From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 64F493208 for ; Mon, 6 Oct 2025 06:52:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.251.105.195 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759733577; cv=none; b=eXogMTU+A+/KEv+54IN84h6Tk6FLfWSSH/qXZw2Z0ztJ2vkdNjNSM+Wi9pPEXOa9KBA8Ppbn6Ec8uHRaRynP9BhdSE0tQ91e/jZH5rPB4KXx8Qk2Za/0Tqd2/JxOdXbbktPSzENIurXMd8+ERO9ga2HS5iPepoLYq7cM0EPEJ+8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759733577; c=relaxed/simple; bh=dz/7ybhFy53bNalb8jRF6/95hGJfso+9p3SQZuWaD+w=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=um1625gmTsRzq/81WNCC/vptRx24l4YvdCKlMsQsTL+zGsKe0i+JPGaefrNalzccdwfystHk1I75TTbWjP9BYo2xRtL52VKujdxytEf/4JRSsUdhW5eMTUxZ6bUR+DfpsVOgD0X2OBwGwgRXtB2g2Ba+CmawkiKhwgVwhPKKfZc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b=eIwlSBHH; arc=none smtp.client-ip=148.251.105.195 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="eIwlSBHH" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1759733572; bh=dz/7ybhFy53bNalb8jRF6/95hGJfso+9p3SQZuWaD+w=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=eIwlSBHHSU3fGpgntkmPgbspid1vf+fh1JA91yxAY6BJMprianRhs2g6YgCGjCuT+ ojdXWJPfdA926eGkHDJ864aW57Ntr8XblLboCkbpRwnnkcPzUo2208o+A0ik1zQWx3 E/3y4Pg075Zq/9MU7ziDIdiAnYTXh0GNZ4u+/KxBvkLSh2Sb3Z8BcRTyKwqQUq8s76 8li7JiqVY7anifjlHOR0rfFyVRjgMtemgO1XGquYJCcv64T530YToTfq5UQSzMBmJD kiLUoKNzQPFCM7b+QiiAe/ljf3G9b3/GtyyIGfAEGXlbbL466HvAh8q/gqVtDlpO9U cqd76BOVb58EQ== Received: from fedora (unknown [IPv6:2a01:e0a:2c:6930:d919:a6e:5ea1:8a9f]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bbrezillon) by bali.collaboradmins.com (Postfix) with ESMTPSA id 543B617E0AC3; Mon, 6 Oct 2025 08:52:51 +0200 (CEST) Date: Mon, 6 Oct 2025 08:52:47 +0200 From: Boris Brezillon To: =?UTF-8?B?TG/Dr2M=?= Molinari Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , Rob Herring , Steven Price , Liviu Dudau , Melissa Wen , =?UTF-8?B?TWHDrXJh?= Canal , Hugh Dickins , Baolin Wang , Andrew Morton , Al Viro , =?UTF-8?B?TWlrb8WCYWo=?= Wasiak , Christian Brauner , Nitin Gote , Andi Shyti , Christopher Healy , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-mm@kvack.org, kernel@collabora.com, kernel test robot Subject: Re: [PATCH v3 01/10] drm/shmem-helper: Add huge page fault handler Message-ID: <20251006085247.52f29f59@fedora> In-Reply-To: <20251004093054.21388-2-loic.molinari@collabora.com> References: <20251004093054.21388-1-loic.molinari@collabora.com> <20251004093054.21388-2-loic.molinari@collabora.com> Organization: Collabora X-Mailer: Claws Mail 4.3.1 (GTK 3.24.49; x86_64-redhat-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Sat, 4 Oct 2025 11:30:44 +0200 Lo=C3=AFc Molinari wrote: > This gives the mm subsystem the ability to propose the insertion of > PUD or PMD-sized mappings for the faulting addresses. >=20 > On builds with CONFIG_TRANSPARENT_HUGEPAGE enabled, if the mmap() user > address is aligned to a huge page size, if the GEM object is backed by > shmem buffers on mount points setting the 'huge=3D' option and if the > shmem backing store manages to allocate a huge folio, the CPU mapping > will then benefit from significantly increased memcpy() performance. > When these conditions are met on a system with 2 MiB huge pages, an > aligned copy of 2 MiB would raise a single page fault instead of 4096. >=20 > v2: > - set ret to VM_FAULT_FALLBACK in default switch statement > - ifdef out paddr declaration >=20 > Signed-off-by: Lo=C3=AFc Molinari > Reviewed-by: Boris Brezillon > Reported-by: kernel test robot > Closes: