[LU-15274] loose reverse readahead

• Status: Open
• Project: Lustre
• Type: Improvement
• Priority: Minor
• Reporter: Patrick Farrell
• Assignee: Patrick Farrell
• Resolution: Unresolved

Description

Some database queries end up going backwards through database files.  This is most often in a "loose backwards read" manner similar to the "loose forward reads" described in LU-15100.

Currently, reading backwards results in absolutely no readahead - every access is a miss.

This ticket is to try to implement a simple 'loose backwards read'.  (Backwards strided readahead is a separate challenge and is left for another time.)

Comments

[Gerrit Updater]

"Patrick Farrell <[e-mail]>" uploaded a new patch: https://review.whamcloud.com/45651
Subject: LU-15274 llite: Add forward/reverse to window
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: f8cf82ffcf113a71367d36db6f95dd066041cae2

[Gerrit Updater]

"Patrick Farrell <[e-mail]>" uploaded a new patch: https://review.whamcloud.com/45718
Subject: LU-15274 llite: Loose reverse readahead
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 2146656f16034b2a078da3d509ccfe93e05b2b92

[Gerrit Updater]

"Patrick Farrell <[e-mail]>" uploaded a new patch: https://review.whamcloud.com/45719
Subject: LU-15274 llite: Fix whole file read and fast_io
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 95375392ce53d76dec8ae48c8e1416bdd5925a2a

[Gerrit Updater]

"Patrick Farrell <[e-mail]>" uploaded a new patch: https://review.whamcloud.com/45720
Subject: LU-15274 llite: True whole file readahead
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 02badf5483317d461e46993a01d5c2ca98af74b6