Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

System-wide speculative prefetch limit. #14516

Merged
merged 1 commit into from
Mar 1, 2023
Merged

System-wide speculative prefetch limit. #14516

merged 1 commit into from
Mar 1, 2023
+25 −5

Commits on Feb 28, 2023

  1. System-wide speculative prefetch limit. 

    With some pathological access patterns it is possible to make ZFS
accumulate almost unlimited amount of speculative prefetch ZIOs.
Combined with linear ABD allocations in RAIDZ code, it appears to
be possible to exhaust system KVA, triggering kernel panic.

Address this by introducing a system-wide counter of active prefetch
requests and blocking prefetch distance doubling per stream hits if
the number of active requests is higher that ~6% of ARC size.

Signed-off-by:  Alexander Motin <[email protected]>
Sponsored by:	iXsystems, Inc.
    @amotin
    amotin committed Feb 28, 2023
    Configuration menu
    Copy the full SHA
    2599291 View commit details
    Browse the repository at this point in the history