From: Oliver Neukum <oneukum@suse.com>
To: Christoph Hellwig <hch@infradead.org>,
Jaewon Kim <jaewon31.kim@gmail.com>
Cc: linux-mm@kvack.org, gregkh@linuxfoundation.org,
Jaewon Kim <jaewon31.kim@samsung.com>,
m.szyprowski@samsung.com, ytk.lee@samsung.com,
linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org
Subject: Re: [RFC PATCH] usb: host: xhci: allow __GFP_FS in dma allocation
Date: Thu, 23 May 2019 14:32:09 +0200 [thread overview]
Message-ID: <1558614729.3994.5.camel@suse.com> (raw)
In-Reply-To: <20190520055657.GA31866@infradead.org>
On So, 2019-05-19 at 22:56 -0700, Christoph Hellwig wrote:
> Folks, you can't just pass arbitary GFP_ flags to dma allocation
> routines, beause very often they are not just wrappers around
> the page allocator.
>
> So no, you can't just fine grained control the flags, but the
> existing code is just as buggy.
>
> Please switch to use memalloc_noio_save() instead.
Thinking about this again, we have a problem. We introduced
memalloc_noio_save() in 3.10 . Hence the code should have been
correct in v4.14. Which means that either
6518202970c1 "(mm/cma: remove unsupported gfp_mask
parameter from cma_alloc()"
is buggy, or the original issue with a delay of 2 seconds
still exist.
Do we need to do something?
Regards
Oliver
next prev parent reply other threads:[~2019-05-23 12:45 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-17 16:02 [RFC PATCH] usb: host: xhci: allow __GFP_FS in dma allocation Jaewon Kim
2019-05-17 16:34 ` Matthew Wilcox
2019-05-18 1:53 ` Jaewon Kim
2019-05-20 5:56 ` Christoph Hellwig
2019-05-20 9:09 ` Oliver Neukum
2019-05-20 10:12 ` Christoph Hellwig
2019-05-20 14:16 ` Alan Stern
2019-05-20 14:23 ` Christoph Hellwig
2019-05-21 8:54 ` Oliver Neukum
2019-05-21 13:27 ` Christoph Hellwig
2019-05-21 13:11 ` Oliver Neukum
2019-05-21 14:00 ` Alan Stern
2019-05-22 6:31 ` Oliver Neukum
2019-05-22 14:56 ` Alan Stern
2019-05-22 20:47 ` Oliver Neukum
2019-05-23 14:01 ` Alan Stern
2019-05-28 12:34 ` Oliver Neukum
2019-05-28 14:25 ` Alan Stern
2019-05-23 12:32 ` Oliver Neukum [this message]
2019-05-23 16:35 ` Christoph Hellwig
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