Hello, Matthew. Matthew Wilcox wrote: >> It feels a bit too convoluted to me. sysfs is already pretty >> convoluted and adding yet more convolution would require pretty good >> justification, so I'm curious about the numbers. > > It is convoluted. The advantage of this is that we get to create many > fewer dirents. I wonder if we can do away with the dirents entirely, and > have dentries constructed dynamically instead. I think it's a bit misdirected. It's probably better to try to reduce the size of struct sysfs_dirent by tightly packing them and moving out dynamic part of the data structure into a separate one which is only allocated while the node is being accessed. The thing is that large number of the nodes would require struct sysfs_dirent anyway, so it would be much more benficial and less convoluted to diet the whole thing. In this particular case, the trade off is actually much worse because sysfs_dirent is being increased but the only one which is seeing any kind of memory usage drop is the new msi-x code. Given that there can be only a handful of msi-x controllers even in a fairly large system, I don't think memory usage will be reduced in any meaningful way even on affected systems and if you think about large systems with thousands and tens of thousands block devices, the bloat in sysfs_dirent will waste a lot of memory. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
