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Shutemov" , Sasha Levin , "Aneesh Kumar K . V" , Vlastimil Babka , Jerome Marchand , Andrea Arcangeli , Hugh Dickins , Jason Gunthorpe , John Hubbard , Peter Xu , Yang Shi Subject: [PATCH v1] mm/gup: adjust stale comment for RCU GUP-fast Date: Thu, 1 Sep 2022 09:21:19 +0200 Message-Id: <20220901072119.37588-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1662016888; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:references:dkim-signature; bh=NlolkOVzROxrmysLyLOweRyR0NiCeVgfH2ZsqTw7uYI=; b=uVXsoSFkY6Wfm3VLiKHwSriRuILpEkICbknLwLz2PJ+KE3fM5RBZ0Bc4ePQqg/4z90GDuN F1x2iuK8lS8y8ez44ncEuozYAOAEG5eLcmiOJfEspGDFq3HuS4T5xyFNI/E97iYkgI+w6E uSk8BDitDHbf8koCVyplO/12Wn51dIM= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Dibscjz1; spf=pass (imf14.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1662016888; a=rsa-sha256; cv=none; b=IaybKBsv2iebTBcuXVY8oQjK7heDt6N4WQ6KscRSkwvcP7LXzWgyIPnZlufgI/Uc5m+Thr ZgpOUnwktF3n3HR32QyylD0tjlVnUT85jSEHWuaHAZrO0ZassASB2a7CJ3qKSnrU2bq4ZD YBAxjO24miANm/0Itd62UZ4fF5x5CrI= X-Rspamd-Queue-Id: B6FC510002B Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Dibscjz1; spf=pass (imf14.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspam-User: X-Rspamd-Server: rspam10 X-Stat-Signature: g7xmcgpsp6yi6ycdb4i8nestthiqjrwo X-HE-Tag: 1662016888-188751 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: commit 4b471e8898c3 ("mm, thp: remove infrastructure for handling splitting PMDs") didn't remove all details about the THP split requirements for RCU GUP-fast. IPI broeadcasts on THP split are no longer required. Cc: Kirill A. Shutemov Cc: Sasha Levin Cc: Aneesh Kumar K.V Cc: Vlastimil Babka Cc: Jerome Marchand Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: John Hubbard Cc: Peter Xu Cc: Yang Shi Signed-off-by: David Hildenbrand Acked-by: Kirill A. Shutemov Reviewed-by: Jason Gunthorpe --- mm/gup.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 5abdaf487460..cfe71f422787 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2309,9 +2309,8 @@ EXPORT_SYMBOL(get_user_pages_unlocked); * * Another way to achieve this is to batch up page table containing pages * belonging to more than one mm_user, then rcu_sched a callback to free those - * pages. Disabling interrupts will allow the fast_gup walker to both block - * the rcu_sched callback, and an IPI that we broadcast for splitting THPs - * (which is a relatively rare event). The code below adopts this strategy. + * pages. Disabling interrupts will allow the fast_gup walker to block the + * rcu_sched callback. * * Before activating this code, please be aware that the following assumptions * are currently made: