From 2aad2a86f6685c10360ec8a5a55eb9ab7059cb72 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 24 Sep 2014 13:31:50 -0400 Subject: percpu_ref: add PERCPU_REF_INIT_* flags With the recent addition of percpu_ref_reinit(), percpu_ref now can be used as a persistent switch which can be turned on and off repeatedly where turning off maps to killing the ref and waiting for it to drain; however, there currently isn't a way to initialize a percpu_ref in its off (killed and drained) state, which can be inconvenient for certain persistent switch use cases. Similarly, percpu_ref_switch_to_atomic/percpu() allow dynamic selection of operation mode; however, currently a newly initialized percpu_ref is always in percpu mode making it impossible to avoid the latency overhead of switching to atomic mode. This patch adds @flags to percpu_ref_init() and implements the following flags. * PERCPU_REF_INIT_ATOMIC : start ref in atomic mode * PERCPU_REF_INIT_DEAD : start ref killed and drained These flags should be able to serve the above two use cases. v2: target_core_tpg.c conversion was missing. Fixed. Signed-off-by: Tejun Heo Reviewed-by: Kent Overstreet Cc: Jens Axboe Cc: Christoph Hellwig Cc: Johannes Weiner --- fs/aio.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/aio.c') diff --git a/fs/aio.c b/fs/aio.c index 8d217ed04e6e..84a751005f5b 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -661,10 +661,10 @@ static struct kioctx *ioctx_alloc(unsigned nr_events) INIT_LIST_HEAD(&ctx->active_reqs); - if (percpu_ref_init(&ctx->users, free_ioctx_users, GFP_KERNEL)) + if (percpu_ref_init(&ctx->users, free_ioctx_users, 0, GFP_KERNEL)) goto err; - if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, GFP_KERNEL)) + if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, 0, GFP_KERNEL)) goto err; ctx->cpu = alloc_percpu(struct kioctx_cpu); -- cgit