I am testing the DDR4 NVDIMM on Debian 4.5.0-rc7. I enabled X86_PMEM_LEGACY, ACPI_NFIT and ACPI_NFIT_DEBUG with "make menuconfig". BIOS displays the following message
Just added 4G of Persistent (ADR) memory at =0x100000000
Just added 4G of Persistent (ADR) memory at =0x200000000
Just added 4G of Persistent (ADR) memory at =0x300000000
Just added 0x80000000 of Persistent (ADR) memory at =0x480000000
But, I do not see any persistent or protected memory with "dmesg | grep e820". There are no debug messages with any errors showing on screen or in the kernel log. How do I debug this?
Where does the data hand-off from BIOS/UEFI to kernel taking place? How do I trace the debug path for X86_PMEM_LEGACY and how does it work with/without ACPI_NFIT enabled?
Until now, dax has been disabled if media errors were found on
any device. This series attempts to address that.
The first three patches from Dan re-enable dax even when media
errors are present.
The fourth patch from Matthew removes the
zeroout path from dax entirely, making zeroout operations always
go through the driver (The motivation is that if a backing device
has media errors, and we create a sparse file on it, we don't
want the initial zeroing to happen via dax, we want to give the
block driver a chance to clear the errors).
The fifth patch changes the behaviour of dax_do_io by adding a
wrapper around it that is passed all the arguments also needed by
__blockdev_do_direct_IO. If (the new) __dax_do_io fails with -EIO
due to a bad block, we simply retry with the direct_IO path which
forces the IO to go through the block driver, and can attempt to
clear the error.
Dan Williams (3):
block, dax: pass blk_dax_ctl through to drivers
dax: fallback from pmd to pte on error
dax: enable dax in the presence of known media errors (badblocks)
Vishal Verma (2):
dax: use sb_issue_zerout instead of calling dax_clear_sectors
dax: handle media errors in dax_do_io
arch/powerpc/sysdev/axonram.c | 10 +++----
block/ioctl.c | 9 ------
drivers/block/brd.c | 9 +++---
drivers/nvdimm/pmem.c | 17 ++++++++---
drivers/s390/block/dcssblk.c | 12 ++++----
fs/block_dev.c | 7 +++--
fs/dax.c | 70 +++++++++++++++++++++----------------------
fs/ext2/inode.c | 12 ++++----
fs/ext4/indirect.c | 11 ++++---
fs/ext4/inode.c | 5 ++--
fs/xfs/xfs_aops.c | 7 +++--
fs/xfs/xfs_bmap_util.c | 9 ------
include/linux/blkdev.h | 3 +-
include/linux/dax.h | 7 +++--
14 files changed, 93 insertions(+), 95 deletions(-)