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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6ABF6D2ECEF for ; Mon, 19 Jan 2026 23:02:31 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4dw5ZV1Z5yz30MY; Tue, 20 Jan 2026 10:02:26 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip="2600:3c0a:e001:78e:0:1991:8:25" ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1768863746; cv=none; b=ae2W9QCmRB4vJCrSF4UR9/awF0jiYlhk3IDvCf1n9kxlF2TmAK52Ad5Xmu4gilltugqTyVpbvvmEdC6OGSAcNB5GHIaU8ngKepyZJqg3TyOksactRgtu1MvHDnrNq0DoOvwfqs6/8x3k1RrMSJBMlpBcJ5Gkqphhi3pIJC2SAsSVeCqmhsqsmT+64938QCbhiz8xFDt/TIL/VwXpUDVT7l4LDpqmeBDkNcngL0L74SCGHkmx+33TZySIfnWOAOQIO/PQ62MDwIQBUNQ+UPgyqgsZtuhaD9uCuYr54EHy0/7pkcv8Ml3QMkMn3Y5dRF9HIcQSPg5ZFsMhSLwmzmEzNQ== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1768863746; c=relaxed/relaxed; bh=ttxPGtwt7jmM6c9nkDVBUEHXnIKNk4+FY3J8rzp2QMA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kSDPMJVlxcLa8RqysDU6Xrsgc2NYRmAzt/5oKD3dQnYfbk/JA6QTWfesjWgaXepdlgWiz/uN3F5Vp2CEPL3fPL2clgCNTxO4zm71+G+H2YCZUcFY8ZQpWDpouDPgJJZCiWPUUV5GhhH+q/xvZ9lGFdA8Swiw6XrE9OwJJ3h350TGg2g5tIuJUHcMUOFBQUfDyHFBj2LNIX1ZbhzlqgTJeacmcEVSY69DfIHo4OjLwC93hSdu1wy2qj9bYCl3Q9klndZyRHUruDaRvn7CcSvrZgOnDcwW14j4Irbl8bXGIlhiIf0IsPuybSES++hfYNLD1pTOkJPcgJcY6IUcYuPc4w== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=kernel.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=Cwpscc+r; dkim-atps=neutral; spf=pass (client-ip=2600:3c0a:e001:78e:0:1991:8:25; helo=sea.source.kernel.org; envelope-from=david@kernel.org; receiver=lists.ozlabs.org) smtp.mailfrom=kernel.org Authentication-Results: lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=kernel.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=Cwpscc+r; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=2600:3c0a:e001:78e:0:1991:8:25; helo=sea.source.kernel.org; envelope-from=david@kernel.org; receiver=lists.ozlabs.org) Received: from sea.source.kernel.org (sea.source.kernel.org [IPv6:2600:3c0a:e001:78e:0:1991:8:25]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4dw5ZT3X3vz2xpk for ; Tue, 20 Jan 2026 10:02:25 +1100 (AEDT) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id D974841A7B; Mon, 19 Jan 2026 23:02:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6E383C19424; Mon, 19 Jan 2026 23:02:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768863743; bh=SnhMKeXWJjdrWLtSbqKw7V4EMXVK/pgfK7VZwhJNF9w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Cwpscc+r+ZQnX9sK8UbIxMV80FOtiD0YmfSvImeyZ1PRPQH2lLEE20JaD3ObyynTS EGuheGjlkJBQOTWpsnYX+6heM102tLpDu6hT5riS/StPirtxFNFhQIt+gXzAzu7kUT Uzc4AuZlWiPVtXJnQFd63BCCJMA5kq3Amhls8qWKE7JNdROfRWhZztXHKUFcrYZNRw cVB+zSGrii6PulRMvxLEhh/ZRNUvVNnIvhFuWUFz+Uvo0liKLJgMoJUzmbMyXFccU9 /FyQCbCpzZq84lBXHcsEEz5XJxyaDrhzSquDZ/IjDQFhLnqPjvyS+ROF1QKGZ/ITAv Bphv7kbjcZ1ew== From: "David Hildenbrand (Red Hat)" To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, Broadcom internal kernel review list , linux-doc@vger.kernel.org, virtualization@lists.linux.dev, "David Hildenbrand (Red Hat)" , Andrew Morton , Oscar Salvador , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Arnd Bergmann , Greg Kroah-Hartman , Jerrin Shaji George , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Zi Yan Subject: [PATCH v3 06/24] mm/balloon_compaction: centralize adjust_managed_page_count() handling Date: Tue, 20 Jan 2026 00:01:14 +0100 Message-ID: <20260119230133.3551867-7-david@kernel.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260119230133.3551867-1-david@kernel.org> References: <20260119230133.3551867-1-david@kernel.org> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Let's centralize it, by allowing for the driver to enable this handling through a new flag (bool for now) in the balloon device info. Note that we now adjust the counter when adding/removing a page into the balloon list: when removing a page to deflate it, it will now happen before the driver communicated with hypervisor, not afterwards. This shouldn't make a difference in practice. Acked-by: Liam R. Howlett Acked-by: Michael S. Tsirkin Signed-off-by: David Hildenbrand (Red Hat) --- arch/powerpc/platforms/pseries/cmm.c | 13 +------------ drivers/virtio/virtio_balloon.c | 19 ++----------------- include/linux/balloon_compaction.h | 2 ++ mm/balloon_compaction.c | 17 +++++++++++++++++ 4 files changed, 22 insertions(+), 29 deletions(-) diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c index 15f873f733a41..7fd8b3d7e7637 100644 --- a/arch/powerpc/platforms/pseries/cmm.c +++ b/arch/powerpc/platforms/pseries/cmm.c @@ -165,7 +165,6 @@ static long cmm_alloc_pages(long nr) balloon_page_enqueue(&b_dev_info, page); atomic_long_inc(&loaned_pages); - adjust_managed_page_count(page, -1); nr--; } @@ -190,7 +189,6 @@ static long cmm_free_pages(long nr) if (!page) break; plpar_page_set_active(page); - adjust_managed_page_count(page, 