Messages in this thread | | | From | Jeff Moyer <> | Subject | Re: [PATCH] aio: Save a few cycles in 'lookup_ioctx()' | Date | Mon, 15 Aug 2022 14:10:49 -0400 |
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Christophe JAILLET <christophe.jaillet@wanadoo.fr> writes:
> Le 03/11/2021 à 22:31, Christophe JAILLET a écrit : >> Use 'percpu_ref_tryget_live_rcu()' instead of 'percpu_ref_tryget_live()' to >> save a few cycles when it is known that the rcu lock is already >> taken/released. >> >> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> >> --- >> fs/aio.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/fs/aio.c b/fs/aio.c >> index 9c81cf611d65..d189ea13e10a 100644 >> --- a/fs/aio.c >> +++ b/fs/aio.c >> @@ -1062,7 +1062,7 @@ static struct kioctx *lookup_ioctx(unsigned long ctx_id) >> id = array_index_nospec(id, table->nr); >> ctx = rcu_dereference(table->table[id]); >> if (ctx && ctx->user_id == ctx_id) { >> - if (percpu_ref_tryget_live(&ctx->users)) >> + if (percpu_ref_tryget_live_rcu(&ctx->users)) >> ret = ctx; >> } >> out: > > > Hi, > gentle reminder. > > Is this patch useful? > When I first posted it, percpu_ref_tryget_live_rcu() was really new. > Now it is part of linux since 5.16. > > Saving a few cycles in a function with "lookup" in its name looks > always good to me.
The patch looks fine to me.
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
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