All of lore.kernel.org
 help / color / mirror / Atom feed
From: Alex Chiang <achiang@hp.com>
To: Yinghai Lu <yinghai@kernel.org>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>,
	Ingo Molnar <mingo@elte.hu>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
	Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>,
	Bjorn Helgaas <bjorn.helgaas@hp.com>,
	linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org
Subject: Re: [PATCH 05/11] pci: update bridge res to get more big range in pci assign unssign
Date: Fri, 15 Jan 2010 21:38:47 -0700	[thread overview]
Message-ID: <20100116043847.GE22215@ldl.fc.hp.com> (raw)
In-Reply-To: <1263609721-3921-6-git-send-email-yinghai@kernel.org>

* Yinghai Lu <yinghai@kernel.org>:
> BIOS separate IO range between several IOHs, and on some slots,
> BIOS assign the resource to the bridge, but stop assigning
> resource to the device under that bridge, because the device
> need big resource.
> 
> 1. pci assign unassign and record the failed device resource.
> 2. clear the BIOS assigned resource of the parent bridge of fail device
> 3. go back and call pci assign unsigned
> 4. if it still fail, will go up more bridges. and clear and try again.

I agree with Jesse and Bjorn. I really hate introducing a new
command line param.

The goal here should be to do the right thing, all the time,
without requiring command line parameters.

I understand that you are avoiding a change to existing behavior
by defaulting to try=1.

What I don't understand is how you expect your change to benefit
any actual users. The usage model you propose is:

	- user encounters failure

	- user emails lkml/linux-pci and says "why doesn't my
	  device get resources?"

	- we tell user, "please reboot with try=N for increasing
	  values of N until it works"

Why shouldn't we be aggressive all the time?

If this patch series is going to be accepted, we should turn it
on all the time. Everyone will get the benefits.

If it breaks machines, depending on the bug reports, it will end
up either:

	a) we missed an implementation detail (easily fixed)

	or 

	b) the design/strategy is wrong, in which case we need to
	take a step back and think about a different approach to
	solve the problem you're trying to solve

For this patch, I don't mind the changes to
pci_assign_unassigned_resources(), but I really do not agree with
the configurability introduced in pci_setup().

thanks,
/ac

  reply	other threads:[~2010-01-16  4:38 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-16  2:41 [PATCH 00/11] pci: update pci bridge resources Yinghai Lu
2010-01-16  2:41 ` [PATCH 01/11] pci: add pci_bridge_release_unused_res and pci_bus_release_unused_bridge_res Yinghai Lu
2010-01-16  3:57   ` Alex Chiang
2010-01-16 10:10     ` Yinghai Lu
2010-01-16  2:41 ` [PATCH 02/11] pci: add failed_list to record failed one for pci_bus_assign_resources Yinghai Lu
2010-01-16  4:05   ` Alex Chiang
2010-01-16  2:41 ` [PATCH 03/11] pci: reject mmio range start from 0 on pci_bridge read Yinghai Lu
2010-01-16  4:20   ` Alex Chiang
2010-01-16  2:41 ` [PATCH 04/11] pci: don't shrink bridge resources Yinghai Lu
2010-01-16  2:41 ` [PATCH 05/11] pci: update bridge res to get more big range in pci assign unssign Yinghai Lu
2010-01-16  4:38   ` Alex Chiang [this message]
2010-01-16  2:41 ` [PATCH 06/11] pci: introduce pci_assign_unassigned_bridge_resources Yinghai Lu
2010-01-16  4:47   ` Alex Chiang
2010-01-16  2:41 ` [PATCH 07/11] pci: pciehp clean flow in pciehp_configure_device Yinghai Lu
2010-01-16  2:41 ` [PATCH 08/11] pci: pciehp second try to get big range for pcie devices Yinghai Lu
2010-01-16  4:52   ` Alex Chiang
2010-01-16  2:41 ` [PATCH 09/11] pci: pci_bridge_release_res Yinghai Lu
2010-01-16  4:57   ` Alex Chiang
2010-01-16  2:42 ` [PATCH 10/11] pciehp: add support for bridge resource reallocation Yinghai Lu
2010-01-16  4:59   ` Alex Chiang
2010-01-16  5:22     ` Yinghai Lu
2010-01-16  9:34     ` Yinghai Lu
2010-01-16 23:14       ` Bjorn Helgaas
2010-01-17 17:34         ` Jesse Barnes
2010-01-17 22:35           ` Yinghai Lu
2010-01-16  2:42 ` [PATCH 11/11] pci: set PCI_PREF_RANGE_TYPE_64 in pci_bridge_check_ranges Yinghai Lu
2010-01-16 11:07 [PATCH 00/11] pci: update pci bridge resources Yinghai Lu
2010-01-16 11:07 ` [PATCH 05/11] pci: update bridge res to get more big range in pci assign unssign Yinghai Lu
2010-01-19 21:48   ` Alex Chiang
2010-01-19 22:10     ` Yinghai Lu

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20100116043847.GE22215@ldl.fc.hp.com \
    --to=achiang@hp.com \
    --cc=bjorn.helgaas@hp.com \
    --cc=ink@jurassic.park.msu.ru \
    --cc=jbarnes@virtuousgeek.org \
    --cc=kaneshige.kenji@jp.fujitsu.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=mingo@elte.hu \
    --cc=torvalds@linux-foundation.org \
    --cc=yinghai@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.