Messages in this thread | | | Date | Tue, 24 Jul 2018 09:49:20 +0800 | From | Wei Wang <> | Subject | Re: [PATCH v36 2/5] virtio_balloon: replace oom notifier with shrinker |
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On 07/23/2018 10:13 PM, Michael S. Tsirkin wrote: >>> vb->vb_dev_info.inode->i_mapping->a_ops = &balloon_aops; >>> #endif >>> + err = virtio_balloon_register_shrinker(vb); >>> + if (err) >>> + goto out_del_vqs; >>> So we can get scans before device is ready. Leak will fail >>> then. Why not register later after device is ready? >> Probably no. >> >> - it would be better not to set device ready when register_shrinker failed. > That's very rare so I won't be too worried.
Just a little confused with the point here. "very rare" means it still could happen (even it's a corner case), and if that happens, we got something wrong functionally. So it will be a bug if we change like that, right?
Still couldn't understand the reason of changing shrinker_register after device_ready (the original oom notifier was registered before setting device ready too)? (I think the driver won't get shrinker_scan called if device isn't ready because of the reasons below)
>> - When the device isn't ready, ballooning won't happen, that is, >> vb->num_pages will be 0, which results in shrinker_count=0 and shrinker_scan >> won't be called.
Best, Wei
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