From: Gioh Kim <gioh.kim@lge.com>
To: Colin Cross <ccross@android.com>, Joonsoo Kim <js1304@gmail.com>
Cc: "John Stultz" <john.stultz@linaro.org>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
lauraa@codeaurora.org, devel@driverdev.osuosl.org,
linux-kernel@vger.kernel.org,
"\"이건호/책임연구원/SW Platform(연)AOT팀(gunho.lee@lge.com)\""
<gunho.lee@lge.com>
Subject: Why does ion_cma_allocate need GFP_HIGHUSER | __GFP_ZERO flags?
Date: Thu, 13 Nov 2014 16:18:16 +0900 [thread overview]
Message-ID: <54645B38.10603@lge.com> (raw)
Hi,
I'm wondering why dma_alloc_coherent needs GFP_HIGHUSER | __GFP_ZERO flags in ion_cma_allocate().
I think dma_alloc_coherent can go to __dma_alloc if the system has CMA area.
If __GFP_WAIT flag is set, it allocates memory from atomic pool.
So I think calling dma_alloc_coherent with __GFP_WAIT is enough.
And can I get zero-filled-memory from CMA if I set __GFP_ZERO?
--
Thanks,
Gioh Kim
next reply other threads:[~2014-11-13 7:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-13 7:18 Gioh Kim [this message]
2014-11-14 1:24 ` Why does ion_cma_allocate need GFP_HIGHUSER | __GFP_ZERO flags? Laura Abbott
2014-11-14 1:38 ` Gioh Kim
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