https://lore.kernel.org/oe-kbuild-all/202509241315.8jjCyL7U-lkp@i= ntel.com/ > Closes: https://lore.kernel.org/oe-kbuild-all/202509241654.qJk1H5kr-lkp@i= ntel.com/ > Closes: https://lore.kernel.org/oe-kbuild-all/202509241920.PtSEkfd4-lkp@i= ntel.com/ I'm not sure those Closes/Reported-by tags are needed when you fix bugs introduced in a previous revisions of the patchset. > --- > drivers/gpu/drm/drm_gem_shmem_helper.c | 56 ++++++++++++++++++++++++-- > 1 file changed, 52 insertions(+), 4 deletions(-) >=20 > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm= _gem_shmem_helper.c > index 50594cf8e17c..22c4b09e10a3 100644 > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > @@ -573,7 +573,8 @@ int drm_gem_shmem_dumb_create(struct drm_file *file, = struct drm_device *dev, > } > EXPORT_SYMBOL_GPL(drm_gem_shmem_dumb_create); > =20 > -static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) > +static vm_fault_t drm_gem_shmem_huge_fault(struct vm_fault *vmf, > + unsigned int order) > { > struct vm_area_struct *vma =3D vmf->vma; > struct drm_gem_object *obj =3D vma->vm_private_data; > @@ -582,6 +583,10 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_faul= t *vmf) > vm_fault_t ret; > struct page *page; > pgoff_t page_offset; > + unsigned long pfn; > +#if defined(CONFIG_ARCH_SUPPORTS_PMD_PFNMAP) || defined(CONFIG_ARCH_SUPP= ORTS_PUD_PFNMAP) > + unsigned long paddr; > +#endif > =20 > /* We don't use vmf->pgoff since that has the fake offset */ > page_offset =3D (vmf->address - vma->vm_start) >> PAGE_SHIFT; > @@ -592,17 +597,57 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fau= lt *vmf) > drm_WARN_ON_ONCE(obj->dev, !shmem->pages) || > shmem->madv < 0) { > ret =3D VM_FAULT_SIGBUS; > - } else { > - page =3D shmem->pages[page_offset]; > + goto out; > + } > =20 > - ret =3D vmf_insert_pfn(vma, vmf->address, page_to_pfn(page)); > + page =3D shmem->pages[page_offset]; > + pfn =3D page_to_pfn(page); > + > + switch (order) { > + case 0: > + ret =3D vmf_insert_pfn(vma, vmf->address, pfn); > + break; > + > +#ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP > + case PMD_ORDER: > + paddr =3D pfn << PAGE_SHIFT; > + if (((vmf->address & ~PMD_MASK) =3D=3D (paddr & ~PMD_MASK)) && > + (folio_order(page_folio(page)) =3D=3D PMD_ORDER)) > + ret =3D vmf_insert_pfn_pmd( > + vmf, pfn & (PMD_MASK >> PAGE_SHIFT), false); > + else > + ret =3D VM_FAULT_FALLBACK; > + break; > +#endif > + > +#ifdef CONFIG_ARCH_SUPPORTS_PUD_PFNMAP > + case PUD_ORDER: > + paddr =3D pfn << PAGE_SHIFT; > + if (((vmf->address & ~PUD_MASK) =3D=3D (paddr & ~PUD_MASK)) && > + (folio_order(page_folio(page)) =3D=3D PUD_ORDER)) > + ret =3D vmf_insert_pfn_pud( > + vmf, pfn & (PUD_MASK >> PAGE_SHIFT), false); > + else > + ret =3D VM_FAULT_FALLBACK; > + break; > +#endif > + > + default: > + ret =3D VM_FAULT_FALLBACK; > + break; > } > =20 > + out: > dma_resv_unlock(shmem->base.resv); > =20 > return ret; > } > =20 > +static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) > +{ > + return drm_gem_shmem_huge_fault(vmf, 0); > +} > + > static void drm_gem_shmem_vm_open(struct vm_area_struct *vma) > { > struct drm_gem_object *obj =3D vma->vm_private_data; > @@ -639,6 +684,9 @@ static void drm_gem_shmem_vm_close(struct vm_area_str= uct *vma) > =20 > const struct vm_operations_struct drm_gem_shmem_vm_ops =3D { > .fault =3D drm_gem_shmem_fault, > +#if defined(CONFIG_ARCH_SUPPORTS_PMD_PFNMAP) || defined(CONFIG_ARCH_SUPP= ORTS_PUD_PFNMAP) > + .huge_fault =3D drm_gem_shmem_huge_fault, > +#endif > .open =3D drm_gem_shmem_vm_open, > .close =3D drm_gem_shmem_vm_close, > };