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dmarc=pass (policy=none) header.from=oracle.com; spf=none (imf23.hostedemail.com: domain of ankur.a.arora@oracle.com has no SPF policy when checking 205.220.165.32) smtp.mailfrom=ankur.a.arora@oracle.com; arc=pass ("microsoft.com:s=arcselector9901:i=1") X-Rspam-User: Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2021-07-09 header.b=xCfbtyFB; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=pfxZ8Xq4; dmarc=pass (policy=none) header.from=oracle.com; spf=none (imf23.hostedemail.com: domain of ankur.a.arora@oracle.com has no SPF policy when checking 205.220.165.32) smtp.mailfrom=ankur.a.arora@oracle.com; arc=pass ("microsoft.com:s=arcselector9901:i=1") X-Rspamd-Server: rspam03 X-Stat-Signature: qs5ebfjy9z895yj1jha4crn1k44n3ohj X-Rspamd-Queue-Id: E6BD114004D X-HE-Tag: 1654719731-548286 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: Linus Torvalds writes: > On Wed, Jun 8, 2022 at 12:25 PM Ankur Arora wrote: >> >> But, even on x86, AFAICT gigantic pages could straddle MAX_SECTION_BITS? >> An arch specific clear_huge_page() code could, however handle 1GB pages >> via some kind of static loop around (30 - MAX_SECTION_BITS). > > Even if gigantic pages straddle that area, it simply shouldn't matter. > > The only reason that MAX_SECTION_BITS matters is for the 'struct page *' lookup. > > And the only reason for *that* is because of HIGHMEM. > > So it's all entirely silly and pointless on any sane architecture, I think. > >> We'll need a preemption point there for CONFIG_PREEMPT_VOLUNTARY >> as well, right? > > Ahh, yes. I should have looked at the code, and not just gone by my > "PREEMPT_NONE vs PREEMPT" thing that entirely forgot about how we > split that up. > >> Just one minor point -- seems to me that the choice of nontemporal or >> temporal might have to be based on a hint to clear_huge_page(). > > Quite possibly. But I'd prefer that as a separate "look, this > improves numbers by X%" thing from the whole "let's make the > clear_huge_page() interface at least sane". Makes sense to me. -- ankur