Linux-RDMA Archive on lore.kernel.org
 help / color / Atom feed
From: Jason Gunthorpe <jgg@nvidia.com>
To: Eric Dumazet <edumazet@google.com>
Cc: Doug Ledford <dledford@redhat.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	<linux-rdma@vger.kernel.org>
Subject: Re: [PATCH net] RDMA/umem: add a schedule point in ib_umem_get()
Date: Fri, 31 Jul 2020 14:17:14 -0300
Message-ID: <20200731171714.GA513060@nvidia.com> (raw)
In-Reply-To: <20200730015755.1827498-1-edumazet@google.com>

On Wed, Jul 29, 2020 at 06:57:55PM -0700, Eric Dumazet wrote:
> Mapping as little as 64GB can take more than 10 seconds,
> triggering issues on kernels with CONFIG_PREEMPT_NONE=y.
> 
> ib_umem_get() already splits the work in 2MB units on x86_64,
> adding a cond_resched() in the long-lasting loop is enough
> to solve the issue.
> 
> Note that sg_alloc_table() can still use more than 100 ms,
> which is also problematic. This might be addressed later
> in ib_umem_add_sg_table(), adding new blocks in sgl
> on demand.

I have seen some patches in progress to do exactly this, the
motivation is to reduce the memory consumption if a lot of pages are
combined.

> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Doug Ledford <dledford@redhat.com>
> Cc: Jason Gunthorpe <jgg@ziepe.ca>
> Cc: linux-rdma@vger.kernel.org
> ---
>  drivers/infiniband/core/umem.c | 1 +
>  1 file changed, 1 insertion(+)

Why [PATCH net] ?

Anyhow, applied to rdma for-next

Thanks,
Jason

  reply index

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-30  1:57 Eric Dumazet
2020-07-31 17:17 ` Jason Gunthorpe [this message]
2020-07-31 17:21   ` Eric Dumazet

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=20200731171714.GA513060@nvidia.com \
    --to=jgg@nvidia.com \
    --cc=dledford@redhat.com \
    --cc=edumazet@google.com \
    --cc=eric.dumazet@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-rdma@vger.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

Linux-RDMA Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-rdma/0 linux-rdma/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-rdma linux-rdma/ https://lore.kernel.org/linux-rdma \
		linux-rdma@vger.kernel.org
	public-inbox-index linux-rdma

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-rdma


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git