From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f69.google.com (mail-wm0-f69.google.com [74.125.82.69]) by kanga.kvack.org (Postfix) with ESMTP id 49E226B0292 for ; Thu, 31 Aug 2017 05:10:27 -0400 (EDT) Received: by mail-wm0-f69.google.com with SMTP id r75so3133093wmf.11 for ; Thu, 31 Aug 2017 02:10:27 -0700 (PDT) Received: from atrey.karlin.mff.cuni.cz (atrey.karlin.mff.cuni.cz. [195.113.26.193]) by mx.google.com with ESMTPS id v2si4653323wme.46.2017.08.31.02.10.25 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 31 Aug 2017 02:10:26 -0700 (PDT) Date: Thu, 31 Aug 2017 11:10:25 +0200 From: Pavel Machek Subject: Re: [RFC PATCH] treewide: remove GFP_TEMPORARY allocation flag Message-ID: <20170831091024.GB12920@amd> References: <20170728091904.14627-1-mhocko@kernel.org> <20170823175709.GA22743@xo-6d-61-c0.localdomain> <20170825063545.GA25498@dhcp22.suse.cz> <20170825072818.GA15494@amd> <20170825080442.GF25498@dhcp22.suse.cz> <20170825213936.GA13576@amd> <20170828123542.GJ17097@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="QKdGvSO+nmPlgiQ/" Content-Disposition: inline In-Reply-To: <20170828123542.GJ17097@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: linux-mm@kvack.org, Mel Gorman , Matthew Wilcox , Vlastimil Babka , Neil Brown , Theodore Ts'o , Andrew Morton , LKML --QKdGvSO+nmPlgiQ/ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > > > > You can define more exact meaning, and then adjust the usage. But > > > > there's no need to do treewide replacement... > > >=20 > > > I have checked most of them and except for the initially added onces = the > > > large portion where added without a good reasons or even break an > > > intuitive meaning by taking locks. > >=20 > > I don't see it. kmalloc() itself takes locks. Of course everyone takes > > locks. I don't think that's intuitive meaning. >=20 > I was talking about users of the flag. I have seen some to take a lock > right after they allocated GFP_TEMPORARY object. Yes, I'd expect people to take locks after allocating temporary objects. kmalloc itself takes locks. If the allocation is "usually" freed within miliseconds, that should be enough. > > > Seriously, if we need a short term semantic it should be clearly defi= ned > > > first. > >=20 > > "milliseconds, not hours." > >=20 > > > Is there any specific case why you think this patch is in a wrong > > > direction? E.g. a measurable regression? > >=20 > > Not playing that game. You should argue why it is improvement. And I > > don't believe you did. >=20 > Please read the whole changelog where I was quite verbose about how the > current flag is abused and how its semantic is weak and encourages a > wrong usage pattern. Moreover it is not even clear whether it helps > anything. I haven't seen any actual counter argument from you other than > "milliseconds not hours" without actually explaining how that would be > useful for any decisions done in the core MM layer. Well, I find that argumentation insufficient for global search&replace. Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --QKdGvSO+nmPlgiQ/ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlmn0oAACgkQMOfwapXb+vI1WgCgrLLQZGydVVIMREzWgbfJcZNW brgAnR2Zm8zGCxmfGTtSwVWSoIxCmSJZ =8kBv -----END PGP SIGNATURE----- --QKdGvSO+nmPlgiQ/-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org