All of lore.kernel.org
 help / color / mirror / Atom feed
From: Joerg Roedel <joro@8bytes.org>
To: Miles Chen <miles.chen@mediatek.com>
Cc: wsd_upstream@mediatek.com, robin.murphy@arm.com,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org,
	yf.wang@mediatek.com, iommu@lists.linux-foundation.org,
	will@kernel.org
Subject: Re: [PATCH] iommu/iova: Improve 32-bit free space estimate
Date: Fri, 4 Mar 2022 10:41:31 +0100	[thread overview]
Message-ID: <YiHey3lGHAMUp+oC@8bytes.org> (raw)
In-Reply-To: <20220303233646.13773-1-miles.chen@mediatek.com>

On Fri, Mar 04, 2022 at 07:36:46AM +0800, Miles Chen wrote:
> Hi Robin,
> 
> > For various reasons based on the allocator behaviour and typical
> > use-cases at the time, when the max32_alloc_size optimisation was
> > introduced it seemed reasonable to couple the reset of the tracked
> > size to the update of cached32_node upon freeing a relevant IOVA.
> > However, since subsequent optimisations focused on helping genuine
> > 32-bit devices make best use of even more limited address spaces, it
> > is now a lot more likely for cached32_node to be anywhere in a "full"
> > 32-bit address space, and as such more likely for space to become
> > available from IOVAs below that node being freed.
> > 
> > At this point, the short-cut in __cached_rbnode_delete_update() really
> > doesn't hold up any more, and we need to fix the logic to reliably
> > provide the expected behaviour. We still want cached32_node to only move
> > upwards, but we should reset the allocation size if *any* 32-bit space
> > has become available.
> > 
> > Reported-by: Yunfei Wang <yf.wang@mediatek.com>
> > Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> 
> Would you mind adding:
> 
> Cc: <stable@vger.kernel.org>

Applied without stable tag for now. If needed, please consider
re-sending it for stable when this patch is merged upstream.

Regards,

	Joerg
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <joro@8bytes.org>
To: Miles Chen <miles.chen@mediatek.com>
Cc: robin.murphy@arm.com, iommu@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org, will@kernel.org,
	wsd_upstream@mediatek.com, yf.wang@mediatek.com,
	stable@vger.kernel.org
Subject: Re: [PATCH] iommu/iova: Improve 32-bit free space estimate
Date: Fri, 4 Mar 2022 10:41:31 +0100	[thread overview]
Message-ID: <YiHey3lGHAMUp+oC@8bytes.org> (raw)
In-Reply-To: <20220303233646.13773-1-miles.chen@mediatek.com>

On Fri, Mar 04, 2022 at 07:36:46AM +0800, Miles Chen wrote:
> Hi Robin,
> 
> > For various reasons based on the allocator behaviour and typical
> > use-cases at the time, when the max32_alloc_size optimisation was
> > introduced it seemed reasonable to couple the reset of the tracked
> > size to the update of cached32_node upon freeing a relevant IOVA.
> > However, since subsequent optimisations focused on helping genuine
> > 32-bit devices make best use of even more limited address spaces, it
> > is now a lot more likely for cached32_node to be anywhere in a "full"
> > 32-bit address space, and as such more likely for space to become
> > available from IOVAs below that node being freed.
> > 
> > At this point, the short-cut in __cached_rbnode_delete_update() really
> > doesn't hold up any more, and we need to fix the logic to reliably
> > provide the expected behaviour. We still want cached32_node to only move
> > upwards, but we should reset the allocation size if *any* 32-bit space
> > has become available.
> > 
> > Reported-by: Yunfei Wang <yf.wang@mediatek.com>
> > Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> 
> Would you mind adding:
> 
> Cc: <stable@vger.kernel.org>

Applied without stable tag for now. If needed, please consider
re-sending it for stable when this patch is merged upstream.

Regards,

	Joerg

  reply	other threads:[~2022-03-04  9:41 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-03 14:40 [PATCH] iommu/iova: Improve 32-bit free space estimate Robin Murphy
2022-03-03 14:40 ` Robin Murphy
2022-03-03 23:08 ` Miles Chen via iommu
2022-03-03 23:08   ` Miles Chen
2022-03-03 23:36 ` Miles Chen via iommu
2022-03-03 23:36   ` Miles Chen
2022-03-04  9:41   ` Joerg Roedel [this message]
2022-03-04  9:41     ` Joerg Roedel
2022-03-04 11:32     ` Robin Murphy
2022-03-04 11:32       ` Robin Murphy
2022-03-05  0:03       ` Miles Chen via iommu
2022-03-05  0:03         ` Miles Chen

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=YiHey3lGHAMUp+oC@8bytes.org \
    --to=joro@8bytes.org \
    --cc=iommu@lists.linux-foundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=miles.chen@mediatek.com \
    --cc=robin.murphy@arm.com \
    --cc=stable@vger.kernel.org \
    --cc=will@kernel.org \
    --cc=wsd_upstream@mediatek.com \
    --cc=yf.wang@mediatek.com \
    /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.