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[172.10.233.147]) by smtp.gmail.com with ESMTPSA id 00721157ae682-84caabb9e88sm34055617b3.29.2026.08.24.07.30.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Aug 2026 07:30:08 -0700 (PDT) Date: Mon, 24 Aug 2026 07:30:04 -0700 (PDT) From: Hugh Dickins To: 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 , Jens Axboe , 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 , Vlastimil Babka , 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 Subject: [PATCH 16/25] mm/fbatch: remove lru_cache_disable(() from NUMA folio migration In-Reply-To: <14a16945-529b-8bc0-ab38-3ea97e54e223@google.com> Message-ID: References: <14a16945-529b-8bc0-ab38-3ea97e54e223@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Remove lru_cache_disable() from mbind(MOVE), migrate_pages and move_pages syscall handling. They do not now benefit from lru_add_drain_all() first; they gain little benefit from invalidating buffer head LRUs first, since 5.0 commit 80409c65e2c6 ("mm: migrate: make buffer_migrate_page_norefs() actually succeed"); and it's a shame that (even without CAP_SYS_NICE) they can prevent concurrent tasks from enjoying the use of those caches. Signed-off-by: Hugh Dickins --- mm/mempolicy.c | 7 ------- mm/migrate.c | 3 --- 2 files changed, 10 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 501e0b80d7da..44912d707d57 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1343,8 +1343,6 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from, long err = 0; nodemask_t tmp; - lru_cache_disable(); - /* * Find a 'source' bit set in 'tmp' whose corresponding 'dest' * bit in 'to' is not also set in 'tmp'. Clear the found 'source' @@ -1425,7 +1423,6 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from, break; } - lru_cache_enable(); if (err < 0) return err; return (nr_failed < INT_MAX) ? nr_failed : INT_MAX; @@ -1530,8 +1527,6 @@ static long do_mbind(unsigned long start, unsigned long len, if (!new) flags |= MPOL_MF_DISCONTIG_OK; - if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) - lru_cache_disable(); { NODEMASK_SCRATCH(scratch); if (scratch) { @@ -1626,8 +1621,6 @@ static long do_mbind(unsigned long start, unsigned long len, putback_movable_pages(&pagelist); mpol_out: mpol_put(new); - if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) - lru_cache_enable(); return err; } diff --git a/mm/migrate.c b/mm/migrate.c index 534908a0839a..bf9fe533a5fb 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2360,8 +2360,6 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, int start, i; int err = 0, err1; - lru_cache_disable(); - for (i = start = 0; i < nr_pages; i++) { const void __user *p; int node; @@ -2440,7 +2438,6 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, if (err >= 0) err = err1; out: - lru_cache_enable(); return err; } -- 2.51.0