_node); - rdsdebug("freeing map %p\n", map); - rb_erase(&map->m_rb_node, &rds_cong_tree); - for (i = 0; i < RDS_CONG_MAP_PAGES && map->m_page_addrs[i]; i++) - free_page(map->m_page_addrs[i]); - kfree(map); - } -} - -/* - * Allocate a RDS message containing a congestion update. - */ -struct rds_message *rds_cong_update_alloc(struct rds_connection *conn) -{ - struct rds_cong_map *map = conn->c_lcong; - struct rds_message *rm; - - rm = rds_message_map_pages(map->m_page_addrs, RDS_CONG_MAP_BYTES); - if (!IS_ERR(rm)) - rm->m_inc.i_hdr.h_flags = RDS_FLAG_CONG_BITMAP; - - return rm; -} |