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[188.141.5.72]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4887e83e906sm89863085e9.8.2026.04.01.00.47.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Apr 2026 00:47:56 -0700 (PDT) From: David Carlier To: Barry Song <21cnbao@gmail.com>, Kairui Song , David Hildenbrand , Chris Li , Andrew Morton , Kemeng Shi , Nhat Pham , Baoquan He , Youngjun Park , NeilBrown Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, David Carlier Subject: [PATCH v3] mm/page_io: use sio->len for PSWPIN accounting in sio_read_complete() Date: Wed, 1 Apr 2026 08:47:53 +0100 Message-ID: <20260401074753.238053-1-devnexen@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260330071229.14614-1-devnexen@gmail.com> References: <20260330071229.14614-1-devnexen@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" sio_read_complete() uses sio->pages to account global PSWPIN vm events, but sio->pages tracks the number of bvec entries (folios), not base pages. While large folios cannot currently reach this path (SWP_FS_OPS and SWP_SYNCHRONOUS_IO are mutually exclusive, and mTHP swap-in allocation is gated on SWP_SYNCHRONOUS_IO), the accounting is semantically inconsistent with the per-memcg path which correctly uses folio_nr_pages(). Use sio->len >> PAGE_SHIFT instead, which gives the correct base page count since sio->len is accumulated via folio_size(folio). Signed-off-by: David Carlier Acked-by: David Hildenbrand (Arm) --- mm/page_io.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page_io.c b/mm/page_io.c index 63b262f4c5a9..1389cd57ca88 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -497,7 +497,7 @@ static void sio_read_complete(struct kiocb *iocb, long = ret) folio_mark_uptodate(folio); folio_unlock(folio); } - count_vm_events(PSWPIN, sio->pages); + count_vm_events(PSWPIN, sio->len >> PAGE_SHIFT); } else { for (p =3D 0; p < sio->pages; p++) { struct folio *folio =3D page_folio(sio->bvec[p].bv_page); --=20 2.53.0