From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 96AFCC433F5 for ; Wed, 16 Feb 2022 14:58:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235276AbiBPO6f (ORCPT ); Wed, 16 Feb 2022 09:58:35 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:38620 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232406AbiBPO6e (ORCPT ); Wed, 16 Feb 2022 09:58:34 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4882A66FA2 for ; Wed, 16 Feb 2022 06:58:22 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E4C21618F7 for ; Wed, 16 Feb 2022 14:58:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D5DE6C004E1; Wed, 16 Feb 2022 14:58:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1645023501; bh=yQRaV08b6yYawP0//XFrE6u4IX1kHI9ZzRQ6l+MR24Y=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=d/LUJzvjI5mpBpeI2om/wg9YRUjKcN3rwg8oAQfYDzJhQrBMcgqc0weESbao8ctbr wDhH75XJQWEOH5T9laseJ/ZAjIKQ3LTwXx+X9mr7IarwSiiKHxY/NcnFjPMQiX9tdh PCZQsNEEQaC4cKP+4metft3gzIHmDZPiqygSXfmdUNITxXmLeeSnJFCNj0bLsvBZlO seFfc+VlMZNt5eTpdcTiPGGvENGAC7rvVG75cJ+3tB0cMiqcT4Z9bbQ2nqcxOo89Qt lEic2LLg53GV1rhE8YQ8UltwwuXplmxWm9HAFJcv/xtkbunE80K1gYgCJrIxFwiSsb Dz4sMj+ymqTOQ== Message-ID: <28350c955afc4f07030ba465cb492605bf5889da.camel@kernel.org> Subject: Re: [PATCH 1/3] ceph: move to a dedicated slabcache for ceph_cap_snap From: Jeff Layton To: xiubli@redhat.com Cc: idryomov@gmail.com, vshankar@redhat.com, ceph-devel@vger.kernel.org Date: Wed, 16 Feb 2022 09:58:19 -0500 In-Reply-To: <20220215122316.7625-2-xiubli@redhat.com> References: <20220215122316.7625-1-xiubli@redhat.com> <20220215122316.7625-2-xiubli@redhat.com> Content-Type: text/plain; charset="ISO-8859-15" User-Agent: Evolution 3.42.3 (3.42.3-1.fc35) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org On Tue, 2022-02-15 at 20:23 +0800, xiubli@redhat.com wrote: > From: Xiubo Li > > There could be huge number of capsnap queued in a short time, on > x86_64 it's 248 bytes, which will be rounded up to 256 bytes by > kzalloc. Move this to a dedicated slabcache to save 8 bytes for > each. > > For the kmalloc-256 slab cache, the actual size will be 512 bytes: > kmalloc-256 21797 74656 512 32 4 : tunables, etc > > For a dedicated slab cache the real size is 312 bytes: > ceph_cap_snap 0 0 312 52 4 : tunables, etc > > So actually we can save 200 bytes for each. > I dropped everything but the top paragraph in the description above. On non-debug kernels, kmalloc-256 is indeed 256 bytes. The inflation you're seeing is almost certainly from sort of kernel debugging options. > Signed-off-by: Xiubo Li > --- > fs/ceph/snap.c | 5 +++-- > fs/ceph/super.c | 7 +++++++ > fs/ceph/super.h | 2 +- > include/linux/ceph/libceph.h | 1 + > 4 files changed, 12 insertions(+), 3 deletions(-) > > diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c > index b41e6724c591..c787775eaf2a 100644 > --- a/fs/ceph/snap.c > +++ b/fs/ceph/snap.c > @@ -482,7 +482,7 @@ static void ceph_queue_cap_snap(struct ceph_inode_info *ci) > struct ceph_buffer *old_blob = NULL; > int used, dirty; > > - capsnap = kzalloc(sizeof(*capsnap), GFP_NOFS); > + capsnap = kmem_cache_alloc(ceph_cap_snap_cachep, GFP_NOFS); > if (!capsnap) { > pr_err("ENOMEM allocating ceph_cap_snap on %p\n", inode); > return; > @@ -603,7 +603,8 @@ static void ceph_queue_cap_snap(struct ceph_inode_info *ci) > spin_unlock(&ci->i_ceph_lock); > > ceph_buffer_put(old_blob); > - kfree(capsnap); > + if (capsnap) > + kmem_cache_free(ceph_cap_snap_cachep, capsnap); > ceph_put_snap_context(old_snapc); > } > > diff --git a/fs/ceph/super.c b/fs/ceph/super.c > index bf79f369aec6..978463fa822c 100644 > --- a/fs/ceph/super.c > +++ b/fs/ceph/super.c > @@ -864,6 +864,7 @@ static void destroy_fs_client(struct ceph_fs_client *fsc) > */ > struct kmem_cache *ceph_inode_cachep; > struct kmem_cache *ceph_cap_cachep; > +struct kmem_cache *ceph_cap_snap_cachep; > struct kmem_cache *ceph_cap_flush_cachep; > struct kmem_cache *ceph_dentry_cachep; > struct kmem_cache *ceph_file_cachep; > @@ -892,6 +893,9 @@ static int __init init_caches(void) > ceph_cap_cachep = KMEM_CACHE(ceph_cap, SLAB_MEM_SPREAD); > if (!ceph_cap_cachep) > goto bad_cap; > + ceph_cap_snap_cachep = KMEM_CACHE(ceph_cap_snap, SLAB_MEM_SPREAD); > + if (!ceph_cap_snap_cachep) > + goto bad_cap_snap; > ceph_cap_flush_cachep = KMEM_CACHE(ceph_cap_flush, > SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD); > if (!ceph_cap_flush_cachep) > @@ -931,6 +935,8 @@ static int __init init_caches(void) > bad_dentry: > kmem_cache_destroy(ceph_cap_flush_cachep); > bad_cap_flush: > + kmem_cache_destroy(ceph_cap_snap_cachep); > +bad_cap_snap: > kmem_cache_destroy(ceph_cap_cachep); > bad_cap: > kmem_cache_destroy(ceph_inode_cachep); > @@ -947,6 +953,7 @@ static void destroy_caches(void) > > kmem_cache_destroy(ceph_inode_cachep); > kmem_cache_destroy(ceph_cap_cachep); > + kmem_cache_destroy(ceph_cap_snap_cachep); > kmem_cache_destroy(ceph_cap_flush_cachep); > kmem_cache_destroy(ceph_dentry_cachep); > kmem_cache_destroy(ceph_file_cachep); > diff --git a/fs/ceph/super.h b/fs/ceph/super.h > index c0718d5a8fb8..2d08104c8955 100644 > --- a/fs/ceph/super.h > +++ b/fs/ceph/super.h > @@ -231,7 +231,7 @@ static inline void ceph_put_cap_snap(struct ceph_cap_snap *capsnap) > if (refcount_dec_and_test(&capsnap->nref)) { > if (capsnap->xattr_blob) > ceph_buffer_put(capsnap->xattr_blob); > - kfree(capsnap); > + kmem_cache_free(ceph_cap_snap_cachep, capsnap); > } > } > > diff --git a/include/linux/ceph/libceph.h b/include/linux/ceph/libceph.h > index edf62eaa6285..00af2c98da75 100644 > --- a/include/linux/ceph/libceph.h > +++ b/include/linux/ceph/libceph.h > @@ -284,6 +284,7 @@ DEFINE_RB_LOOKUP_FUNC(name, type, keyfld, nodefld) > > extern struct kmem_cache *ceph_inode_cachep; > extern struct kmem_cache *ceph_cap_cachep; > +extern struct kmem_cache *ceph_cap_snap_cachep; > extern struct kmem_cache *ceph_cap_flush_cachep; > extern struct kmem_cache *ceph_dentry_cachep; > extern struct kmem_cache *ceph_file_cachep; -- Jeff Layton