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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776330314; bh=lBDsRUuMGhTc1NAeKI+5vxXQ9iIujjveKnsUNxxcylM=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=LcWeFcncx61U7p1+yKL5NpfL++JeYoYRjLhJiUyYhVpdqS/zABlrUxS8F8UKOhOh1 bHJX0oOpn7nd4740DYLgIUHUYYcNG8ZyLez5s4+MRvlYNV5hl5O0JROlQylzN2AxYk PD1krnaY/lRRi+sDigUuwlupLH+S+/3yNmkKwp1wAyHUVR/vRuA1bUXw3N99HTbmXr 31lDmAlfodk6RSapYYyo1EkAQ+lP0G0goSMI7p6gkX/Ohv4taHdEPZNtyZ0LmPTIB+ Jmem8q+5sYhXobZbFyUODmS8TBkMIafPmsevZwb6o9sfyUMlce4p+LIlzxFfeWG26N tUIe1LZNjp81w== Received: by mail-qv1-f51.google.com with SMTP id 6a1803df08f44-8a08fa355a1so106635866d6.0 for ; Thu, 16 Apr 2026 02:05:14 -0700 (PDT) X-Gm-Message-State: AOJu0YxAS7yZY2GAh+EM62yoQuWLXiGKXM+FZrJr4mIs8yunqb8wC7y3 PiEK42JF7+Otmjh7PWplDKf3ZXi7t4oMe0UhrDIgXPUZCC1rWxiKDYzT6ASIGEpS+TJW5pxhneC mOrkZqkqXo/TCULZHdxfHiZNuX5WhCIA= X-Received: by 2002:ad4:5ece:0:b0:8ae:66cf:423d with SMTP id 6a1803df08f44-8ae66cf4357mr127506276d6.18.1776330314058; Thu, 16 Apr 2026 02:05:14 -0700 (PDT) MIME-Version: 1.0 References: <20260413-mglru-reclaim-v5-0-8eaeacbddc44@tencent.com> <20260413-mglru-reclaim-v5-8-8eaeacbddc44@tencent.com> In-Reply-To: <20260413-mglru-reclaim-v5-8-8eaeacbddc44@tencent.com> From: Barry Song Date: Thu, 16 Apr 2026 17:05:02 +0800 X-Gmail-Original-Message-ID: X-Gm-Features: AQROBzASHcdgacejWAY7DLHYfWkOHcvbPhd6TD15rHsqXg1dPxd28jwuhtKK-dE Message-ID: Subject: Re: [PATCH v5 08/14] mm/mglru: remove redundant swap constrained check upon isolation To: kasong@tencent.com Cc: linux-mm@kvack.org, Andrew Morton , Axel Rasmussen , Yuanchu Xie , Wei Xu , Johannes Weiner , David Hildenbrand , Michal Hocko , Qi Zheng , Shakeel Butt , Lorenzo Stoakes , David Stevens , Chen Ridong , Leno Hou , Yafang Shao , Yu Zhao , Zicheng Wang , Kalesh Singh , Suren Baghdasaryan , Chris Li , Vernon Yang , linux-kernel@vger.kernel.org, Qi Zheng , Baolin Wang Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: D93DEA0002 X-Rspamd-Server: rspam12 X-Stat-Signature: c1cqake88ahmnbao6g7td9apohat4i41 X-Rspam-User: X-HE-Tag: 1776330315-995353 X-HE-Meta: