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Mon, 1 Dec 2025 09:34:34 +0100 (CET) Date: Mon, 1 Dec 2025 09:34:32 +0100 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 , Jonathan Corbet , Christopher Healy , Matthew Wilcox , Bagas Sanjaya , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, kernel@collabora.com Subject: Re: [PATCH v10 04/10] drm/gem: Add huge tmpfs mountpoint helpers Message-ID: <20251201093432.5cd45ae0@fedora> In-Reply-To: <20251128185252.3092-5-loic.molinari@collabora.com> References: <20251128185252.3092-1-loic.molinari@collabora.com> <20251128185252.3092-5-loic.molinari@collabora.com> Organization: Collabora X-Mailer: Claws Mail 4.3.1 (GTK 3.24.51; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Queue-Id: 47FB74000B X-Rspamd-Server: rspam11 X-Stat-Signature: zrx5aw5zhcij5cfisstksfk5o7acn18y X-HE-Tag: 1764578077-262499 X-HE-Meta: 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 zDcaNkmM Wk2Uf5TFp/KTiVgEyFygy257VXoYhDkDutYfwtDesef0k2CODjUx0/L+UtuIouCi1bWdQVZqwo7rChhYxZIaSSZoqZksxaqBFePid375OmopE4jZ5hOgQvICnPnevN4oBAduxow1CnVQkfil+/oKF/gp3+2jrXtRsjWkjhdtBIYTK2qAyI9hUCHUpQnDxmQaVS0Z9+j/f8KeX2jdPJ6ZqT0EyRLRXnYXP+9P9m/zlcwp7FpGD48AZokQzxdp4lZK/pReUpax3oKTyWpI8wAAfpbAG4J/yvBAt3gqf96tjsLNZ9tQD8p7bNpwzrMMwTMe+bGZmrTqCKOL01SVdbJetjB0N0W/wcMpgYtcP4GYtAXL0dMuaMgHjkOBEjw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, 28 Nov 2025 19:52:46 +0100 Lo=C3=AFc Molinari wrote: > Add the drm_gem_huge_mnt_create() and drm_gem_get_huge_mnt() helpers > to avoid code duplication in the i915, V3D, Panfrost and Panthor > drivers. The former creates and mounts a dedicated huge tmpfs > mountpoint, for the lifetime of a DRM device, used at GEM object > initialization. The latter retrieves the dedicated huge tmpfs > mountpoint used by a DRM device. >=20 > The next commits will port drivers to these helpers. >=20 > v3: > - store huge tmpfs mountpoint in drm_device >=20 > v4: > - return 0 in builds with CONFIG_TRANSPARENT_HUGEPAGE=3Dn > - return 0 when huge_mnt already exists > - use new vfs_parse_fs_string() helper >=20 > v5: > - remove warning on !dev->huge_mnt and reset to NULL on free > - inline drm_gem_huge_mnt_create() to remove func from text and avoid > calls in builds with CONFIG_TRANSPARENT_HUGEPAGE=3Dn > - compile out drm_device's huge_mnt field in builds with > CONFIG_TRANSPARENT_HUGEPAGE=3Dn > - add drm_gem_has_huge_mnt() helper >=20 > v6: > - move huge_mnt doc into ifdef'd section > - either inline or export drm_gem_huge_mnt_create() >=20 > v7: > - include in drm_gem.h >=20 > v9: > - replace drm_gem_has_huge_mnt() by drm_gem_get_huge_mnt() >=20 > Signed-off-by: Lo=C3=AFc Molinari Reviewed-by: Boris Brezillon > --- > drivers/gpu/drm/drm_gem.c | 57 +++++++++++++++++++++++++++++++++++++++ > include/drm/drm_device.h | 15 +++++++++++ > include/drm/drm_gem.h | 33 +++++++++++++++++++++++ > 3 files changed, 105 insertions(+) >=20 > diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c > index 41d344c270a7..94e5e04865ba 100644 > --- a/drivers/gpu/drm/drm_gem.c > +++ b/drivers/gpu/drm/drm_gem.c > @@ -29,6 +29,9 @@ > #include > #include > #include > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > +#include > +#endif > #include > #include > #include > @@ -82,6 +85,60 @@ > * up at a later date, and as our interface with shmfs for memory alloca= tion. > */ > =20 > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > +static void drm_gem_huge_mnt_free(struct drm_device *dev, void *data) > +{ > + kern_unmount(dev->huge_mnt); > +} > + > +/** > + * drm_gem_huge_mnt_create - Create, mount and use a huge tmpfs mountpoi= nt > + * @dev: DRM device a huge tmpfs mountpoint should be used with > + * @value: huge tmpfs mount option value > + * > + * This function creates and mounts a dedicated huge