On Wed, 29 Nov 2023, Oleg Nesterov wrote: > On 11/28, NeilBrown wrote: > > > > I have evidence from a customer site of 256 nfsd threads adding files to > > delayed_fput_lists nearly twice as fast they are retired by a single > > work-queue thread running delayed_fput(). As you might imagine this > > does not end well (20 million files in the queue at the time a snapshot > > was taken for analysis). > > On a related note... Neil, Al, et al, can you look at > > [PATCH 1/3] fput: don't abuse task_work_add() when possible > https://lore.kernel.org/all/20150908171446.GA14589@xxxxxxxxxx/ > Would it make sense to create a separate task_struct->delayed_fput llist? fput() adds the file to this llist and if it was the first item on the list, it then adds the task_work. That would probably request adding a callback_head to struct task_struct as well. NeilBrown
