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Mercier" , Christian =?utf-8?B?S8O2bmln?= , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org Subject: Re: Requirements to merge new heaps in the kernel Message-ID: <20241031-bouncy-cute-shrimp-cd2530@houat> References: <20241022-macaw-of-spectacular-joy-8dcefa@houat> <35deac48-4220-4889-833d-1b57b417e968@gmx.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha384; protocol="application/pgp-signature"; boundary="e7ghtd5lwxlkxgfh" Content-Disposition: inline In-Reply-To: <35deac48-4220-4889-833d-1b57b417e968@gmx.de> --e7ghtd5lwxlkxgfh Content-Type: text/plain; protected-headers=v1; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Subject: Re: Requirements to merge new heaps in the kernel MIME-Version: 1.0 On Wed, Oct 30, 2024 at 12:16:22PM +0100, metux wrote: > On 22.10.24 10:38, Maxime Ripard wrote: > > I'm still interested in merging a carve-out driver[1], since it seems t= o be > > in every vendor BSP and got asked again last week. > >=20 > > I remember from our discussion that for new heap types to be merged, we > > needed a kernel use-case. Looking back, I'm not entirely sure how one > > can provide that given that heaps are essentially facilities for > > user-space. >=20 > For those who didn't follow your work, could you please give a short > intro what's that all about ? >=20 > If I understand you correctly, you'd like the infrastructure of > kmalloc() et al for things / memory regions that aren't the usual heap, > right ? No, not really. The discussion is about dma-buf heaps. They allow to allocate buffers suitable for DMA from userspace. It might or might not =66rom the system memory, at the heap driver discretion. > What's the practical use case ? GPU memory ? Shared memory between > nodes in a multi-CPU / cluster machine ? >=20 > Is it related to NUMA ? And since it's about DMA, it doesn't have much to do with CPUs either. Maxime --e7ghtd5lwxlkxgfh Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iJUEABMJAB0WIQTkHFbLp4ejekA/qfgnX84Zoj2+dgUCZyO0HQAKCRAnX84Zoj2+ dsaIAYDSLs4vqC2W23GWmQw+nLt61ihhhwXON5VrB1bS7hVzaX7P2Gu1Vl0ygras mpk+w40Bf2OSx3W0bmcLT2VATGEiKE8QZJt+N49J3WfSZwJOPvQjXudAGBe5XxGj WjSuaDPXug== =PFmP -----END PGP SIGNATURE----- --e7ghtd5lwxlkxgfh--