U2FsdGVkX18xEgkZALydC/Pps3yl8iE054bo3QgNJzJyS9K317414fpcH2I9tqf2Oyw9lmvWQPPCWzjbSdfq09lGEMTxxcCioeZea70wFiAYm3gI+X0oMA5ewbqzrIHOvbTmoI+h/G9BpqfwcBCdriISIJNj+RoDMaL+nhAjl6ZA51/MRZXKOUB7IljoFbueUNB+cVN9HbsqIwgqpB3e335esTql53GDyNHOSqvsO8R73IqoQUasFZTbfdwtEE6/z82bf7VkZqKNNBctKJ0rgZRZXzzEZhVSqBCWpbp8BE70EVChWuiye3x3i7Y1IaLQ0cF9hj3UbGTtRodZ7VFXyV2hoXW6nI9IjVtolYiCmNq8pFDHrcooYXo2s7Jt/UxI1WGtTbo1s/rYxrFY43qxaiObWN9Tk7/lIClvAH+yVmRZ/bbXRUxx86AkxgRPNsRzgAw6nfamU/PdtoRivzZynf4Pzsmt/TYzNr/GCB/2rWheMfZ6BzKseqKBaBo+vU4uxLFLDxYNiI3WlND+E9rlXatUE8+qN6xrTQZNSLAttjhc4PfRGkifJV6W1xtjm8PV120WrLHh6ret5gDXyjaaqVNzotT2piANKKZE0vSnMBdq5UaaqNrNGYioRZH2h0Gu4Hk+XjtdUFOVEsM/uEvAJw8GcJ74qjbHNmY38lXD849dMudKdwbpmmhI4gKH1fRg9ICDRbyOkw7Zkpyy0MDon1YdUgZjcD9yogftXyLphMqQz67zZ4NElIGpXSnTKLxeAFm5P+ub5viEAPW6WphVXKt16WDJPo+TdECEuL45yDXNSyt+zpvejGuQ+qdZKMewCx6BaoOYrddAmkuvDLf33VfKjW8DaIK5xK3iCExsjsWApLHPMhQImc5w3P0HJZKpi5a9XK70I3G8jfwYupqxS5hTBbmCKnE/8cckI4YIkpEYntdUWUKoso+LpZvm0mmJOUWA8ilKj2uU1nTRuHl vr/rXe8l 6ZXImclb8j60+QINXvaPYdj5xNK1lZgWoWn/ove5FTETtzYyrMQc/pjg7lXdNhfUxGMfQ8hcBZ60GdahM0rLiqPxf2JlWcmYn7byipHiW4c7Uy9cTict8Trxcf2HmeoRBHc9EouE3xdaJ5SQRC/HwUalMwsZRVmL9izoe0KcFogYmsNcvu53ynVFfeynZxmcgTQDspXvRsurRjmy7tAx5xl/NJLVWoTn94bY6eQISEbguLKc2k6SQcKmjGw+zjWAtsH0qSixTxz2WXKnT8dN8n/HLTvIxyNdb7i5WKsYu6KkpHHSdA8VcrEWGlkj77ODifn6rHmMZyCw0Ji8laqat60y0oe19PKF75jzYWmuYUQISTjfRGIJ2QXMLLQpdEhVthpvJIwSsP0TOBWNgf9UFM0KVv1ysZLqtadEdrOHX36Dz9Dc= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Apr 13, 2026 at 12:48=E2=80=AFAM Kairui Song via B4 Relay wrote: > > From: Kairui Song > > Remove the swap-constrained early reject check upon isolation. This > check is a micro optimization when swap IO is not allowed, so folios are > rejected early. But it is redundant and overly broad since > shrink_folio_list() already handles all these cases with proper > granularity. > > Notably, this check wrongly rejected lazyfree folios, and it doesn't It seems the original code somehow missed folio_test_swapbacked(). > cover all rejection cases. shrink_folio_list() uses may_enter_fs(), > which distinguishes non-SWP_FS_OPS devices from filesystem-backed swap > and does all the checks after folio is locked, so flags like swap cache > are stable. > > This check also covers dirty file folios, which are not a problem now > since sort_folio() already bumps dirty file folios to the next > generation, but causes trouble for unifying dirty folio writeback > handling. > > And there should be no performance impact from removing it. We may have > lost a micro optimization, but unblocked lazyfree reclaim for NOIO > contexts, which is not a common case in the first place. > > Reviewed-by: Axel Rasmussen > Signed-off-by: Kairui Song Reviewed-by: Barry Song