From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Maxim V. Patlasov" Subject: Re: [fuse-devel] [PATCH 14/14] mm: Account for WRITEBACK_TEMP in balance_dirty_pages Date: Thu, 25 Apr 2013 18:29:58 +0400 Message-ID: <51793DE6.3000503@parallels.com> References: <20130401103749.19027.89833.stgit@maximpc.sw.ru> <20130401104250.19027.27795.stgit@maximpc.sw.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: , , "fuse-devel@lists.sourceforge.net" , , , , , , , To: "miklos@szeredi.hu" Return-path: In-Reply-To: <20130401104250.19027.27795.stgit@maximpc.sw.ru> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Hi Miklos, 04/01/2013 02:42 PM, Maxim V. Patlasov =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > Make balance_dirty_pages start the throttling when the WRITEBACK_TEMP > counter is high enough. This prevents us from having too many dirty > pages on fuse, thus giving the userspace part of it a chance to write > stuff properly. > > Note, that the existing balance logic is per-bdi, i.e. if the fuse > user task gets stuck in the function this means, that it either > writes to the mountpoint it serves (but it can deadlock even without > the writeback) or it is writing to some _other_ dirty bdi and in the > latter case someone else will free the memory for it. > > Signed-off-by: Maxim Patlasov > Signed-off-by: Pavel Emelyanov > --- > mm/page-writeback.c | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index 0713bfb..c47bcd4 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -1235,7 +1235,8 @@ static void balance_dirty_pages(struct address_= space *mapping, > */ > nr_reclaimable =3D global_page_state(NR_FILE_DIRTY) + > global_page_state(NR_UNSTABLE_NFS); > - nr_dirty =3D nr_reclaimable + global_page_state(NR_WRITEBACK); > + nr_dirty =3D nr_reclaimable + global_page_state(NR_WRITEBACK) + > + global_page_state(NR_WRITEBACK_TEMP); > =20 > global_dirty_limits(&background_thresh, &dirty_thresh); Please drop this patch. As we discussed in LSF/MM, the fix above is=20 correct, but it's not enough: we also need to ensure disregard of=20 NR_WRITEBACK_TEMP when balance_dirty_pages() is called from fuse daemon= =2E=20 I'll send a separate patch-set soon. Thanks, Maxim