From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZq4ix9CMBb+1+7HNxuiOzNseNFDKrbsFTzgf8+LhAKfd05cl238VeYq1UG5nVmwhQeiaUQg ARC-Seal: i=1; a=rsa-sha256; t=1525148396; cv=none; d=google.com; s=arc-20160816; b=FOMElfxt7cw+qgNXkR3kdfwfUAGV5nu7bIW6tzyUeePNIaWMPIALDC+8AdAMcyUpV9 XKz9vTrfFyy/Km9x3tnaG+etg0J7cWuixTyDGjTgXbRUnVXySAjVxrYv4m2d/IV2v9dR eQ7sZVXgCmK51BPlqQ+GXaYKxtkWQtINf+IsLg9Hiyw7c5c88rcpHe07G1P/7oTQNLZu 7j5go/OvsXyhmg3ikhfcfu/S/QLR4uRc+BqQQ58J/5rY53OtbjBGMk7NhdJRodwEtut6 HWymLS6qRKx79kBztuzpehYW+PxHEAWfSHck6lGsTPFMtU5wgG/NztwwvOSvh707GbhR sZnA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:content-transfer-encoding:content-id:content-language :accept-language:in-reply-to:references:message-id:date:thread-index :thread-topic:subject:cc:to:from:arc-authentication-results; bh=q5hSnxNAZELDREAQHHZvEEZ31zoLaQKaHiVQ+Vf36ds=; b=lxkHHmy6vRIJU7mHe1B+c5XeMm1BxpA4efw7TCJ/gnbQ6VvWNMbomAa6boPZ4CWMOK 3Pv8eLahtaI1MbcM1oYztkNXfOcyPaGFBl7vn0f+YM52/8i/sFOn3kzr14lyCrpRSvkb anzO4AcfAg407nrbkTPbJF+fEXQ3S4gURb3jw9qdXC0TYQObF7BZGr1SmcwPdAeCxbnJ wHS6WVzLBgnYDjzwIoa2Cj4asXIiH3qrqldXo5ezI5OZMqzFCS1cZ10FR3E3QN/Qm44R of0MdG8OXogyOL1tnTJN9DDGxZvX1HFz8Ip7GaELtTxLxdZKChlU1XK4Ep9XOWV3WHz6 9nhw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of andreas.dilger@intel.com designates 134.134.136.20 as permitted sender) smtp.mailfrom=andreas.dilger@intel.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of andreas.dilger@intel.com designates 134.134.136.20 as permitted sender) smtp.mailfrom=andreas.dilger@intel.com X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,349,1520924400"; d="scan'208";a="54962337" From: "Dilger, Andreas" To: NeilBrown CC: "Drokin, Oleg" , Greg Kroah-Hartman , James Simmons , "Linux Kernel Mailing List" , Lustre Development List Subject: Re: [PATCH 03/10] staging: lustre: lu_object: discard extra lru count. Thread-Topic: [PATCH 03/10] staging: lustre: lu_object: discard extra lru count. Thread-Index: AQHT4P/2AaK69p/2O0ySpUfCQOIv8KQauqeA Date: Tue, 1 May 2018 04:19:54 +0000 Message-ID: References: <152514658325.17843.11455067361317157487.stgit@noble> <152514675893.17843.8396665070911641266.stgit@noble> In-Reply-To: <152514675893.17843.8396665070911641266.stgit@noble> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.252.137.157] Content-Type: text/plain; charset="us-ascii" Content-ID: <8CBB530FEF2EA04D8B612C526B2B58BC@intel.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1599232334415255756?= X-GMAIL-MSGID: =?utf-8?q?1599234004557837770?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Apr 30, 2018, at 21:52, NeilBrown wrote: >=20 > lu_object maintains 2 lru counts. > One is a per-bucket lsb_lru_len. > The other is the per-cpu ls_lru_len_counter. >=20 > The only times the per-bucket counters are use are: > - a debug message when an object is added > - in lu_site_stats_get when all the counters are combined. >=20 > The debug message is not essential, and the per-cpu counter > can be used to get the combined total. >=20 > So discard the per-bucket lsb_lru_len. >=20 > Signed-off-by: NeilBrown Looks reasonable, though it would also be possible to fix the percpu functions rather than adding a workaround in this code. Reviewed-by: Andreas Dilger > --- > drivers/staging/lustre/lustre/obdclass/lu_object.c | 24 ++++++++-------= ----- > 1 file changed, 9 insertions(+), 15 deletions(-) >=20 > diff --git a/drivers/staging/lustre/lustre/obdclass/lu_object.c b/drivers= /staging/lustre/lustre/obdclass/lu_object.c > index 2a8a25d6edb5..2bf089817157 100644 > --- a/drivers/staging/lustre/lustre/obdclass/lu_object.c > +++ b/drivers/staging/lustre/lustre/obdclass/lu_object.c > @@ -57,10 +57,6 @@ > #include >=20 > struct lu_site_bkt_data { > - /** > - * number of object in this bucket on the lsb_lru list. > - */ > - long lsb_lru_len; > /** > * LRU list, updated on each access to object. Protected by > * bucket lock of lu_site::ls_obj_hash. > @@ -187,10 +183,9 @@ void lu_object_put(const struct lu_env *env, struct = lu_object *o) > if (!lu_object_is_dying(top)) { > LASSERT(list_empty(&top->loh_lru)); > list_add_tail(&top->loh_lru, &bkt->lsb_lru); > - bkt->lsb_lru_len++; > percpu_counter_inc(&site->ls_lru_len_counter); > - CDEBUG(D_INODE, "Add %p to site lru. hash: %p, bkt: %p, lru_len: %ld\n= ", > - o, site->ls_obj_hash, bkt, bkt->lsb_lru_len); > + CDEBUG(D_INODE, "Add %p to site lru. hash: %p, bkt: %p\n", > + o, site->ls_obj_hash, bkt); > cfs_hash_bd_unlock(site->ls_obj_hash, &bd, 1); > return; > } > @@ -238,7 +233,6 @@ void lu_object_unhash(const struct lu_env *env, struc= t lu_object *o) >=20 > list_del_init(&top->loh_lru); > bkt =3D cfs_hash_bd_extra_get(obj_hash, &bd); > - bkt->lsb_lru_len--; > percpu_counter_dec(&site->ls_lru_len_counter); > } > cfs_hash_bd_del_locked(obj_hash, &bd, &top->loh_hash); > @@ -422,7 +416,6 @@ int lu_site_purge_objects(const struct lu_env *env, s= truct lu_site *s, > cfs_hash_bd_del_locked(s->ls_obj_hash, > &bd2, &h->loh_hash); > list_move(&h->loh_lru, &dispose); > - bkt->lsb_lru_len--; > percpu_counter_dec(&s->ls_lru_len_counter); > if (did_sth =3D=3D 0) > did_sth =3D 1; > @@ -621,7 +614,6 @@ static struct lu_object *htable_lookup(struct lu_site= *s, > lprocfs_counter_incr(s->ls_stats, LU_SS_CACHE_HIT); > if (!list_empty(&h->loh_lru)) { > list_del_init(&h->loh_lru); > - bkt->lsb_lru_len--; > percpu_counter_dec(&s->ls_lru_len_counter); > } > return lu_object_top(h); > @@ -1834,19 +1826,21 @@ struct lu_site_stats { > unsigned int lss_busy; > }; >=20 > -static void lu_site_stats_get(struct cfs_hash *hs, > +static void lu_site_stats_get(const struct lu_site *s, > struct lu_site_stats *stats, int populated) > { > + struct cfs_hash *hs =3D s->ls_obj_hash; > struct cfs_hash_bd bd; > unsigned int i; > + /* percpu_counter_read_positive() won't accept a const pointer */ > + struct lu_site *s2 =3D (struct lu_site *)s; It would seem worthwhile to change the percpu_counter_read_positive() and percpu_counter_read() arguments to be "const struct percpu_counter *fbc", rather than doing this cast here. I can't see any reason that would be bad= , since both implementations just access fbc->count, and do not modify anythi= ng. > + stats->lss_busy +=3D cfs_hash_size_get(hs) - > + percpu_counter_read_positive(&s2->ls_lru_len_counter); > cfs_hash_for_each_bucket(hs, &bd, i) { > - struct lu_site_bkt_data *bkt =3D cfs_hash_bd_extra_get(hs, &bd); > struct hlist_head *hhead; >=20 > cfs_hash_bd_lock(hs, &bd, 1); > - stats->lss_busy +=3D > - cfs_hash_bd_count_get(&bd) - bkt->lsb_lru_len; > stats->lss_total +=3D cfs_hash_bd_count_get(&bd); > stats->lss_max_search =3D max((int)stats->lss_max_search, > cfs_hash_bd_depmax_get(&bd)); > @@ -2039,7 +2033,7 @@ int lu_site_stats_print(const struct lu_site *s, st= ruct seq_file *m) > struct lu_site_stats stats; >=20 > memset(&stats, 0, sizeof(stats)); > - lu_site_stats_get(s->ls_obj_hash, &stats, 1); > + lu_site_stats_get(s, &stats, 1); >=20 > seq_printf(m, "%d/%d %d/%ld %d %d %d %d %d %d %d\n", > stats.lss_busy, >=20 >=20 Cheers, Andreas -- Andreas Dilger Lustre Principal Architect Intel Corporation