From: John Stultz <jstultz@google.com>
To: jaewon31.kim@samsung.com
Cc: "T.J. Mercier" <tjmercier@google.com>,
"sumit.semwal@linaro.org" <sumit.semwal@linaro.org>,
"daniel.vetter@ffwll.ch" <daniel.vetter@ffwll.ch>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"hannes@cmpxchg.org" <hannes@cmpxchg.org>,
"mhocko@kernel.org" <mhocko@kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"jaewon31.kim@gmail.com" <jaewon31.kim@gmail.com>
Subject: Re: (2) [PATCH] dma-buf: system_heap: avoid reclaim for order 4
Date: Tue, 7 Feb 2023 08:56:07 -0800 [thread overview]
Message-ID: <CANDhNCpM+R0sPuGoeBW0=he+6YMKTn2YLm4AZZ2+C=5YRLZBLg@mail.gmail.com> (raw)
In-Reply-To: <20230207073335epcms1p15df191db83bec0cb791e6f79dcecb31f@epcms1p1>
On Mon, Feb 6, 2023 at 11:33 PM Jaewon Kim <jaewon31.kim@samsung.com> wrote:
> >I don't mean to discourage you, especially after all the effort here.
> >
> >Do you think evaluating the before and after impact to buffer usage
> >
> >(not just allocation) would be doable in the near term?
> >
>
> Hello sorry but I don't have expertise on iommu. Actually I'm also wondering
> all IOMMU can use order 4 free pages, if they are allocated. I am not sure
> but I remember I heard order 9 (2MB) could be used, but I don't know about order 8 4.
>
> I guess IOMMU mmap also be same patern like we expect. I mean if order 4 is
> prepared it could be faster like 1 to 4 times. But it, I think, should NOT be
> that much slow even though the entire free memory is prepared as order 0 pages.
>
> >
> >
> >If you don't think so, given the benefit to allocation under pressure
> >
> >is large (and I don't mean to give you hurdles to jump), I'm willing
> >
> >to ack your change to get it merged, but if we later see performance
> >
> >trouble, I'll be quick to advocate for reverting it. Is that ok?
> >
>
> Yes sure. I also want to know if it is.
Ok. Please resend your latest patch and I'll go ahead and ack it and
we'll watch.
Thanks again for your efforts here!
-john
prev parent reply other threads:[~2023-02-07 16:56 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20230117082521epcas1p22a709521a9e6d2346d06ac220786560d@epcas1p2.samsung.com>
2023-01-17 8:25 ` [PATCH] dma-buf: system_heap: avoid reclaim for order 4 Jaewon Kim
[not found] ` <CGME20230117082521epcas1p22a709521a9e6d2346d06ac220786560d@epcms1p6>
2023-01-17 8:31 ` Jaewon Kim
2023-01-18 6:54 ` John Stultz
2023-01-18 19:55 ` T.J. Mercier
[not found] ` <CGME20230117082521epcas1p22a709521a9e6d2346d06ac220786560d@epcms1p2>
2023-01-25 9:56 ` Jaewon Kim
2023-01-25 10:19 ` Jaewon Kim
2023-01-25 20:32 ` John Stultz
[not found] ` <CGME20230117082521epcas1p22a709521a9e6d2346d06ac220786560d@epcms1p3>
2023-01-26 4:42 ` 김재원
2023-01-26 5:04 ` (2) " John Stultz
[not found] ` <CGME20230117082521epcas1p22a709521a9e6d2346d06ac220786560d@epcms1p8>
2023-01-18 7:30 ` Jaewon Kim
2023-02-04 15:02 ` Jaewon Kim
2023-02-07 4:37 ` (2) " John Stultz
[not found] ` <CGME20230117082521epcas1p22a709521a9e6d2346d06ac220786560d@epcms1p1>
2023-02-07 7:33 ` Jaewon Kim
2023-02-07 16:56 ` John Stultz [this message]
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