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d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=2n+TfLDFDLNm1diUWlliMMrU6aXYUGrKG5oiOA73RuM=; b=gDd0jQy64JGIXyojXoAchacRmS/NF8RV0jJUTLr/pKRDaarZLpFF6HIb37ftALVze5 2OZDcte8E7nktUvcraHxiq7vbUuVpK6gK3govXUELBFBl3OHuwfEffRkQS5aCjHUQP+y YZHY0WM2+V5yvnWa6YP8Qf78ZhMDMC1aUz+i4oJXVJJxMy1Vy2QxPrqSbj0pNQURrI32 TKvCSy2qq5/8L5/r7sfrIJIlGx/k807W1I0DmTVA1IA8UkgxUTzt3/ojy4my7Bfepk31 IoiC7C0mca7wQp5BwWFqbs1T4ZpO8L3AGtq3pkpyh8XKQ2OFO+mqaTYgUZufdVItw8Ya Csbw== X-Gm-Message-State: AOAM533WSfSbd1lyREjMx5mP38WOThtRkdITvp6HUyuH32ErbCrDc6JK HtQSxg0Ii9OpW/CHWDvwkdxLaX/Ri35xwzUHys/4Jg== X-Google-Smtp-Source: ABdhPJznc/owu1hxJL41j5B5a6dDFIOdywzccIIq1gAUl367BYKTwf7Bu55aydheHRrc7/qx2xL6cFSIWrgqJpGJNyM= X-Received: by 2002:a2e:240e:: with SMTP id k14mr5036822ljk.332.1606538582329; Fri, 27 Nov 2020 20:43:02 -0800 (PST) MIME-Version: 1.0 References: <20201127041405.3459198-1-guro@fb.com> <20201127161828.GD840171@carbon.dhcp.thefacebook.com> In-Reply-To: <20201127161828.GD840171@carbon.dhcp.thefacebook.com> From: Shakeel Butt Date: Fri, 27 Nov 2020 20:42:51 -0800 Message-ID: Subject: Re: [PATCH] mm: memcg/slab: fix obj_cgroup_charge() return value handling To: Roman Gushchin Cc: Andrew Morton , Linux MM , Johannes Weiner , Michal Hocko , LKML , Kernel Team , stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Nov 27, 2020 at 8:18 AM Roman Gushchin wrote: > > On Thu, Nov 26, 2020 at 09:55:24PM -0800, Shakeel Butt wrote: > > On Thu, Nov 26, 2020 at 8:14 PM Roman Gushchin wrote: > > > > > > Commit 10befea91b61 ("mm: memcg/slab: use a single set of kmem_caches > > > for all allocations") introduced a regression into the handling of the > > > obj_cgroup_charge() return value. If a non-zero value is returned > > > (indicating of exceeding one of memory.max limits), the allocation > > > should fail, instead of falling back to non-accounted mode. > > > > > > To make the code more readable, move memcg_slab_pre_alloc_hook() > > > and memcg_slab_post_alloc_hook() calling conditions into bodies > > > of these hooks. > > > > > > Fixes: 10befea91b61 ("mm: memcg/slab: use a single set of kmem_caches for all allocations") > > > Signed-off-by: Roman Gushchin > > > Cc: stable@vger.kernel.org > > > --- > > > mm/slab.h | 40 ++++++++++++++++++++++++---------------- > > > 1 file changed, 24 insertions(+), 16 deletions(-) > > > > > > diff --git a/mm/slab.h b/mm/slab.h > > > index 59aeb0d9f11b..5dc89d8fb05e 100644 > > > --- a/mm/slab.h > > > +++ b/mm/slab.h > > > @@ -257,22 +257,32 @@ static inline size_t obj_full_size(struct kmem_cache *s) > > > return s->size + sizeof(struct obj_cgroup *); > > > } > > > > > > -static inline struct obj_cgroup *memcg_slab_pre_alloc_hook(struct kmem_cache *s, > > > - size_t objects, > > > - gfp_t flags) > > > +/* > > > + * Returns true if the allocation should fail. > > > > IMO returning false if the allocation should fail makes this more > > clear. Otherwise the patch looks good to me. > > Ok, I agree. Here is an updated version. > > Thank you for looking in! > > -- > > From 456ce03f1c91baf5e2441dce0649e09617437fe4 Mon Sep 17 00:00:00 2001 > From: Roman Gushchin > Date: Thu, 26 Nov 2020 07:39:57 -0800 > Subject: [PATCH v2] mm: memcg/slab: fix obj_cgroup_charge() return value > handling > > Commit 10befea91b61 ("mm: memcg/slab: use a single set of kmem_caches > for all allocations") introduced a regression into the handling of the > obj_cgroup_charge() return value. If a non-zero value is returned > (indicating of exceeding one of memory.max limits), the allocation > should fail, instead of falling back to non-accounted mode. > > To make the code more readable, move memcg_slab_pre_alloc_hook() > and memcg_slab_post_alloc_hook() calling conditions into bodies > of these hooks. > > Fixes: 10befea91b61 ("mm: memcg/slab: use a single set of kmem_caches for all allocations") > Signed-off-by: Roman Gushchin > Cc: stable@vger.kernel.org Reviewed-by: Shakeel Butt