From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.60 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793718864; b=0zJKvFNxXO+SqGNRuJ8JZwTRtMG0OTURbpzRRzKsM+oW2pysBn5xAhYL+ADdsrU/CRAM 278IzZGUJQDjI+gX6ZT6LAaPz0+s1LW0fW/kLfR4BI3g26yuVsaGJtvD1bhiholDaUtGN KZpu4VxEeOaxm5KsHB1E9heYXb5iaE8uFQ1EI2j89i8ru+Qe3FudQ0OXYhTluwJDJ9roc rD1AGQ7gSpkyK1/Z6NPTffGWq8VA83kkqCqI00YG0BV9RZQOjZqV2ASTcqwG0M1Gke/yU iJ21YQeTlNV42yrdYcw/twKZre+AntjU2ii4yuDk3ybychyH349IdwO7Abj9/6FZjcA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793718864; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:To:Cc:Subject:Date:Message-ID: X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=14hcT6F4fj8zJj0gPfB9WiAi+uaybopFKajULVBMQnI=; b=OBq88fIoQos0ubhtNfanWeghNTx5Zi89A3FtbKyCeI5xKIbUoY5gdioxefpT0p3VhAr4 Vgw3mYVpaEvyTYKNEGbHEyVPK1UxCus67VxYYS1qeCqLUqtid5Wv8t85Oc2I9tUDaZsIu 2tW32bjNC0XD48EGV49Xjt8GhXvzDw3M1ZGlS7rGo+w9HiU/PKEae0NnbdaMY5CaqSpTS zlwZCxdgspI7ETTZJoiU+A5aa5w+MUPIVY3xSWrjpEDggOrQ8HhLNQJ1RljJN2uZxjjnL Ti7ziWbu3CYaGSCQa/v64yHvZXnySzcFnl78AkDkFn0wqtuD8yW9XMfxZI2jQrpi16g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=ts5HB9y2; arc=none smtp.remote-ip=91.218.175.60 Received: from mta0.migadu.com (out-60.mta0.migadu.com [91.218.175.60]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9DEC2606A79F for ; Tue, 3 Nov 2026 15:14:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 9DEC2606A79F Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=ts5HB9y2 X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=/n6q6+lIX9B5ZuliSLqd+JJa2B0QDGQRcHf36WsHI7Q=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793718861; v=1; x=1794323661; b=ts5HB9y28ZzWXoUo+d+m68JgTc6d40SOeizyYnSAdoBpXnsyKf1HioVJw2sd1J/ysygB1Kx/ e64gLcGfgRbQFzbr3FKFgzMKXjBuYVURrWLNzVd6xMUrDy71PsneXa7FBxNvenPg4GGPhTAsRVD 8G1VawouDX2sNWIeVN26sFcM= X-Envelope-To: linux-kernel@vger.kernel.org Received: by mta12.migadu.com with ESMTPS id 198054973b778b6a; Tue, 03 Nov 2026 15:14:20 +0000 X-Mizu-Trace-ID: 198054973b778b6a X-Migadu-Flow: FLOW_OUT From: Usama Arif To: Lance Yang Cc: Usama Arif , akpm@linux-foundation.org, david@kernel.org, chrisl@kernel.org, kasong@tencent.com, ljs@kernel.org, ziy@nvidia.com, linux-mm@kvack.org, ying.huang@linux.alibaba.com, baoquan.he@linux.dev, willy@infradead.org, youngjun.park@lge.com, hannes@cmpxchg.org, riel@surriel.com, shakeel.butt@linux.dev, alex@ghiti.fr, kas@kernel.org, baohua@kernel.org, dev.jain@arm.com, baolin.wang@linux.alibaba.com, nico.pache@linux.dev, liam@infradead.org, ryan.roberts@arm.com, vbabka@kernel.org, linux-kernel@vger.kernel.org, nphamcs@gmail.com, shikemeng@huaweicloud.com, yosry@kernel.org, qi.zheng@linux.dev, luizcap@redhat.com, kernel-team@meta.com Subject: Re: [PATCH v8 00/30] mm: PMD-level swap entries for anonymous THPs Date: Tue, 3 Nov 2026 07:14:15 -0800 Message-ID: <20261103151416.1720617-1-usama.arif@linux.dev> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261004030844.90483-1-lance.yang@linux.dev> References: X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Sun, 4 Oct 2026 11:08:44 +0800 Lance Yang wrote: > Hey Usama, > > Staring at the swap-entry bits across architectures, and RISC-V looks a > bit off in that regard ... > > With Svrsw60t59b and CONFIG_MEM_SOFT_DIRTY=y, setting swap soft-dirty also > sets _PAGE_EXEC. A migration PMD then looks present ... so the fault > handler skips the migration wait :( > > And yeah, this is a pre-existing bug. I've sent a separate fix for it. > Thanks for the fix! PMD swap entries also preserve soft-dirty, so the same encoding issue affects this series. The dependency note lists your separate fix for RISC-V with Svrsw60t59b and soft-dirty enabled. It applies cleanly and preserves the exclusive marker at bit 6. > https://lore.kernel.org/linux-mm/20261004030312.90163-1-lance.yang@linux.dev/ > > BTW, could we also add more checks to pmd_leaf_soft_dirty_tests() so we > catch this kind of issue early? Setting a swap flag shouldn't make a > non-present PMD present, IIUC. Done. The pgtable test now sets swap soft-dirty, checks that the flag is set, and checks that the PMD remains non-present. > > ---8<--- > diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c > index 863111c6d4eb..80686e2baaa1 100644 > --- a/mm/debug_vm_pgtable.c > +++ b/mm/debug_vm_pgtable.c > @@ -762,7 +762,9 @@ static void __init pmd_leaf_soft_dirty_tests(struct pgtable_debug_args *args) > WARN_ON(!pmd_is_huge(pmd)); > WARN_ON(!pmd_is_valid_softleaf(pmd)); > > - WARN_ON(!pmd_swp_soft_dirty(pmd_swp_mksoft_dirty(pmd))); > + pmd = pmd_swp_mksoft_dirty(pmd); > + WARN_ON(!pmd_swp_soft_dirty(pmd)); > + WARN_ON(pmd_present(pmd)); > WARN_ON(pmd_swp_soft_dirty(pmd_swp_clear_soft_dirty(pmd))); > } > #else /* !CONFIG_TRANSPARENT_HUGEPAGE */ > -- > > [...] > > Cheers, Lance >