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From:   "Tian, Kevin" <kevin.tian@intel.com>
To:     "Chatre, Reinette" <reinette.chatre@intel.com>,
        "jgg@nvidia.com" <jgg@nvidia.com>,
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Subject: RE: [PATCH V4 08/11] vfio/pci: Use bitfield for struct
 vfio_pci_core_device flags
Thread-Topic: [PATCH V4 08/11] vfio/pci: Use bitfield for struct
 vfio_pci_core_device flags
Thread-Index: AQHZeS7PmQqzYDHQq0qJjERkHaB3kq9ARu/w
Date:   Fri, 28 Apr 2023 06:43:00 +0000
Message-ID: <BN9PR11MB52768311F5FA320283B06C358C6B9@BN9PR11MB5276.namprd11.prod.outlook.com>
References: <cover.1682615447.git.reinette.chatre@intel.com>
 <42397f8cd0419694797c6c5cf65ed715117fc760.1682615447.git.reinette.chatre@intel.com>
In-Reply-To: <42397f8cd0419694797c6c5cf65ed715117fc760.1682615447.git.reinette.chatre@intel.com>
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> From: Chatre, Reinette <reinette.chatre@intel.com>
> Sent: Friday, April 28, 2023 1:36 AM
>=20
> struct vfio_pci_core_device contains eleven boolean flags.
> Boolean flags clearly indicate their usage but space usage
> starts to be a concern when there are many.
>=20
> An upcoming change adds another boolean flag to
> struct vfio_pci_core_device, thereby increasing the concern
> that the boolean flags are consuming unnecessary space.
>=20
> Transition the boolean flags to use bitfields. On a system that
> uses one byte per boolean this reduces the space consumed
> by existing flags from 11 bytes to 2 bytes with room for
> a few more flags without increasing the structure's size.
>=20
> Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>

Reviewed-by: Kevin Tian <kevin.tian@intel.com>