From d835502f3dacad1638d516ab156d66f0ba377cf5 Mon Sep 17 00:00:00 2001
From: Shaohua Li <shli@kernel.org>
Date: Tue, 31 Dec 2013 11:38:27 +0800
Subject: [PATCH] percpu_ida: fix a live lock

steal_tags only happens when free tags is more than half of the total
tags.  This is too strict and can cause live lock. I found that if one
cpu has free tags, but other cpu can't steal (thread is bound to
specific cpus), threads which want to allocate tags are always
sleeping. I found this when I run next patch, but this could happen
without it I think.

I did performance test too with null_blk. Two cases (each cpu has enough
percpu tags, or total tags are limited), no performance changes were
observed.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
Reading git-format-patch failed