On 7/10/25 1:03 AM, Christoph Hellwig wrote:
On Tue, Jul 08, 2025 at 09:11:41AM -0700, Bart Van Assche wrote:
* Slower booting of Linux devices that modify sysfs attributes
synchronously during boot.
So which attributes are regularly modified? Note that for read-ahead
it should be safe to drop the freeze as unlike the others it is not
used for splitting I/O to the limits accepted by the hardware. So
we could probably drop the freeze IFF the patch documents that it is
safe. But it still won't fix the root cause.
I can't answer the above question for all Linux distros. But I can
answer this question for Android. Here is what I found in the AOSP
platform code, which includes startup (.rc) scripts for all Android
vendors:
$ repo-grep -nHE 'write (/sys/block|/sys/class/block)' '**rc' | \
sed 's,.*/,,;s/ .*//' | sort | uniq -c | sort -rn | head -n5
46 read_ahead_kb # Implemented in block/blk-sysfs.c
27 scheduler # Implemented in block/blk-sysfs.c
20 slice_idle # BFQ I/O scheduler
17 comp_algorithm # zram kernel driver
4 discard_max_bytes # Implemented in block/blk-sysfs.c
Thanks,
Bart.