1); __free_page(page); atomic_long_dec(&loaned_pages); nr--; @@ -515,16 +513,6 @@ static int cmm_migratepage(struct balloon_dev_info *b_dev_info, return -EBUSY; } - /* - * When we migrate a page to a different zone, we have to fixup the - * count of both involved zones as we adjusted the managed page count - * when inflating. - */ - if (page_zone(page) != page_zone(newpage)) { - adjust_managed_page_count(page, 1); - adjust_managed_page_count(newpage, -1); - } - /* * activate/"deflate" the old page. We ignore any errors just like the * other callers. @@ -551,6 +539,7 @@ static int cmm_init(void) return -EOPNOTSUPP; balloon_devinfo_init(&b_dev_info); + b_dev_info.adjust_managed_page_count = true; if (IS_ENABLED(CONFIG_BALLOON_COMPACTION)) b_dev_info.migratepage = cmm_migratepage; diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index df2756c071dae..15c1cf5fd249c 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -274,9 +274,6 @@ static unsigned int fill_balloon(struct virtio_balloon *vb, size_t num) set_page_pfns(vb, vb->pfns + vb->num_pfns, page); vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE; - if (!virtio_has_feature(vb->vdev, - VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) - adjust_managed_page_count(page, -1); vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE; } @@ -295,9 +292,6 @@ static void release_pages_balloon(struct virtio_balloon *vb, struct page *page, *next; list_for_each_entry_safe(page, next, pages, lru) { - if (!virtio_has_feature(vb->vdev, - VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) - adjust_managed_page_count(page, 1); list_del(&page->lru); put_page(page); /* balloon reference */ } @@ -839,17 +833,6 @@ static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info, if (!mutex_trylock(&vb->balloon_lock)) return -EAGAIN; - /* - * When we migrate a page to a different zone and adjusted the - * managed page count when inflating, we have to fixup the count of - * both involved zones. - */ - if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM) && - page_zone(page) != page_zone(newpage)) { - adjust_managed_page_count(page, 1); - adjust_managed_page_count(newpage, -1); - } - /* balloon's page migration 1st step -- inflate "newpage" */ vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE; set_page_pfns(vb, vb->pfns, newpage); @@ -958,6 +941,8 @@ static int virtballoon_probe(struct virtio_device *vdev) if (err) goto out_free_vb; + if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) + vb->vb_dev_info.adjust_managed_page_count = true; #ifdef CONFIG_BALLOON_COMPACTION vb->vb_dev_info.migratepage = virtballoon_migratepage; #endif diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h index 7cfe48769239e..3109d3c43d306 100644 --- a/include/linux/balloon_compaction.h +++ b/include/linux/balloon_compaction.h @@ -56,6 +56,7 @@ struct balloon_dev_info { struct list_head pages; /* Pages enqueued & handled to Host */ int (*migratepage)(struct balloon_dev_info *, struct page *newpage, struct page *page, enum migrate_mode mode); + bool adjust_managed_page_count; }; extern struct page *balloon_page_alloc(void); @@ -73,6 +74,7 @@ static inline void balloon_devinfo_init(struct balloon_dev_info *balloon) spin_lock_init(&balloon->pages_lock); INIT_LIST_HEAD(&balloon->pages); balloon->migratepage = NULL; + balloon->adjust_managed_page_count = false; } #ifdef CONFIG_BALLOON_COMPACTION diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c index 764fa25dc4bd1..4fe2a0cff69ec 100644 --- a/mm/balloon_compaction.c +++ b/mm/balloon_compaction.c @@ -23,6 +23,8 @@ static void balloon_page_enqueue_one(struct balloon_dev_info *b_dev_info, BUG_ON(!trylock_page(page)); balloon_page_insert(b_dev_info, page); unlock_page(page); + if (b_dev_info->adjust_managed_page_count) + adjust_managed_page_count(page, -1); __count_vm_event(BALLOON_INFLATE); inc_node_page_state(page, NR_BALLOON_PAGES); } @@ -95,6 +97,8 @@ size_t balloon_page_list_dequeue(struct balloon_dev_info *b_dev_info, continue; list_del(&page->lru); + if (b_dev_info->adjust_managed_page_count) + adjust_managed_page_count(page, 1); balloon_page_finalize(page); __count_vm_event(BALLOON_DEFLATE); list_add(&page->lru, pages); @@ -264,9 +268,22 @@ static int balloon_page_migrate(struct page *newpage, struct page *page, get_page(newpage); balloon_page_insert(b_dev_info, newpage); __count_vm_event(BALLOON_MIGRATE); + + if (b_dev_info->adjust_managed_page_count && + page_zone(page) != page_zone(newpage)) { + /* + * When we migrate a page to a different zone we + * have to fixup the count of both involved zones. + */ + adjust_managed_page_count(page, 1); + adjust_managed_page_count(newpage, -1); + } } else { /* Old page was deflated but new page not inflated. */ __count_vm_event(BALLOON_DEFLATE); + + if (b_dev_info->adjust_managed_page_count) + adjust_managed_page_count(page, 1); } b_dev_info->isolated_pages--; -- 2.52.0