From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: [patch 1/4] raid1: directly dispatch write request if no bitmap Date: Thu, 24 May 2012 13:51:17 +1000 Message-ID: <20120524135117.238b2ed9@notabene.brown> References: <20120523072619.670179001@kernel.org> <20120523072829.967587288@kernel.org> <20120524122112.05b4d6e3@notabene.brown> <20120524025425.GA1190@kernel.org> <20120524130912.4076ea1a@notabene.brown> <20120524033126.GA1172@kernel.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/uk7tPxEDgHiOkzhg7/NM_MV"; protocol="application/pgp-signature" Return-path: In-Reply-To: <20120524033126.GA1172@kernel.org> Sender: linux-raid-owner@vger.kernel.org To: Shaohua Li Cc: linux-raid@vger.kernel.org, axboe@kernel.dk, shli@fusionio.com List-Id: linux-raid.ids --Sig_/uk7tPxEDgHiOkzhg7/NM_MV Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Thu, 24 May 2012 11:31:26 +0800 Shaohua Li wrote: > On Thu, May 24, 2012 at 01:09:12PM +1000, NeilBrown wrote: > > Not necessarily. It might queue it: > > if (current->bio_list) { > > bio_list_add(current->bio_list, bio); > > return; > > } >=20 > Ah, yes. Looks we can workaround it to increase bioset entry number to > raid_disks*2. There isn't too much memory wasted with it. No, that doesn't work. There might be raid_disk*2 separate threads which have each allocated on entry from the pool, and then they all block waiting for another. Adding the pool can change the probability of a deadlock but not the possibility. NeilBrown --Sig_/uk7tPxEDgHiOkzhg7/NM_MV Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iQIVAwUBT72wNTnsnt1WYoG5AQIj5w/8DUIdBEAW7TCd3qWaU1oiIyF2uZVNg1Om ugq6qjs7V7ZmWZgiswBbPm4b5RZRy7icltz+/GOMClKD6mbWuQSnx6hSgp2+2xVA Bn6vrVMQTexRN+/bPHD4MnU1s7cc9U0iE6cc7aOKgpu8rzpxAHHnDs3whDc4UdAx QChA60vAjR21vnWO5XqyL7Jf6wwiRbFrt5SkV7tZN1dGxvqCSdzqvFLwiOaZyzD7 GBgluSpULrnGC4r+lRmiPveWnwAiE+ldYERRet/6zqSdQ9yW0/O1DKWzDFnfE+NB rGdKp8Jm/KUoEOGaKL9AHAL7d1N/Pe410FnL7Qot+q3UwAwmG0bZhFDWtQEh4UCc zzLZZV3L+rlqrKiaK8yC+gY+aUN7KqhHqawafxj4oqgkes8UjQT/FlRFC4gVkwax 7zr8pYyHZzKtNoHGiapvdKP09w4xC+MNmpnbQT3VHFn4aWByufgvxIw507+0isFR e95OujX610ALsVldQe9OctPpe4NlTjaShprvtxUnwZ5Olwg5t5ZhMD5subkaYrmW Of9UVArB6NGt7dEhciRVRH8rfwAQnjkIjkYGIr+W7ig16qAYZtRkHw/Edq0fIlzd vEESqHr2bfeQfGpxyr2Jf2Bv+cfnc8qzqeXlmS0O3FLp4XIjXym0T3btcAcdE5Tz D9f0PUhsVes= =NZrx -----END PGP SIGNATURE----- --Sig_/uk7tPxEDgHiOkzhg7/NM_MV--