From: Hridya Valsaraju <hridya@google.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Sumit Semwal" <sumit.semwal@linaro.org>,
"Christian König" <christian.koenig@amd.com>,
"Daniel Vetter" <daniel.vetter@ffwll.ch>,
linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org,
john.stultz@linaro.org, surenb@google.com,
kaleshsingh@google.com, tjmercier@google.com,
keescook@google.com
Subject: Re: [PATCH] dma-buf: Move sysfs work out of DMA-BUF export/release path
Date: Wed, 5 Jan 2022 10:38:02 -0800 [thread overview]
Message-ID: <CA+wgaPPSO1f=c+jYWqisNy_e8hxuxcr0VtpJcWe+FnKGyC2ZKg@mail.gmail.com> (raw)
In-Reply-To: <YdW1hPRvKYjfORvp@kroah.com>
On Wed, Jan 5, 2022 at 7:13 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Tue, Jan 04, 2022 at 03:51:48PM -0800, Hridya Valsaraju wrote:
> > Recently, we noticed an issue where a process went into direct reclaim
> > while holding the kernfs rw semaphore for sysfs in write(exclusive)
> > mode. This caused processes who were doing DMA-BUF exports and releases
> > to go into uninterruptible sleep since they needed to acquire the same
> > semaphore for the DMA-BUF sysfs entry creation/deletion. In order to avoid
> > blocking DMA-BUF export/release for an indeterminate amount of time
> > while another process is holding the sysfs rw semaphore in exclusive
> > mode, this patch moves the per-buffer sysfs file creation/deleteion to
> > a kthread.
> >
> > Fixes: bdb8d06dfefd ("dmabuf: Add the capability to expose DMA-BUF stats in sysfs")
> > Signed-off-by: Hridya Valsaraju <hridya@google.com>
> > ---
> > drivers/dma-buf/dma-buf-sysfs-stats.c | 343 ++++++++++++++++++++++++--
> > include/linux/dma-buf.h | 46 ++++
> > 2 files changed, 366 insertions(+), 23 deletions(-)
>
> Crazy, but if this works in your testing, it looks ok to me. Nice work.
>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Thank you for the review Greg :)
next prev parent reply other threads:[~2022-01-05 18:38 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-04 23:51 [PATCH] dma-buf: Move sysfs work out of DMA-BUF export/release path Hridya Valsaraju
2022-01-05 15:13 ` Greg Kroah-Hartman
2022-01-05 18:38 ` Hridya Valsaraju [this message]
2022-01-06 8:59 ` Christian König
2022-01-06 19:04 ` Hridya Valsaraju
2022-01-07 10:22 ` Christian König
2022-01-07 18:17 ` Hridya Valsaraju
2022-01-07 21:25 ` Hridya Valsaraju
2022-01-10 7:28 ` Christian König
2022-01-11 6:01 ` Hridya Valsaraju
2022-01-11 8:35 ` Daniel Vetter
2022-01-11 10:58 ` Christian König
2022-01-11 11:16 ` Greg Kroah-Hartman
2022-01-11 11:43 ` Christian König
2022-01-12 1:11 ` Hridya Valsaraju
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