Linus Torvalds <[EMAIL PROTECTED]> wrote: > > > > On Sun, 28 Aug 2005, James Bottomley wrote: > > > > radix_tree_insert() is reliable from IRQ provided you don't try to use > > radix_tree_preload() and you defined your radix tree gfp flag to be > > GFP_ATOMIC. > > It would be better if it wasn't, though.
There's nothing in radix-tree which forces this: it requires caller-provided locking. > I really don't see why we made it irq-safe, and take the hit of disabling > interrupts in addition to the locking. That's a quite noticeable loss, > and I don't think it's really a valid thing to insert (or look up) page > cache entries from interrupts. > > What _is_ it that makes us do that, btw? Is it just because we clear the > writeback tag bits or something? Sad. It makes page lookup noticeably more > expensive. Yes, address_space.tree_lock was made IRQ-safe so we could alter the tree's tags from disk completions. Presumably Nick's lockless pagecache stuff removes that. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/