Messages in this thread | | | Subject | Re: [RFC] nvfs: a filesystem for persistent memory | From | Ritesh Harjani <> | Date | Tue, 22 Sep 2020 15:34:37 +0530 |
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On 9/15/20 6:30 PM, Matthew Wilcox wrote: > On Tue, Sep 15, 2020 at 08:34:41AM -0400, Mikulas Patocka wrote: >> - when the fsck.nvfs tool mmaps the device /dev/pmem0, the kernel uses >> buffer cache for the mapping. The buffer cache slows does fsck by a factor >> of 5 to 10. Could it be possible to change the kernel so that it maps DAX >> based block devices directly? > > Oh, because fs/block_dev.c has: > .mmap = generic_file_mmap, > > I don't see why we shouldn't have a blkdev_mmap modelled after > ext2_file_mmap() with the corresponding blkdev_dax_vm_ops. >
pls help with below 2 queries:-
1. Can't we use ->direct_IO here to avoid the mentioned performance problem? 2. Any other existing use case where having this blkdev_dax_vm_ops be useful?
-ritesh
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