From: Paolo Abeni <pabeni@redhat.com>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-fsdevel@vger.kernel.org,
Soheil Hassas Yeganeh <soheil@google.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Davidlohr Bueso <dave@stgolabs.net>,
Jason Baron <jbaron@akamai.com>, Roman Penyaev <rpenyaev@suse.de>,
netdev@vger.kernel.org, Carlos Maiolino <cmaiolino@redhat.com>
Subject: Re: [PATCH v2] epoll: use refcount to reduce ep_mutex contention
Date: Mon, 28 Nov 2022 18:50:09 +0100 [thread overview]
Message-ID: <3309d2b568c55642a2100ce51fcdbfc3d0bee072.camel@redhat.com> (raw)
In-Reply-To: <Y3/4FW4mqY3fWRfU@sol.localdomain>
Hello,
On Thu, 2022-11-24 at 15:02 -0800, Eric Biggers wrote:
[...]
> The behavior after this patch is that the resources aren't freed until the epoll
> file *and* all files that were added to it have been closed.
>
> Is that okay?
[...]
> But probably some users do things the other way around. I.e., they have a
> long-lived file descriptor that is repeatedly polled using different epoll
> instances that have a shorter lifetime.
>
> In that case, the number of 'struct eventpoll' and 'struct epitem' in kernel
> memory will keep growing until 'max_user_watches' is hit, at which point
> EPOLL_CTL_ADD will start failing with ENOSPC.
>
> Are you sure that is fine?
I have a new version of this patch which hopefully should address both
concerns. I'll share it soon.
Thanks!
Paolo
prev parent reply other threads:[~2022-11-28 18:06 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-24 17:57 [PATCH v2] epoll: use refcount to reduce ep_mutex contention Paolo Abeni
2022-11-24 21:57 ` Soheil Hassas Yeganeh
2022-11-24 23:02 ` Eric Biggers
2022-11-25 7:37 ` Paolo Abeni
2022-11-28 17:50 ` Paolo Abeni [this message]
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