On Thu, 23 May 2013, Yan, Zheng wrote:
> From: "Yan, Zheng" <zheng.z.yan@xxxxxxxxx>
>
> For replica, filelock in LOCK_LOCK state doesn't allow Fc cap. So
> filelock in LOCK_SYNC_LOCK/LOCK_EXCL_LOCK state shouldn't allow Fc
> cap either.
>
> Replica can issue Fc cap only when filelock is in LOCK_SYNC state.
> Every time filelock changes to other state, replica need revoke Fc
> cap. This is slow, so I think it's better to not issue Fc cap from
> replica.
Can you separate out that behavior change from the bug fix?
I think it'll be a good idea for some workloads, but not others (and
possibly not most). Most files don't change, and being able to read them
via caps from a replica is important for making very hot shared
directories perform well.
If we do make the change, I think it should be controlled by a tunable.
Ideally, though, the MDS would infer some idea of whether this is a hot
file or not and decide that way. Like if the file was recently changed,
don't allow Fc, but if it is old, do?
sage
>
> Signed-off-by: Yan, Zheng <zheng.z.yan@xxxxxxxxx>
> ---
> src/mds/locks.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/src/mds/locks.c b/src/mds/locks.c
> index c7dd5be..542595a 100644
> --- a/src/mds/locks.c
> +++ b/src/mds/locks.c
> @@ -88,7 +88,7 @@ const struct sm_t sm_scatterlock = {
>
> const struct sm_state_t filelock[LOCK_MAX] = {
> // stable loner rep state r rp rd wr fwr l x caps(any,loner,xlocker,replica)
> - [LOCK_SYNC] = { 0, false, LOCK_SYNC, ANY, 0, ANY, 0, 0, ANY, 0, CEPH_CAP_GSHARED|CEPH_CAP_GCACHE|CEPH_CAP_GRD,0,0,CEPH_CAP_GSHARED|CEPH_CAP_GCACHE|CEPH_CAP_GRD },
> + [LOCK_SYNC] = { 0, false, LOCK_SYNC, ANY, 0, ANY, 0, 0, ANY, 0, CEPH_CAP_GSHARED|CEPH_CAP_GCACHE|CEPH_CAP_GRD,0,0,CEPH_CAP_GSHARED|CEPH_CAP_GRD },
> [LOCK_LOCK_SYNC] = { LOCK_SYNC, false, LOCK_LOCK, AUTH, 0, 0, 0, 0, 0, 0, CEPH_CAP_GCACHE,0,0,0 },
> [LOCK_EXCL_SYNC] = { LOCK_SYNC, true, LOCK_LOCK, 0, 0, 0, 0, XCL, 0, 0, 0,CEPH_CAP_GSHARED|CEPH_CAP_GCACHE|CEPH_CAP_GRD,0,0 },
> [LOCK_MIX_SYNC] = { LOCK_SYNC, false, LOCK_MIX_SYNC2,0,0, 0, 0, 0, 0, 0, CEPH_CAP_GRD|CEPH_CAP_GLAZYIO,0,0,CEPH_CAP_GRD },
> @@ -97,8 +97,8 @@ const struct sm_state_t filelock[LOCK_MAX] = {
> [LOCK_XSYN_SYNC] = { LOCK_SYNC, true, LOCK_LOCK, AUTH, 0, AUTH,0, 0, 0, 0, 0,CEPH_CAP_GCACHE,0,0 },
>
> [LOCK_LOCK] = { 0, false, LOCK_LOCK, AUTH, 0, REQ, AUTH,0, 0, 0, CEPH_CAP_GCACHE|CEPH_CAP_GBUFFER,0,0,0 },
> - [LOCK_SYNC_LOCK] = { LOCK_LOCK, false, LOCK_LOCK, AUTH, 0, REQ, 0, 0, 0, 0, CEPH_CAP_GCACHE,0,0,CEPH_CAP_GCACHE },
> - [LOCK_EXCL_LOCK] = { LOCK_LOCK, false, LOCK_LOCK, 0, 0, 0, 0, XCL, 0, 0, CEPH_CAP_GCACHE|CEPH_CAP_GBUFFER,0,0,CEPH_CAP_GCACHE },
> + [LOCK_SYNC_LOCK] = { LOCK_LOCK, false, LOCK_LOCK, AUTH, 0, REQ, 0, 0, 0, 0, CEPH_CAP_GCACHE,0,0,0 },
> + [LOCK_EXCL_LOCK] = { LOCK_LOCK, false, LOCK_LOCK, 0, 0, 0, 0, XCL, 0, 0, CEPH_CAP_GCACHE|CEPH_CAP_GBUFFER,0,0,0 },
> [LOCK_MIX_LOCK] = { LOCK_LOCK, false, LOCK_MIX, AUTH, 0, REQ, 0, 0, 0, 0, 0,0,0,0 },
> [LOCK_MIX_LOCK2] = { LOCK_LOCK, false, LOCK_LOCK, AUTH, 0, REQ, 0, 0, 0, 0, 0,0,0,0 },
>
> --
> 1.8.1.4
>
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