/*
 * linux/net/sunrpc/timer.c
 *
 * Estimate RPC request round trip time.
 *
 * Based on packet round-trip and variance estimator algorithms described
 * in appendix A of "Congestion Avoidance and Control" by Van Jacobson
 * and Michael J. Karels (ACM Computer Communication Review; Proceedings
 * of the Sigcomm '88 Symposium in Stanford, CA, August, 1988).
 *
 * This RTT estimator is used only for RPC over datagram protocols.
 *
 * Copyright (C) 2002 Trond Myklebust <trond.myklebust@fys.uio.no>
 */

#include <asm/param.h>

#include <linux/types.h>
#include <linux/unistd.h>
#include <linux/module.h>

#include <linux/sunrpc/clnt.h>

#define RPC_RTO_MAX (60*HZ)
#define RPC_RTO_INIT (HZ/5)
#define RPC_RTO_MIN (HZ/10)

/**
 * rpc_init_rtt - Initialize an RPC RTT estimator context
 * @rt: context to initialize
 * @timeo: initial timeout value, in jiffies
 *
 */
void rpc_init_rtt(struct rpc_rtt *rt, unsigned long timeo)
{
	unsigned long init = 0;
	unsigned int i;

	rt->timeo = timeo;

	if (timeo > RPC_RTO_INIT)
		init = (timeo - RPC_RTO_INIT) << 3;
	for (i = 0; i < 5; i++) {
		rt->srtt[i] = init;
		rt->sdrtt[i] = RPC_RTO_INIT;
		rt->ntimeouts[i] = 0;
	}
}
EXPORT_SYMBOL_GPL(rpc_init_rtt);

/**
 * rpc_update_rtt - Update an RPC RTT estimator context
 * @rt: context to update
 * @timer: timer array index (request type)
 * @m: recent actual RTT, in jiffies
 *
 * NB: When computing the smoothed RTT and standard deviation,
 *     be careful not to produce negative intermediate results.
 */
void rpc_update_rtt(struct rpc_rtt *rt, unsigned int timer, long m)
{
	long *srtt, *sdrtt;

	if (timer-- == 0)
		return;

	/* jiffies wrapped; ignore this one */
	if (m < 0)
		return;

	if (m == 0)
		m = 1L;

	srtt = (long *)&rt->srtt[timer];
	m -= *srtt >> 3;
	*srtt += m;

	if (m < 0)
		m = -m;

	sdrtt = (long *)&rt->sdrtt[timer];
	m -= *sdrtt >> 2;
	*sdrtt += m;

	/* Set lower bound on the variance */
	if (*sdrtt < RPC_RTO_MIN)
		*sdrtt = RPC_RTO_MIN;
}
EXPORT_SYMBOL_GPL(rpc_update_rtt);

/**
 * rpc_calc_rto - Provide an estimated timeout value
 * @rt: context to use for calculation
 * @timer: timer array index (request type)
 *
 * Estimate RTO for an NFS RPC sent via an unreliable datagram.  Use
 * the mean and mean deviation of RTT for the appropriate type of RPC
 * for frequently issued RPCs, and a fixed default for the others.
 *
 * The justification for doing "other" this way is that these RPCs
 * happen so infrequently that timer estimation would probably be
 * stale.  Also, since many of these RPCs are non-idempotent, a
 * conservative timeout is desired.
 *
 * getattr, lookup,
 * read, write, commit     - A+4D
 * other                   - timeo
 */
unsigned long rpc_calc_rto(struct rpc_rtt *rt, unsigned int timer)
{
	unsigned long res;

	if (timer-- == 0)
		return rt->timeo;

	res = ((rt->srtt[timer] + 7) >> 3) + rt->sdrtt[timer];
	if (res > RPC_RTO_MAX)
		res = RPC_RTO_MAX;

	return res;
}
EXPORT_SYMBOL_GPL(rpc_calc_rto);
e95ef8beb2047e8'>bcast.c</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/cgit.cgi/linux/net-next.git/log/net/tipc/bcast.c?id=fc6d39c39581f3c12c95f166ce95ef8beb2047e8&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
mmit/include/dt-bindings/reset/altr,rst-mgr.h?id=0263d4ebd94b36280608e296cba39b924b6e832b'>altr,rst-mgr.h</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='0263d4ebd94b36280608e296cba39b924b6e832b'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-24 12:38:43 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-24 12:38:43 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/dt-bindings/reset/altr,rst-mgr.h?id=0263d4ebd94b36280608e296cba39b924b6e832b'>0263d4ebd94b36280608e296cba39b924b6e832b</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/dt-bindings/reset/altr,rst-mgr.h?id=0263d4ebd94b36280608e296cba39b924b6e832b'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=0263d4ebd94b36280608e296cba39b924b6e832b'>6e21b4b3d8e8fb12cdfcfd185d46992487265a9b</a> /<a href='/cgit.cgi/linux/net-next.git/tree/include/dt-bindings/reset/altr,rst-mgr.h?id=0263d4ebd94b36280608e296cba39b924b6e832b'>include/dt-bindings/reset/altr,rst-mgr.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/dt-bindings/reset/altr,rst-mgr.h?id=19ca2c8fecb1592d623fe5e82d6796f8d446268d'>19ca2c8fecb1592d623fe5e82d6796f8d446268d</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/dt-bindings/reset/altr,rst-mgr.h?id=0263d4ebd94b36280608e296cba39b924b6e832b&amp;id2=19ca2c8fecb1592d623fe5e82d6796f8d446268d'>diff</a>)</td></tr><tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/dt-bindings/reset/altr,rst-mgr.h?id=7b9e1d89e1b6a3b99a8fdd949aa0f98dd5bf2f6b'>7b9e1d89e1b6a3b99a8fdd949aa0f98dd5bf2f6b</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/dt-bindings/reset/altr,rst-mgr.h?id=0263d4ebd94b36280608e296cba39b924b6e832b&amp;id2=7b9e1d89e1b6a3b99a8fdd949aa0f98dd5bf2f6b'>diff</a>)</td></tr></table>
<div class='commit-subject'>Merge tag 'platform-drivers-x86-v4.10-4' of git://git.infradead.org/linux-platform-drivers-x86</div><div class='commit-msg'>Pull x86 platform-driver fixes from Andy Shevchenko:
 "This is my first pull request since I become a co-maintainer of
  Platform Drivers x86 subsystem. It's a bit bigger than usual due to
  material collected for almost two weeks in a row.

  MAINTAINERS:
   - Add myself to X86 PLATFORM DRIVERS as a co-maintainer

  ideapad-laptop:
   - handle ACPI event 1

  intel_mid_powerbtn:
   - Set IRQ_ONESHOT

  surface3-wmi:
   - fix uninitialized symbol
   - Shut up unused-function warning

  mlx-platform:
   - free first dev on error"

* tag 'platform-drivers-x86-v4.10-4' of git://git.infradead.org/linux-platform-drivers-x86:
  MAINTAINERS: Add myself to X86 PLATFORM DRIVERS as a co-maintainer
  platform/x86: ideapad-laptop: handle ACPI event 1
  platform/x86: intel_mid_powerbtn: Set IRQ_ONESHOT
  platform/x86: surface3-wmi: fix uninitialized symbol
  platform/x86: surface3-wmi: Shut up unused-function warning
  platform/x86: mlx-platform: free first dev on error
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=0263d4ebd94b36280608e296cba39b924b6e832b'>Diffstat</a> (limited to 'include/dt-bindings/reset/altr,rst-mgr.h')</div><table summary='diffstat' class='diffstat'>