Re: [RFC PATCH v1 15/17] blk-cgroup: remove blkg radix tree preloading
Christoph Hellwig <[email protected]> Thu, 9 Jul 2026 08:18:37 +0200
| Newsgroups | org.kernel.vger.linux-bcache,dev.linux.lists.dm-devel,org.infradead.lists.linux-nvme,org.kernel.vger.cgroups,org.kernel.vger.linux-block |
|---|---|
| Message-ID | <[email protected]> |
On Sun, Jul 05, 2026 at 03:51:22AM +0800, Yu Kuai wrote: > From: Yu Kuai <[email protected]> > > blkg creation is now serialized by q->blkcg_mutex and no longer runs > under q->queue_lock. The radix tree is initialized with GFP_NOWAIT, so > radix_tree_insert() cannot sleep while blkcg->lock is held and the old > preload dance is no longer needed. > > Remove the preload calls and the associated unwind path. Isn't the GFP_NOWAIT a bit of a problem because it can fail way too easy? What about converting both the radix tree and list to an xarray using the internal xarray to deal with sleeping allocations?