From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2C0BDCA1016 for ; Mon, 8 Sep 2025 06:22:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3C1018E0006; Mon, 8 Sep 2025 02:22:12 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 34B598E0001; Mon, 8 Sep 2025 02:22:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 261128E0006; Mon, 8 Sep 2025 02:22:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 0E48C8E0001 for ; Mon, 8 Sep 2025 02:22:12 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id A56245C30F for ; Mon, 8 Sep 2025 06:22:11 +0000 (UTC) X-FDA: 83865088062.30.635325F Received: from out-177.mta0.migadu.com (out-177.mta0.migadu.com [91.218.175.177]) by imf27.hostedemail.com (Postfix) with ESMTP id AE5D340004 for ; Mon, 8 Sep 2025 06:22:09 +0000 (UTC) Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=MBdxnENF; spf=pass (imf27.hostedemail.com: domain of liu.yun@linux.dev designates 91.218.175.177 as permitted sender) smtp.mailfrom=liu.yun@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1757312530; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=NBmb7oUqdoCzhCm2AnJKPGujkmoHds2eGlcnyfX2ybM=; b=ymG2pTX5kMe8xrWK4+Sc61ZV6owPJ5x8QoOOLCveF4QEgZXC2hZa4Aj3TakeVwuNa4Ix3G oYc6ZbfqmImeJPzF+WvtHD0Gp1UqVgvzzOmFthVTv5Ou/3AEWDEmqdCd2OVyWw+af43orE Ax10pYT9tX+GkOebHQ+TOVYAifOph4s= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1757312530; a=rsa-sha256; cv=none; b=GQpVyRBh/E7RbzDAZX4bYrO12+pSJWqJrZ5alcLRT2BJyMNRzMgC5Vew1kNbfDNqMh3IkB rEsOy2a7Elg7kJAt+s5BmMWsznLx5ykFuuhIOvtp+34oqk5rIQ3MeXkHOw0U0QXiy4TmqF sxrDghFk8pqm3ov8QQHtSRS5+HVDyi4= ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=MBdxnENF; spf=pass (imf27.hostedemail.com: domain of liu.yun@linux.dev designates 91.218.175.177 as permitted sender) smtp.mailfrom=liu.yun@linux.dev; dmarc=pass (policy=none) header.from=linux.dev MIME-Version: 1.0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1757312526; h=from:from: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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NBmb7oUqdoCzhCm2AnJKPGujkmoHds2eGlcnyfX2ybM=; b=MBdxnENF56/rocq2cL6js/NQd6A7dIVoaIMbB+jg891jIfODYfQjwTKbLuJ+5pzuuDEZr3 nSTiOH0RaQSTRhLiVjm6f05Eu9VgCujxGdd/HHs/69cjBlMM+TmWJjT5uBk9MItk4PQsv8 9we+U6N2RCoHXLcgdgdLTk3Eo4WLh+I= Date: Mon, 08 Sep 2025 06:22:02 +0000 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: "Jackie Liu" Message-ID: <53349cec552be79b9da6776ff778ea45fc3c4bf7@linux.dev> TLS-Required: No Subject: Re: [PATCH] mm/shmem: remove redundant entry_order variable in shmem_split_large_entry() To: "Baolin Wang" , linux-mm@kvack.org, akpm@linux-foundation.org Cc: hughd@google.com, liuyun01@kylinos.cn In-Reply-To: <888448f1-518b-49f2-9c91-1f4434777720@linux.alibaba.com> References: <20250908023915.28907-1-liu.yun@linux.dev> <20250908023915.28907-2-liu.yun@linux.dev> <888448f1-518b-49f2-9c91-1f4434777720@linux.alibaba.com> X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: AE5D340004 X-Stat-Signature: jpj8eqarth1f5m33yb6ew8ub886emug9 X-HE-Tag: 1757312529-871457 X-HE-Meta: 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 FLVnM4Jt gfBxf0TtLZUolehO+HAWYsODA9llJE5RPeszrpA9ViPE+e6mvTE2MLv7kP2QRuBnHZXc+0hkTPu9dd6fGILZdCVBi2iK1EYwaf5v5PzfaFSrMTRsw5R9guhHXf2KMW8TbBqD+3c14zr2CqlJaVY5U9gvq/kDiucZcfC2FWlvtNDHX8Aj1E5ssBDVJ7yk4k0PuEqDBHyYsDH8P62+4TJ0CVo9z0hO5CWZEgFKLzRIcZKX8eLo= 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: List-Subscribe: List-Unsubscribe: Hi Baolin. 2025=E5=B9=B49=E6=9C=888=E6=97=A5 14:05, "Baolin Wang" =E5=86=99=E5=88=B0: >=20 >=20On 2025/9/8 10:39, Jackie Liu wrote: >=20 >=20>=20 >=20> From: Jackie Liu > > Commit d53c78fffe7a ("mm/shmem: use xas_try_split() in shmem_split_l= arge_entry()") > > reworked shmem_split_large_entry() to use xas_try_split() and simpli= fied > > the splitting logic. After that change, the local variable `entry_or= der` > > became redundant since its value was always immediately copied to `c= ur_order`. > > Remove `entry_order` and use `cur_order` directly to simplify the co= de. > >=20 >=20The commit message is a bit misleading. It does not introduce a redun= dant variable by commit d53c78fffe7a. Instead, it's because after commit = 93c0476e7057 ("mm/shmem, swap: rework swap entry and index calculation fo= r large swapin"), the 'entry_order' will never be returned. >=20 Aha,=20Thanks, you=E2=80=99re right. This is indeed the correct commit. W= hen I applied this series of patches locally, I accidentally used an earlier prerequisite patch. I made a mistake when = copying it.=20 Thanks=20again=E2=80=94I=E2=80=99ll update the comment and resend version= 2.=20 --=20 Jackie Liu > >=20 >=20> No functional change intended. > > Signed-off-by: Jackie Liu > > --- > >=20 >=20With the commit message updated: > Reviewed-by: Baolin Wang >=20 >=20>=20 >=20> mm/shmem.c | 11 ++++------- > > 1 file changed, 4 insertions(+), 7 deletions(-) > > diff --git a/mm/shmem.c b/mm/shmem.c > > index e2c76a30802b..53d28ea6e52b 100644 > > --- a/mm/shmem.c > > +++ b/mm/shmem.c > > @@ -2235,7 +2235,7 @@ static int shmem_split_large_entry(struct inod= e *inode, pgoff_t index, > > { > > struct address_space *mapping =3D inode->i_mapping; > > XA_STATE_ORDER(xas, &mapping->i_pages, index, 0); > > - int split_order =3D 0, entry_order; > > + int split_order =3D 0; > > int i; > > > /* Convert user data gfp flags to xarray node gfp flags */ > > @@ -2253,15 +2253,12 @@ static int shmem_split_large_entry(struct in= ode *inode, pgoff_t index, > > goto unlock; > > } > > > - entry_order =3D xas_get_order(&xas); > > - > > - if (!entry_order) > > + cur_order =3D xas_get_order(&xas); > > + if (!cur_order) > > goto unlock; > > > /* Try to split large swap entry in pagecache */ > > - cur_order =3D entry_order; > > - swap_index =3D round_down(index, 1 << entry_order); > > - > > + swap_index =3D round_down(index, 1 << cur_order); > > split_order =3D xas_try_split_min_order(cur_order); > > > while (cur_order > 0) { > > >