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Thu, 21 Oct 2021 10:13:39 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id jhdbBFM9cWHWRQAAMHmgww (envelope-from ); Thu, 21 Oct 2021 10:13:39 +0000 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 From: "NeilBrown" To: "Uladzislau Rezki" Cc: "Michal Hocko" , "Michal Hocko" , "Linux Memory Management List" , "Dave Chinner" , "Andrew Morton" , "Christoph Hellwig" , linux-fsdevel@vger.kernel.org, "LKML" , "Ilya Dryomov" , "Jeff Layton" Subject: Re: [RFC 2/3] mm/vmalloc: add support for __GFP_NOFAIL In-reply-to: <20211020192430.GA1861@pc638.lan> References: <20211018114712.9802-3-mhocko@kernel.org>, <20211019110649.GA1933@pc638.lan>, , <20211019194658.GA1787@pc638.lan>, , , , , , , <20211020192430.GA1861@pc638.lan> Date: Thu, 21 Oct 2021 21:13:35 +1100 Message-id: <163481121586.17149.4002493290882319236@noble.neil.brown.name> X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 03C5CB0000A2 X-Stat-Signature: 9pogqqyppps6ym8xcgnpu4c9bqeo7qab Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=LfqQc63I; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=H2XjTRNO; dmarc=pass (policy=none) header.from=suse.de; spf=pass (imf24.hostedemail.com: domain of neilb@suse.de designates 195.135.220.28 as permitted sender) smtp.mailfrom=neilb@suse.de X-HE-Tag: 1634811221-154294 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, 21 Oct 2021, Uladzislau Rezki wrote: > On Wed, Oct 20, 2021 at 05:00:28PM +0200, Uladzislau Rezki wrote: > > > > > > On Wed 20-10-21 16:29:14, Uladzislau Rezki wrote: > > > > On Wed, Oct 20, 2021 at 4:06 PM Michal Hocko wrote: > > > [...] > > > > > As I've said I am OK with either of the two. Do you or anybody have= any > > > > > preference? Without any explicit event to wake up for neither of th= e two > > > > > is more than just an optimistic retry. > > > > > > > > > From power perspective it is better to have a delay, so i tend to say > > > > that delay is better. > > > > > > I am a terrible random number generator. Can you give me a number > > > please? > > > > > Well, we can start from one jiffy so it is one timer tick: schedule_timeo= ut(1) > >=20 > A small nit, it is better to replace it by the simple msleep() call: msleep= (jiffies_to_msecs(1)); I disagree. I think schedule_timeout_uninterruptible(1) is the best wait to sleep for 1 ticl msleep() contains timeout =3D msecs_to_jiffies(msecs) + 1; and both jiffies_to_msecs and msecs_to_jiffies might round up too. So you will sleep for at least twice as long as you asked for, possible more. NeilBrown >=20 > -- > Vlad Rezki >=20 >=20