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b=JiZa1FAGRjiBxr4eCE7etd8xF5Ox2fvunf4Jh+pFg1WAlP4CubwSmpW8U6vTnZbqI YPq9gfVGk9OeA9lPeUUItoILDjtrvzuNLB1QRZzdMNroVNsqitDi63hRXYHDWz8faX ryQ4NCpeoWxNaIWCwerL0PlpSURsC79JZceJ11MmTMhmAQPP9fUSqHbOMpekl2pkdx jgPUXw+/QOFPPU4n9pXbY5TmblnOwnS2K0Y1UVizacnB1rHu1w//n5XlgfEoru/2O7 pCEWvLm7W9BGee4uNRUQoDTIiJNIonPu9E1BUPZULWOxY3pMWs2zt/FjbDlFGfVudH /BwFmrRFqP37A== Message-ID: <25144cf6-a5ae-4e1f-b77b-768e2636825f@kernel.org> Date: Tue, 8 Sep 2026 18:21:43 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 02/25] mm/fbatch: allow folios_put_refs() to skip xa_is_value() entries Content-Language: en-US To: Hugh Dickins , Andrew Morton Cc: Ackerley Tng , Alexander Viro , Baolin Wang , Barry Song , Binbin Wu , Christian Brauner , Christoph Hellwig , Christoph Lameter , Claudio Imbrenda , David Hildenbrand , JP Kobryn , Jan Kara , Johannes Weiner , Kairui Song , Kiryl Shutsemau , Lance Yang , Leonardo Bras , Lorenzo Stoakes , Marcelo Tosatti , Matthew Wilcox , Mel Gorman , Miaohe Lin , Michal Hocko , Minchan Kim , Muchun Song , Oscar Salvador , Peter Zijlstra , Qi Zheng , Rik van Riel , Sebastian Andrzej Siewior , Shakeel Butt , Suren Baghdasaryan , Yang Shi , Yu Zhao , Zach O'Keefe , Zi Yan , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <14a16945-529b-8bc0-ab38-3ea97e54e223@google.com> <44c7773e-5806-d24a-83c9-f39b3a134138@google.com> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Stat-Signature: miri7nmqwqzxbnenq93cx4hig39ds3xx X-Rspamd-Queue-Id: ADFDDA000D X-Rspamd-Server: rspam07 X-HE-Tag: 1788884513-667264 X-HE-Meta: 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 7pAZl1ZZ /+qwua7oE2kct1tp97u/v0nfza3q+KyOsUTqYeuXPkJ2L5cniVNjD27h7IvylQK38oe98UWsDoS8uYoVsD/J+ujeV6VMUsy9ofkS/grxsMw5xkAAGKdRtgCbtm9sRIkN70PT31+nkBW/PcteyCDzvC1eknjIJ0qIcIcctR1Ce7YItm9NbA4iU8huHWpbV9ltMb8jHaChvz225PokhO3klKupQHN69HebEYuz3U040z1HxHXKWLmYmriox2Tvi04MnyHjwx6UOp9dzyatnfBlwmCcZtg48Pbp/blhDNjkwynpXItLBaKDx6xUUM7iOo36EdLtYyjol/2b9x1GrjehkwATjxQRfiwbGuBX+LiYobgLfrfgqy8K/2by7N3Uqw280MiTIEtKJF1jLq5JFr5QI+kK4U4fSRSYPdre8dMpNe0g3p6s= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 8/24/26 15:55, Hugh Dickins wrote: > Let folios_put_refs() (hence folio_batch_release()) skip xa_is_value() > entries, and therefore remove unneeded folio_batch_remove_exceptionals(). > > It made some sense when introduced in 3.1 for shmem swap entries only, > but workingset shadows popularized exceptional entries in 3.15, and it's > silly for so many sites to be squashing exceptionals out of the fbatch, > merely to suit an inadequacy in folios_put_refs(). > > But remove exceptionals on leaving truncate_folio_batch_exceptionals(), > one of whose callers then passes the fbatch on to others less tolerant. > > No longer essential to this series, since 7.2 commit 9669b87065a6 > ("mm/lruvec: preemptively free dead folios during lru_add drain") > allowed folios_put_refs() to skip NULLs; but still an improvement. > > Signed-off-by: Hugh Dickins Like David, I don't understand what exactly truncate_folio_batch_exceptionals() does. But this patch seems correct to me, so: Reviewed-by: Vlastimil Babka (SUSE)