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Goncalves" , Andrew Morton , Mel Gorman , Michal Hocko , Thomas Gleixner , John Ogness Subject: Re: [PATCH] mm/page_alloc: Use write_seqlock_irqsave() instead write_seqlock() + local_irq_save(). Message-ID: <20230623132437.Ejno8pej@linutronix.de> References: <20230621104034.HT6QnNkQ@linutronix.de> <0e9fc992-8e05-2e63-b3b1-d8d3ce89fc16@I-love.SAKURA.ne.jp> <20230621130641.-5iueY1I@linutronix.de> <20230621143421.BgHjJklo@linutronix.de> <20230623081250.h20rlLik@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: X-Rspamd-Queue-Id: E33668001C X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: 5f4rq4okamjrheynduhzwdarsztg1odp X-HE-Tag: 1687526680-113147 X-HE-Meta: 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 lSUoLhnk lQVsnCDQWKllxEzXyr/JXVBdnGMjDDSTpIB8Cmxoi0gFCTHjyQ9mPuwPyUGORg9sNuny3r4D25bAqzeX61rx9K/gLjKizLdAOtQcgpWI0macATnxbUKEalpxkbjSXH/xpCxGGTZqFLVhFj6w= 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 2023-06-23 12:40:24 [+0200], Petr Mladek wrote: > > but I would rather suggest lockdep annotation instead of disabling > > either preemption or migration. If I read the comment on top right, this > > API isn't open for the public. >=20 > It might work when mm people agree to explicitly call > migrate_disable() in __build_all_zonelists(). I mean > to call there: >=20 > migrate_disable(); > printk_deferred_enter(); > write_seqlock_irqsave(&zonelist_update_seq, flags); >=20 > Plus it would require some comments. right but I wanted to move it after write_seqlock_irqsave(). > > To be honst, I would suggest to work towards always printing in a thread > > with an emergency console than this deferred/ safe duckt tape. >=20 > I have used this argument many years. But it is not much convincing > after 10 years. Note that John has sent 1st RFC 4 years ago and we > still do not have the kthreads :-/ Yes, it makes me very sad. It feels longer than that. We have in RT ever since=E2=80=A6 > Best Regards, > Petr Sebastian