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Revision 0baca070068c58b95e342881d9da4840d5cf3bd1 authored by Linus Torvalds on 22 September 2020, 21:36:50 UTC, committed by Linus Torvalds on 22 September 2020, 21:36:50 UTC 
Merge tag 'io_uring-5.9-2020-09-22' of git://git.kernel.dk/linux-block
 
Pull io_uring fixes from Jens Axboe:
 "A few fixes - most of them regression fixes from this cycle, but also
  a few stable heading fixes, and a build fix for the included demo tool
  since some systems now actually have gettid() available"

* tag 'io_uring-5.9-2020-09-22' of git://git.kernel.dk/linux-block:
  io_uring: fix openat/openat2 unified prep handling
  io_uring: mark statx/files_update/epoll_ctl as non-SQPOLL
  tools/io_uring: fix compile breakage
  io_uring: don't use retry based buffered reads for non-async bdev
  io_uring: don't re-setup vecs/iter in io_resumit_prep() is already there
  io_uring: don't run task work on an exiting task
  io_uring: drop 'ctx' ref on task work cancelation
  io_uring: grab any needed state during defer prep
2 parent s c37b718 + 4eb8dde
Raw File
tcp_scalable.c 
// SPDX-License-Identifier: GPL-2.0-only
/* Tom Kelly's Scalable TCP
 *
 * See http://www.deneholme.net/tom/scalable/
 *
 * John Heffner <jheffner@sc.edu>
 */

#include <linux/module.h>
#include <net/tcp.h>

/* These factors derived from the recommended values in the aer:
 * .01 and and 7/8.
 */
#define TCP_SCALABLE_AI_CNT	100U
#define TCP_SCALABLE_MD_SCALE	3

static void tcp_scalable_cong_avoid(struct sock *sk, u32 ack, u32 acked)
{
	struct tcp_sock *tp = tcp_sk(sk);

	if (!tcp_is_cwnd_limited(sk))
		return;

	if (tcp_in_slow_start(tp)) {
		acked = tcp_slow_start(tp, acked);
		if (!acked)
			return;
	}
	tcp_cong_avoid_ai(tp, min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT),
			  acked);
}

static u32 tcp_scalable_ssthresh(struct sock *sk)
{
	const struct tcp_sock *tp = tcp_sk(sk);

	return max(tp->snd_cwnd - (tp->snd_cwnd>>TCP_SCALABLE_MD_SCALE), 2U);
}

static struct tcp_congestion_ops tcp_scalable __read_mostly = {
	.ssthresh	= tcp_scalable_ssthresh,
	.undo_cwnd	= tcp_reno_undo_cwnd,
	.cong_avoid	= tcp_scalable_cong_avoid,

	.owner		= THIS_MODULE,
	.name		= "scalable",
};

static int __init tcp_scalable_register(void)
{
	return tcp_register_congestion_control(&tcp_scalable);
}

static void __exit tcp_scalable_unregister(void)
{
	tcp_unregister_congestion_control(&tcp_scalable);
}

module_init(tcp_scalable_register);
module_exit(tcp_scalable_unregister);

MODULE_AUTHOR("John Heffner");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Scalable TCP");
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