From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mathieu Desnoyers Subject: Re: [PATCH v7 06/16] tracepoint: use new hashtable implementation Date: Mon, 29 Oct 2012 07:35:15 -0400 Message-ID: <20121029113515.GB9115@Krystal> References: <1351450948-15618-1-git-send-email-levinsasha928@gmail.com> <1351450948-15618-6-git-send-email-levinsasha928@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Cc: torvalds@linux-foundation.org, tj@kernel.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, paul.gortmaker@windriver.com, davem@davemloft.net, rostedt@goodmis.org, mingo@elte.hu, ebiederm@xmission.com, aarcange@redhat.com, ericvh@gmail.com, netdev@vger.kernel.org, josh@joshtriplett.org, eric.dumazet@gmail.com, axboe@kernel.dk, agk@redhat.com, dm-devel@redhat.com, neilb@suse.de, ccaulfie@redhat.com, teigland@redhat.com, Trond.Myklebust@netapp.com, bfields@fieldses.org, fweisbec@gmail.com, jesse@nicira.com, venkat.x.venkatsubra@oracle.com, ejt@redhat.com, snitzer@redhat.com, edumazet@google.com, linux-nfs@vger.kernel.org, dev@openvswitch.org, rds-devel@oss.oracle.com, lw@cn.fujitsu.com To: Sasha Levin Return-path: Content-Disposition: inline In-Reply-To: <1351450948-15618-6-git-send-email-levinsasha928@gmail.com> Sender: owner-linux-mm@kvack.org List-Id: netdev.vger.kernel.org * Sasha Levin (levinsasha928@gmail.com) wrote: > Switch tracepoints to use the new hashtable implementation. This reduces = the amount of > generic unrelated code in the tracepoints. >=20 > Signed-off-by: Sasha Levin > --- > kernel/tracepoint.c | 27 +++++++++++---------------- > 1 file changed, 11 insertions(+), 16 deletions(-) >=20 > diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c > index d96ba22..854df92 100644 > --- a/kernel/tracepoint.c > +++ b/kernel/tracepoint.c > @@ -26,6 +26,7 @@ > #include > #include > #include > +#include > =20 > extern struct tracepoint * const __start___tracepoints_ptrs[]; > extern struct tracepoint * const __stop___tracepoints_ptrs[]; > @@ -49,8 +50,7 @@ static LIST_HEAD(tracepoint_module_list); > * Protected by tracepoints_mutex. > */ > #define TRACEPOINT_HASH_BITS 6 > -#define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) > -static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; > +static DEFINE_HASHTABLE(tracepoint_table, TRACEPOINT_HASH_BITS); > =20 [...] > =20 > @@ -722,6 +715,8 @@ struct notifier_block tracepoint_module_nb =3D { > =20 > static int init_tracepoints(void) > { > + hash_init(tracepoint_table); > + > return register_module_notifier(&tracepoint_module_nb); > } > __initcall(init_tracepoints); So we have a hash table defined in .bss (therefore entirely initialized to NULL), and you add a call to "hash_init", which iterates on the whole array and initialize it to NULL (again) ? This extra initialization is redundant. I think it should be removed =66rom here, and hashtable.h should document that hash_init() don't need to be called on zeroed memory (which includes static/global variables, kzalloc'd memory, etc). Thanks, Mathieu --=20 Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org