From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Schatzberg Subject: [PATCH 2/3] mm: Charge active memcg when no mm is set Date: Tue, 16 Mar 2021 08:36:51 -0700 Message-ID: <20210316153655.500806-3-schatzberg.dan@gmail.com> References: <20210316153655.500806-1-schatzberg.dan@gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Io4/SuSrOnO2lgbZBjKm6Sy30ngmcZaMUy5F+H9fpyg=; b=litRM2T0M677dAg8+HS9+0ucinGZ/dprpSboNx4ygkFJPc0HA7LeXLHFrv7Q9m7k79 aUxF39PH+bvWZtQ0icKUCN/4ShHLXO2+bh72cKKbvhbVjEJDHIL0WCz61My8fhcto88B QvLWU0tlpdH7qaNFpUHjdjkJ7Asl4Hi0b3cRIqZ93FsHXczVR7keUqqqpiMBaIlsoJ5m HokRsWiOoqXWTO98zQWkfe4xQC3jTTfs0+bMx0aKRlA47CnKyFscvmsBxs3Z7jKLx+jd 1HGoBPab+GGGBMBfNjofRaLQVJrgvBq2KfmpJBH1thj4ZTg7KHcg32MgwI4IJ2rSfJh/ 2noQ== In-Reply-To: <20210316153655.500806-1-schatzberg.dan@gmail.com> List-ID: Content-Type: text/plain; charset="us-ascii" To: Cc: Jens Axboe , Tejun Heo , Zefan Li , Johannes Weiner , Andrew Morton , Michal Hocko , Vladimir Davydov , Hugh Dickins , Shakeel Butt , Roman Gushchin , Muchun Song , Alex Shi , Alexander Duyck , Chris Down , Yafang Shao , Wei Yang , "open list:BLOCK LAYER" , open list , "open list:CONTROL GROUP CGROUP" , linux- memalloc_use_memcg() worked for kernel allocations but was silently ignored for user pages. This patch establishes a precedence order for who gets charged: 1. If there is a memcg associated with the page already, that memcg is charged. This happens during swapin. 2. If an explicit mm is passed, mm->memcg is charged. This happens during page faults, which can be triggered in remote VMs (eg gup). 3. Otherwise consult the current process context. If it has configured a current->active_memcg, use that. Otherwise, current->mm->memcg. Previously, if a NULL mm was passed to mem_cgroup_try_charge (case 3) it would always charge the root cgroup. Now it looks up the current active_memcg first (falling back to charging the root cgroup if not set). Signed-off-by: Dan Schatzberg Acked-by: Johannes Weiner Acked-by: Tejun Heo Acked-by: Chris Down Reviewed-by: Shakeel Butt --- mm/filemap.c | 2 +- mm/memcontrol.c | 14 +++++++++++--- mm/shmem.c | 4 ++-- 3 files changed, 14 insertions(+), 6 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 43700480d897..5135f330f05c 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -843,7 +843,7 @@ noinline int __add_to_page_cache_locked(struct page *page, page->index = offset; if (!huge) { - error = mem_cgroup_charge(page, current->mm, gfp); + error = mem_cgroup_charge(page, NULL, gfp); if (error) goto error; charged = true; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e064ac0d850a..9a1b23ed3412 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6690,7 +6690,8 @@ void mem_cgroup_calculate_protection(struct mem_cgroup *root, * @gfp_mask: reclaim mode * * Try to charge @page to the memcg that @mm belongs to, reclaiming - * pages according to @gfp_mask if necessary. + * pages according to @gfp_mask if necessary. if @mm is NULL, try to + * charge to the active memcg. * * Returns 0 on success. Otherwise, an error code is returned. */ @@ -6726,8 +6727,15 @@ int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) rcu_read_unlock(); } - if (!memcg) - memcg = get_mem_cgroup_from_mm(mm); + if (!memcg) { + if (!mm) { + memcg = get_mem_cgroup_from_current(); + if (!memcg) + memcg = get_mem_cgroup_from_mm(current->mm); + } else { + memcg = get_mem_cgroup_from_mm(mm); + } + } ret = try_charge(memcg, gfp_mask, nr_pages); if (ret) diff --git a/mm/shmem.c b/mm/shmem.c index b2db4ed0fbc7..353b362c370e 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1695,7 +1695,7 @@ static int shmem_swapin_page(struct inode *inode, pgoff_t index, { struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); - struct mm_struct *charge_mm = vma ? vma->vm_mm : current->mm; + struct mm_struct *charge_mm = vma ? vma->vm_mm : NULL; struct page *page; swp_entry_t swap; int error; @@ -1816,7 +1816,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, } sbinfo = SHMEM_SB(inode->i_sb); - charge_mm = vma ? vma->vm_mm : current->mm; + charge_mm = vma ? vma->vm_mm : NULL; page = pagecache_get_page(mapping, index, FGP_ENTRY | FGP_HEAD | FGP_LOCK, 0); -- 2.30.2