I think it’s used to stop that cache object from being frozen. so that it won’t be exported to other MDS. Regards, Dongdong > 在 2018年2月8日，下午3:19，Xuehan Xu <xxhdx1985126@xxxxxxxxx> 写道： > > On 8 February 2018 at 15:10, Xuehan Xu <xxhdx1985126@xxxxxxxxx> wrote: >> Hi, everyone. >> >> Actually, in our case, the whole procedure of a single run of >> "getattr" ops processing is this: >> >> 1. The "finish" phase of the previous "getattr" op processing turn the >> target inode's filelock state into LOCK_SYNC_MIX if its current state >> is LOCK_SYNC; >> 2. mds blocks all other "getattr" operations when the target inode's >> filelock state is LOCK_SYNC_MIX, and wait for all clients to release >> caps that are not allowed in LOCK_MIX; >> 3. When all clients release those not allowed caps, the inode's >> filelock state is turned in to LOCK_MIX; >> 4. A new "getattr" op is dispatched to be processed, during which the >> inode's filelock state is turned back to LOCK_SYNC and the "getattr" >> op is processed successfully; >> >> If the next op that is to be dispatched to be processed is, again, a >> "getattr", the whole procedure would be repeated. In our case, the >> waiting of the mds for all clients to release caps that are not >> allowed in state LOCK_MIX could take several hundreds of milliseconds, >> which means only a few "getattr" requests can be processed per second. >> And because the "getattr" operation is the mostly issued request in >> our case, the above procedure can repeat so many times that the >> response time of the process of a single "getattr" request can take >> 40+ seconds as they have to wait for their previous "getattr" ops to >> be processed first, and in the meantime, the "setattr" operations that >> are issued by the writing client can hardly get the chance to be >> processed > > I'm now trying to read the related source code, however, I found it a > little hard to understand. > What does the MDSCacheObject's auth_pin method mean? Does it mean that > the MDSCacheObject cannot be evicted from the in memory cache? > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
