From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 C6BC76AD6; Fri, 26 Jan 2024 02:16:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706235402; cv=none; b=X4rIjYVji+hAvWiTpfLryEk1tiGqyTSPYu5lbkAGI3ASi1D/TDtiYYh+cDr/PmCOXYJ/WZnXWUGql/kmdTsaUL2o0cZvkxSr5teWwSCUJaB4Q6C9Pvr5c/+sQ3+zyshsbWFvyc9Kpd8r4KvnIV35LB9iwGUN9B2RoKXb2iA35mI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706235402; c=relaxed/simple; bh=KX1g7BnrjO9YTYHP+jTCG8fwDO7do9KS0BWOGiHsFyM=; h=Date:To:From:Subject:Message-Id; b=tScDBkzEwgojAgBwMyGCT1AEvExU6Ti7019lC9FM7Uqry/Ro+fieu8P+4RUBMxWHDJYMR8ooF5fwbaGci4VPRL/tYVQXbX7mF2bcHnut9oKFuVGUMoi5oFXU9kdZmx+8kQLrGFrdoAbEmnsHLdLtg0tBxi2v33z41/TWm/Nm4Eg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=ChaeGbYa; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="ChaeGbYa" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 31E92C433C7; Fri, 26 Jan 2024 02:16:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1706235402; bh=KX1g7BnrjO9YTYHP+jTCG8fwDO7do9KS0BWOGiHsFyM=; h=Date:To:From:Subject:From; b=ChaeGbYaw/Cf0FZvztKg8iF3coLH3EXPAop4zQQhOdkxVmonKWWW/SBtz1L50+QJG tfEcqI3hk8/IQ+JMIvRWC4k95PSsbTDgXZRhKHZAKp02/5wKNzqilhun5ybkt8bcut axljmpbgCUFHXpf/A/+Ae/VT1GA1G1su/F7/Gloc= Date: Thu, 25 Jan 2024 18:16:39 -0800 To: mm-commits@vger.kernel.org,ying.huang@intel.com,willy@infradead.org,osalvador@suse.de,nvdimm@lists.linux.dev,mhocko@suse.com,lizhijian@fujitsu.com,Jonathan.Cameron@huawei.com,gregkh@linuxfoundation.org,david@redhat.com,dave.jiang@intel.com,dave.hansen@linux.intel.com,dan.j.williams@intel.com,vishal.l.verma@intel.com,akpm@linux-foundation.org From: Andrew Morton Subject: + dax-add-a-sysfs-knob-to-control-memmap_on_memory-behavior.patch added to mm-unstable branch Message-Id: <20240126021642.31E92C433C7@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: dax: add a sysfs knob to control memmap_on_memory behavior has been added to the -mm mm-unstable branch. Its filename is dax-add-a-sysfs-knob-to-control-memmap_on_memory-behavior.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/dax-add-a-sysfs-knob-to-control-memmap_on_memory-behavior.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Vishal Verma Subject: dax: add a sysfs knob to control memmap_on_memory behavior Date: Wed, 24 Jan 2024 12:03:50 -0800 Add a sysfs knob for dax devices to control the memmap_on_memory setting if the dax device were to be hotplugged as system memory. The default memmap_on_memory setting for dax devices originating via pmem or hmem is set to 'false' - i.e. no memmap_on_memory semantics, to preserve legacy behavior. For dax devices via CXL, the default is on. The sysfs control allows the administrator to override the above defaults if needed. Link: https://lkml.kernel.org/r/20240124-vv-dax_abi-v7-5-20d16cb8d23d@intel.com Signed-off-by: Vishal Verma Tested-by: Li Zhijian Reviewed-by: Jonathan Cameron Reviewed-by: David Hildenbrand Reviewed-by: Huang, Ying Cc: Dan Williams Cc: Dave Jiang Cc: Dave Hansen Cc: Greg Kroah-Hartman Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Cc: Oscar Salvador Signed-off-by: Andrew Morton --- Documentation/ABI/testing/sysfs-bus-dax | 17 ++++++++ drivers/dax/bus.c | 43 ++++++++++++++++++++++ 2 files changed, 60 insertions(+) --- a/Documentation/ABI/testing/sysfs-bus-dax~dax-add-a-sysfs-knob-to-control-memmap_on_memory-behavior +++ a/Documentation/ABI/testing/sysfs-bus-dax @@ -134,3 +134,20 @@ KernelVersion: v5.1 Contact: nvdimm@lists.linux.dev Description: (RO) The id attribute indicates the region id of a dax region. + +What: /sys/bus/dax/devices/daxX.Y/memmap_on_memory +Date: January, 2024 +KernelVersion: v6.8 +Contact: nvdimm@lists.linux.dev +Description: + (RW) Control the memmap_on_memory setting if the dax device + were to be hotplugged as system memory. This determines whether + the 'altmap' for the hotplugged memory will be placed on the + device being hotplugged (memmap_on_memory=1) or if it will be + placed on regular memory (memmap_on_memory=0). This attribute + must be set before the device is handed over to the 'kmem' + driver (i.e. hotplugged into system-ram). Additionally, this + depends on CONFIG_MHP_MEMMAP_ON_MEMORY, and a globally enabled + memmap_on_memory parameter for memory_hotplug. This is + typically set on the kernel command line - + memory_hotplug.memmap_on_memory set to 'true' or 'force'." --- a/drivers/dax/bus.c~dax-add-a-sysfs-knob-to-control-memmap_on_memory-behavior +++ a/drivers/dax/bus.c @@ -1349,6 +1349,48 @@ static ssize_t numa_node_show(struct dev } static DEVICE_ATTR_RO(numa_node); +static ssize_t memmap_on_memory_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + + return sysfs_emit(buf, "%d\n", dev_dax->memmap_on_memory); +} + +static ssize_t memmap_on_memory_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + bool val; + int rc; + + rc = kstrtobool(buf, &val); + if (rc) + return rc; + + if (val == true && !mhp_supports_memmap_on_memory()) { + dev_dbg(dev, "memmap_on_memory is not available\n"); + return -EOPNOTSUPP; + } + + rc = down_write_killable(&dax_dev_rwsem); + if (rc) + return rc; + + if (dev_dax->memmap_on_memory != val && dev->driver && + to_dax_drv(dev->driver)->type == DAXDRV_KMEM_TYPE) { + up_write(&dax_dev_rwsem); + return -EBUSY; + } + + dev_dax->memmap_on_memory = val; + up_write(&dax_dev_rwsem); + + return len; +} +static DEVICE_ATTR_RW(memmap_on_memory); + static umode_t dev_dax_visible(struct kobject *kobj, struct attribute *a, int n) { struct device *dev = container_of(kobj, struct device, kobj); @@ -1375,6 +1417,7 @@ static struct attribute *dev_dax_attribu &dev_attr_align.attr, &dev_attr_resource.attr, &dev_attr_numa_node.attr, + &dev_attr_memmap_on_memory.attr, NULL, }; _ Patches currently in -mm which might be from vishal.l.verma@intel.com are dax-busc-replace-driver-core-lock-usage-by-a-local-rwsem.patch dax-busc-replace-several-sprintf-with-sysfs_emit.patch documentatiion-abi-add-abi-documentation-for-sys-bus-dax.patch mm-memory_hotplug-export-mhp_supports_memmap_on_memory.patch dax-add-a-sysfs-knob-to-control-memmap_on_memory-behavior.patch