From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f69.google.com (mail-pg0-f69.google.com [74.125.83.69]) by kanga.kvack.org (Postfix) with ESMTP id B851D6B0007 for ; Fri, 13 Apr 2018 10:28:25 -0400 (EDT) Received: by mail-pg0-f69.google.com with SMTP id z18so1634464pgc.20 for ; Fri, 13 Apr 2018 07:28:25 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id f15-v6si3989096pli.191.2018.04.13.07.28.24 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 13 Apr 2018 07:28:24 -0700 (PDT) Date: Fri, 13 Apr 2018 16:28:21 +0200 From: Michal Hocko Subject: Re: [PATCH 3/3] dcache: account external names as indirectly reclaimable memory Message-ID: <20180413142821.GW17484@dhcp22.suse.cz> References: <20180305133743.12746-1-guro@fb.com> <20180305133743.12746-5-guro@fb.com> <20180413133519.GA213834@rodete-laptop-imager.corp.google.com> <20180413135923.GT17484@dhcp22.suse.cz> <13f1f5b5-f3f8-956c-145a-4641fb996048@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <13f1f5b5-f3f8-956c-145a-4641fb996048@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka Cc: Minchan Kim , Roman Gushchin , linux-mm@kvack.org, Andrew Morton , Alexander Viro , Johannes Weiner , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com On Fri 13-04-18 16:20:00, Vlastimil Babka wrote: > On 04/13/2018 03:59 PM, Michal Hocko wrote: > > On Fri 13-04-18 22:35:19, Minchan Kim wrote: > >> On Mon, Mar 05, 2018 at 01:37:43PM +0000, Roman Gushchin wrote: > > [...] > >>> @@ -1614,9 +1623,11 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) > >>> name = &slash_name; > >>> dname = dentry->d_iname; > >>> } else if (name->len > DNAME_INLINE_LEN-1) { > >>> - size_t size = offsetof(struct external_name, name[1]); > >>> - struct external_name *p = kmalloc(size + name->len, > >>> - GFP_KERNEL_ACCOUNT); > >>> + struct external_name *p; > >>> + > >>> + reclaimable = offsetof(struct external_name, name[1]) + > >>> + name->len; > >>> + p = kmalloc(reclaimable, GFP_KERNEL_ACCOUNT); > >> > >> Can't we use kmem_cache_alloc with own cache created with SLAB_RECLAIM_ACCOUNT > >> if they are reclaimable? > > > > No, because names have different sizes and so we would basically have to > > duplicate many caches. > > We would need kmalloc-reclaimable-X variants. It could be worth it, > especially if we find more similar usages. I suspect they would be more > useful than the existing dma-kmalloc-X :) I am still not sure why __GFP_RECLAIMABLE cannot be made work as expected and account slab pages as SLAB_RECLAIMABLE -- Michal Hocko SUSE Labs