From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-120.mta0.migadu.com [91.218.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3FC04471D0B for ; Mon, 14 Sep 2026 12:31:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.120 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789389107; cv=none; b=ks7l1eYGOqTjl5kiYP8VpbhpfNMYjWiLbsGxB4vJA3nucrK0TbI3VEahzeqv5dHAldT1NaBTyBsH0a9wVTF9BVZUFwuLQRsGTVpAlrNLIyFCn5Q9Z7xbWw+SjyPjqPZY3Y+s1BAm0k/hLB4JrPuTzhyKdOwqaxfo3YTLWLNuz6s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789389107; c=relaxed/simple; bh=ENO5TWLGQORFi4I6GbjA3CLf4xd6bsmKP3WV+1rfFXs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qUv8zbZDMhsXk80VQrsckGCjPyC0XdDC4dkvZu8bWmeiuTmMks7wdwo4XY9c7TyUa1Zxne8XXdrqjeXiO3GMfzBPYmM8+MoHipZ4Le78Cjp15yFrUigJzEJ4bKLIJYEh0SEebPJL7AEm+ePm88gXxTeHIlq4tXryVcneK3ov3bE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=h3QkhiwX; arc=none smtp.client-ip=91.218.175.120 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) header.d=linux.dev header.i=@linux.dev header.b="h3QkhiwX" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=ENO5TWLGQORFi4I6GbjA3CLf4xd6bsmKP3WV+1rfFXs=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1789389099; v=1; x=1789993899; b=h3QkhiwXYcTZIuHPfBY/OApK3oAnJPSf4MiaDXPLEk9gGD9P6GFCYLAoIXZBL/jB3dUBs7VG FtFp5iyFFU+RiwZ8UliwaICS2TK2uZ70h4jBqnHRXIdK82c5JEM0SWi/byRUAi8R5q1edN5041a nF94ai5PgXcbzkDYzG9wWh48= X-Envelope-To: linux-kernel@vger.kernel.org Received: by mta11.migadu.com with ESMTPS id da37515ffb07b15a; Mon, 14 Sep 2026 12:31:39 +0000 X-Mizu-Trace-ID: da37515ffb07b15a X-Migadu-Flow: FLOW_OUT From: Usama Arif To: Andrew Morton , david@kernel.org, chrisl@kernel.org, kasong@tencent.com, ljs@kernel.org, ziy@nvidia.com, linux-mm@kvack.org Cc: ying.huang@linux.alibaba.com, Baoquan He , 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 , Liam R. Howlett , ryan.roberts@arm.com, Vlastimil Babka , lance.yang@linux.dev, 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, Usama Arif Subject: [RESEND v7 15/29] fs/proc: account PMD swap entries in smaps Date: Mon, 14 Sep 2026 05:28:05 -0700 Message-ID: <20260914122950.3283997-16-usama.arif@linux.dev> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260914122950.3283997-1-usama.arif@linux.dev> References: <20260914122950.3283997-1-usama.arif@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit smaps_pmd_entry() derives a page from a non-present PMD and gives up if it cannot. A PMD swap entry carries no PFN, so a swapped-out THP is accounted nowhere: its bytes show up in neither Swap nor SwapPss, and VmSwap silently loses them. The slots of a PMD swap entry can have different swap reference counts, so SwapPss has to be computed one slot at a time rather than divided once. Factor that loop out of smaps_pte_entry() and call it from both levels, then return early: a swapped-out THP is not resident and must not be added to AnonHugePages or Rss. pagemap needs no equivalent change - it already emits PM_SWAP and type | offset+idx for a PFN-less softleaf entry - but its thp_migration_supported() gate answers a different question than the decode requires, so use pmd_is_valid_softleaf() there instead. Signed-off-by: Usama Arif --- fs/proc/task_mmu.c | 42 ++++++++++++++++++++++++++++-------------- 1 file changed, 28 insertions(+), 14 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 24425e2308951..aa3f4d54a8580 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -957,6 +957,27 @@ static void smaps_pte_hole_lookup(unsigned long addr, struct mm_walk *walk) #endif } +static void smaps_account_swap(struct mem_size_stats *mss, + softleaf_t entry, unsigned long size) +{ + unsigned long nr_pages = size >> PAGE_SHIFT; + + mss->swap += size; + do { + int mapcount = swp_swapcount(entry); + + if (mapcount >= 2) { + u64 pss_delta = (u64)PAGE_SIZE << PSS_SHIFT; + + do_div(pss_delta, mapcount); + mss->swap_pss += pss_delta; + } else { + mss->swap_pss += (u64)PAGE_SIZE << PSS_SHIFT; + } + entry.val++; + } while (--nr_pages); +} + static void smaps_pte_entry(pte_t *pte, unsigned long addr, struct mm_walk *walk) { @@ -978,18 +999,7 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr, const softleaf_t entry = softleaf_from_pte(ptent); if (softleaf_is_swap(entry)) { - int mapcount; - - mss->swap += PAGE_SIZE; - mapcount = swp_swapcount(entry); - if (mapcount >= 2) { - u64 pss_delta = (u64)PAGE_SIZE << PSS_SHIFT; - - do_div(pss_delta, mapcount); - mss->swap_pss += pss_delta; - } else { - mss->swap_pss += (u64)PAGE_SIZE << PSS_SHIFT; - } + smaps_account_swap(mss, entry, PAGE_SIZE); } else if (softleaf_has_pfn(entry)) { if (softleaf_is_device_private(entry)) present = true; @@ -1019,9 +1029,13 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr, if (pmd_present(*pmd)) { page = vm_normal_page_pmd(vma, addr, *pmd); present = true; - } else if (unlikely(thp_migration_supported())) { + } else { const softleaf_t entry = softleaf_from_pmd(*pmd); + if (softleaf_is_swap(entry)) { + smaps_account_swap(mss, entry, HPAGE_PMD_SIZE); + return; + } if (softleaf_has_pfn(entry)) page = softleaf_to_page(entry); } @@ -2000,7 +2014,7 @@ static int pagemap_pmd_range_thp(pmd_t *pmdp, unsigned long addr, flags |= PM_UFFD_WP; if (pm->show_pfn) frame = pmd_pfn(pmd) + idx; - } else if (thp_migration_supported()) { + } else if (pmd_is_valid_softleaf(pmd)) { const softleaf_t entry = softleaf_from_pmd(pmd); unsigned long offset; -- 2.53.0-Meta