tmpfs mountpoint fo= r the > + * lifetime of the DRM device @dev which is used at GEM object initializ= ation > + * with drm_gem_object_init(). > + * > + * The most common option value @value is "within_size" which only alloc= ates > + * huge pages if the page will be fully within the GEM object size. "alw= ays", > + * "advise" and "never" are supported too but the latter would just crea= te a > + * mountpoint similar to the default one (`shm_mnt`). See shmemfs and > + * Transparent Hugepage for more information. > + * > + * Returns: > + * 0 on success or a negative error code on failure. > + */ > +int drm_gem_huge_mnt_create(struct drm_device *dev, const char *value) > +{ > + struct file_system_type *type; > + struct fs_context *fc; > + int ret; > + > + if (unlikely(drm_gem_get_huge_mnt(dev))) > + return 0; > + > + type =3D get_fs_type("tmpfs"); > + if (unlikely(!type)) > + return -EOPNOTSUPP; > + fc =3D fs_context_for_mount(type, SB_KERNMOUNT); > + if (IS_ERR(fc)) > + return PTR_ERR(fc); > + ret =3D vfs_parse_fs_string(fc, "source", "tmpfs"); > + if (unlikely(ret)) > + return -ENOPARAM; > + ret =3D vfs_parse_fs_string(fc, "huge", value); > + if (unlikely(ret)) > + return -ENOPARAM; > + > + dev->huge_mnt =3D fc_mount_longterm(fc); > + put_fs_context(fc); > + > + return drmm_add_action_or_reset(dev, drm_gem_huge_mnt_free, NULL); > +} > +EXPORT_SYMBOL_GPL(drm_gem_huge_mnt_create); > +#endif > + > static void > drm_gem_init_release(struct drm_device *dev, void *ptr) > { > diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h > index 5af49c5c3778..7dc560ad14fc 100644 > --- a/include/drm/drm_device.h > +++ b/include/drm/drm_device.h > @@ -3,6 +3,9 @@ > =20 > #include > #include > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > +#include > +#endif > #include > #include > #include > @@ -168,6 +171,18 @@ struct drm_device { > */ > struct drm_master *master; > =20 > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > + /** > + * @huge_mnt: > + * > + * Huge tmpfs mountpoint used at GEM object initialization > + * drm_gem_object_init(). Drivers can call drm_gem_huge_mnt_create() to > + * create a huge tmfps mountpoint. The default tmpfs mountpoint > + * (`shm_mnt`) is used if NULL. > + */ > + struct vfsmount *huge_mnt; > +#endif > + > /** > * @driver_features: per-device driver features > * > diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h > index 7c8bd67d087c..4e9ab5d294ac 100644 > --- a/include/drm/drm_gem.h > +++ b/include/drm/drm_gem.h > @@ -40,6 +40,9 @@ > #include > #include > =20 > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > +#include > +#endif > #include > =20 > struct iosys_map; > @@ -492,6 +495,36 @@ struct drm_gem_object { > DRM_GEM_FOPS,\ > } > =20 > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > +int drm_gem_huge_mnt_create(struct drm_device *dev, const char *value); > +#else > +static inline int drm_gem_huge_mnt_create(struct drm_device *dev, > + const char *value) > +{ > + return 0; > +} > +#endif > + > +/** > + * drm_gem_get_huge_mnt - Get the huge tmpfs mountpoint used by a DRM de= vice > + * @dev: DRM device > + > + * This function gets the huge tmpfs mountpoint used by DRM device @dev.= A huge > + * tmpfs mountpoint is used after a successful call to drm_gem_huge_mnt_= create() > + * on builds with Transparent Hugepage enabled. > + > + * Returns: > + * The huge tmpfs mountpoint in use, NULL otherwise. > + */ > +static inline struct vfsmount *drm_gem_get_huge_mnt(struct drm_device *d= ev) > +{ > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > + return dev->huge_mnt; > +#else > + return NULL; > +#endif > +} > + > void drm_gem_object_release(struct drm_gem_object *obj); > void drm_gem_object_free(struct kref *kref); > int drm_gem_object_init(struct drm_device *dev,