Major Description
The DOM lock bit is taken opportunistically at open to improve possible read/write access but it uses PW lock mode and can be combined with other lock bits. The proposed improvements are:
1. when file is closed and there were no read/write, drop DOM bit and downgrade lock mode to less strict lock mode (CR/CW)
2. if there was write then write data on close (LU-11428) and also downgrade lock mode to PR
3. if DOM bit is dropped and there are other bits remains in lock - downgrade lock mode too
Attachments
Issue Links
- is related to
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LU-11428
Writeback on close for DoM
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- Open
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Activity
Mike Pershin (mpershin@whamcloud.com) uploaded a new patch: https://review.whamcloud.com/37105
Subject: LU-12325 ldlm: mode downgrade, wire changes
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 074008cdfc8e3e7efffc30e744896cda0da327d5
Mike Pershin (mpershin@whamcloud.com) uploaded a new patch: https://review.whamcloud.com/37088
Subject: LU-12325 ldlm: lock convert with mode downgrade
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: f872a4cbdaa4f7d52ef8fc9e0cbdcee041e50dad
yes, for write we need OPEN to return PW lock, so that is 'always' mode of dom_lock parameter.
patch https://review.whamcloud.com/35031 + dom_lock=trylock works for open-create, stat workload, but locks are still incompatible for "open-write + stat" workload, right?
patch https://review.whamcloud.com/35031 worked well and it can optimize performance for the following workload.
client1: open-create (zero byte file) client2: stat client1: stat
Here is test resutls.
dom_lock=always
[root@c082 ~]# /work/home/sihara/io-500-dev/bin/mdtest -C -F -d /es90/out -n 10000 -u [root@c082 ~]# lctl get_param ldlm.namespaces.*MDT0000*.lock_count ldlm.namespaces.es90-MDT0000-mdc-ffff92bf94e4d800.lock_count=10004 [root@c083 ~]# /work/home/sihara/io-500-dev/bin/mdtest -T -F -d /es90/out -n 10000 -u [root@c082 ~]# lctl get_param ldlm.namespaces.*MDT0000*.lock_count ldlm.namespaces.es90-MDT0000-mdc-ffff92bf94e4d800.lock_count=4 [root@c082 ~]# /work/home/sihara/io-500-dev/bin/mdtest -T -F -d /es90/out -n 10000 -u SUMMARY rate: (of 1 iterations) Operation Max Min Mean Std Dev --------- --- --- ---- ------- File creation : 0.000 0.000 0.000 0.000 File stat : 9145.261 9145.261 9145.261 0.000 File read : 0.000 0.000 0.000 0.000 File removal : 0.000 0.000 0.000 0.000 Tree creation : 0.000 0.000 0.000 0.000 Tree removal : 0.000 0.000 0.000 0.000
dom_lock=never
[root@c082 ~]# /work/home/sihara/io-500-dev/bin/mdtest -C -F -d /es90/out -n 10000 -u [root@c082 ~]# lctl get_param ldlm.namespaces.*MDT0000*.lock_count ldlm.namespaces.es90-MDT0000-mdc-ffff92bf94e4d800.lock_count=10004 [root@c083 ~]# /work/home/sihara/io-500-dev/bin/mdtest -T -F -d /es90/out -n 10000 -u [root@c082 ~]# lctl get_param ldlm.namespaces.*MDT0000*.lock_count ldlm.namespaces.es90-MDT0000-mdc-ffff92bf94e4d800.lock_count=10004 <--- c082 can keep locks, but it's still imcompatible for stat [root@c082 ~]# /work/home/sihara/io-500-dev/bin/mdtest -T -F -d /es90/out -n 10000 -u SUMMARY rate: (of 1 iterations) Operation Max Min Mean Std Dev --------- --- --- ---- ------- File creation : 0.000 0.000 0.000 0.000 File stat : 12923.465 12923.465 12923.465 0.000 File read : 0.000 0.000 0.000 0.000 File removal : 0.000 0.000 0.000 0.000 Tree creation : 0.000 0.000 0.000 0.000 Tree removal : 0.000 0.000 0.000 0.000
patch https://review.whamcloud.com/35031 + dom_lock=trylock
[root@c082 ~]# /work/home/sihara/io-500-dev/bin/mdtest -C -F -d /es90/out -n 10000 -u [root@c082 ~]# lctl get_param ldlm.namespaces.*MDT0000*.lock_count ldlm.namespaces.es90-MDT0000-mdc-ffff92bf94e4d800.lock_count=10004 [root@c083 ~]# /work/home/sihara/io-500-dev/bin/mdtest -T -F -d /es90/out -n 10000 -u [root@c082 ~]# lctl get_param ldlm.namespaces.*MDT0000*.lock_count ldlm.namespaces.es90-MDT0000-mdc-ffff92bf94e4d800.lock_count=10004 [root@c082 ~]# /work/home/sihara/io-500-dev/bin/mdtest -T -F -d /es90/out -n 10000 -u SUMMARY rate: (of 1 iterations) Operation Max Min Mean Std Dev --------- --- --- ---- ------- File creation : 0.000 0.000 0.000 0.000 File stat : 101680.001 101680.001 101680.001 0.000 <-- 10x faster File read : 0.000 0.000 0.000 0.000 File removal : 0.000 0.000 0.000 0.000 Tree creation : 0.000 0.000 0.000 0.000 Tree removal : 0.000 0.000 0.000 0.000
Mike Pershin (mpershin@whamcloud.com) uploaded a new patch: https://review.whamcloud.com/35031
Subject: LU-12325 dom: use LCK_PR with 'trylock' mode
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: fc6661cba7425757ec1a7f5ff5e2f1490fd2edcb
It might be related, but dom_lock=trylock behaviors chnaged in recent codes?
I'm testing on 2.15.0-RC3.
Dom lock mode "trylock" which is default.
Create new directory and configured dom for all < 1MB files.
Create 10000 files on client c01
locks were taken for 10000 files which is expected.
Another client ec02 issue "stats" to all 10000 files which client ec01 created above.
all locks for 10000 files on ec01 were canceled which is also expected.
But, why it requires 3 x locks against 10000 files for "stats"?
This was same scenarios of what I original tested in LU-12325, but different results and behaviors..
When I tested before, second client took same number of locks of target files for "stat". But, now it takes 3x..