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charset="UTF-8" ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1662698424; a=rsa-sha256; cv=none; b=dne82h/aRcaXvTsIIdsOMkZYCs1YhmJJAMPHNHKJo6UOXAVXkj/ig6ojExpVXcNls+mMcU Zu68PNZMhxcXWpr2eg08dzkuAwG8H8FV3RPg36rx/GJkBoHLOx4gGX17sFr7qfp1qZ+oEZ NyLQabQChWWN7kChHHpYBpsznqk/yd4= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=meNsPfiL; spf=pass (imf13.hostedemail.com: domain of 21cnbao@gmail.com designates 209.85.218.54 as permitted sender) smtp.mailfrom=21cnbao@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1662698424; 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-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=NOESYgoK2wMPdnD2YfaTrguO/djOwdOuUJuGX9ov7n8=; b=hMmr4YDWkZy4pcftXciNrtrA1LI4ugkVq05Q/jKJBoVYnOubYJ34Vqo+5DT8sbbLnq14ut QMwfqkOQiiHMXpUDWdNRx60BbspHCvOTvycD4gUGFcjoXy1ttaZ076r5mWrQsnOf3QBHsT MSCnLHaS6Z3j6aV/gqB66+KM9mu/9mY= X-Stat-Signature: wakoihza7jxebaoodzqn37su63q9mhu6 X-Rspam-User: X-Rspamd-Queue-Id: 92BD32007E X-Rspamd-Server: rspam07 Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=meNsPfiL; spf=pass (imf13.hostedemail.com: domain of 21cnbao@gmail.com designates 209.85.218.54 as permitted sender) smtp.mailfrom=21cnbao@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-HE-Tag: 1662698424-449425 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 Fri, Sep 9, 2022 at 4:26 PM Anshuman Khandual wrote: > > > > On 8/22/22 13:51, Yicong Yang wrote: > > From: Barry Song > > > > This reverts commit 6bfef171d0d74cb050112e0e49feb20bfddf7f42. > > > > I was wrong. Though ARM64 has hardware TLB flush, but it is not free > > and it is still expensive. > > We still have a good chance to enable batched and deferred TLB flush > > on ARM64 for memory reclamation. A possible way is that we only queue > > tlbi instructions in hardware's queue. When we have to broadcast TLB, > > we broadcast it by dsb. We just need to get adapted the existing > > BATCHED_UNMAP_TLB_FLUSH. > > > > Tested-by: Xin Hao > > Signed-off-by: Barry Song > > Signed-off-by: Yicong Yang > > --- > > Documentation/features/arch-support.txt | 1 - > > Documentation/features/vm/TLB/arch-support.txt | 2 +- > > 2 files changed, 1 insertion(+), 2 deletions(-) > > > > diff --git a/Documentation/features/arch-support.txt b/Documentation/features/arch-support.txt > > index 118ae031840b..d22a1095e661 100644 > > --- a/Documentation/features/arch-support.txt > > +++ b/Documentation/features/arch-support.txt > > @@ -8,5 +8,4 @@ The meaning of entries in the tables is: > > | ok | # feature supported by the architecture > > |TODO| # feature not yet supported by the architecture > > | .. | # feature cannot be supported by the hardware > > - | N/A| # feature doesn't apply to the architecture > > > > diff --git a/Documentation/features/vm/TLB/arch-support.txt b/Documentation/features/vm/TLB/arch-support.txt > > index 039e4e91ada3..1c009312b9c1 100644 > > --- a/Documentation/features/vm/TLB/arch-support.txt > > +++ b/Documentation/features/vm/TLB/arch-support.txt > > @@ -9,7 +9,7 @@ > > | alpha: | TODO | > > | arc: | TODO | > > | arm: | TODO | > > - | arm64: | N/A | > > + | arm64: | TODO | > > | csky: | TODO | > > | hexagon: | TODO | > > | ia64: | TODO | > > I believe this patch is not needed, which explicitly reverts an > older commit. Instead when ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH > framework gets enabled on arm64, the same patch could just drop > 'NA' as possible values for arch support for a give feature in > file Documentation/features/arch-support.txt. Sure. it is certainly ok to fix this in arm64: support batched/deferred tlb shootdown during page reclamation By a separate patch, I was trying to highlight that my previous patch was wrong. but, yes. it is not fundamentally necessary. Thanks Barry