From: Johannes Weiner <hannes@cmpxchg.org>
To: Suren Baghdasaryan <surenb@google.com>
Cc: tj@kernel.org, mhocko@kernel.org, vdavydov.dev@gmail.com,
akpm@linux-foundation.org, shakeelb@google.com, guro@fb.com,
songmuchun@bytedance.com, shy828301@gmail.com, alexs@kernel.org,
alexander.h.duyck@linux.intel.com, richard.weiyang@gmail.com,
vbabka@suse.cz, axboe@kernel.dk, iamjoonsoo.kim@lge.com,
david@redhat.com, willy@infradead.org, apopple@nvidia.com,
minchan@kernel.org, linmiaohe@huawei.com,
linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
linux-mm@kvack.org, kernel-team@android.com
Subject: Re: [PATCH 2/3] mm, memcg: inline mem_cgroup_{charge/uncharge} to improve disabled memcg config
Date: Fri, 9 Jul 2021 10:48:48 -0400 [thread overview]
Message-ID: <YOhh0IabpRk/W/qR@cmpxchg.org> (raw)
In-Reply-To: <20210709000509.2618345-3-surenb@google.com>
On Thu, Jul 08, 2021 at 05:05:08PM -0700, Suren Baghdasaryan wrote:
> Inline mem_cgroup_{charge/uncharge} and mem_cgroup_uncharge_list functions
> functions to perform mem_cgroup_disabled static key check inline before
> calling the main body of the function. This minimizes the memcg overhead
> in the pagefault and exit_mmap paths when memcgs are disabled using
> cgroup_disable=memory command-line option.
> This change results in ~0.4% overhead reduction when running PFT test
> comparing {CONFIG_MEMCG=n} against {CONFIG_MEMCG=y, cgroup_disable=memory}
> configurationon on an 8-core ARM64 Android device.
>
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Sounds reasonable to me as well. One comment:
> @@ -693,13 +693,59 @@ static inline bool mem_cgroup_below_min(struct mem_cgroup *memcg)
> page_counter_read(&memcg->memory);
> }
>
> -int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask);
> +struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm);
> +
> +int __mem_cgroup_charge(struct page *page, struct mem_cgroup *memcg,
> + gfp_t gfp);
> +/**
> + * mem_cgroup_charge - charge a newly allocated page to a cgroup
> + * @page: page to charge
> + * @mm: mm context of the victim
> + * @gfp_mask: reclaim mode
> + *
> + * Try to charge @page to the memcg that @mm belongs to, reclaiming
> + * pages according to @gfp_mask if necessary. if @mm is NULL, try to
> + * charge to the active memcg.
> + *
> + * Do not use this for pages allocated for swapin.
> + *
> + * Returns 0 on success. Otherwise, an error code is returned.
> + */
> +static inline int mem_cgroup_charge(struct page *page, struct mm_struct *mm,
> + gfp_t gfp_mask)
> +{
> + struct mem_cgroup *memcg;
> + int ret;
> +
> + if (mem_cgroup_disabled())
> + return 0;
> +
> + memcg = get_mem_cgroup_from_mm(mm);
> + ret = __mem_cgroup_charge(page, memcg, gfp_mask);
> + css_put(&memcg->css);
> +
> + return ret;
Why not do
int __mem_cgroup_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask);
static inline int mem_cgroup_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask)
{
if (mem_cgroup_disabled())
return 0;
return __mem_cgroup_charge(page, memcg, gfp_mask);
}
like in the other cases as well?
That would avoid inlining two separate function calls into all the
callsites...
There is an (internal) __mem_cgroup_charge() already, but you can
rename it charge_memcg().
next prev parent reply other threads:[~2021-07-09 14:48 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-09 0:05 [PATCH 0/3] mm, memcg: Optimizations to minimize overhead when memcgs are disabled Suren Baghdasaryan
2021-07-09 0:05 ` [PATCH 1/3] mm, memcg: add mem_cgroup_disabled checks in vmpressure and swap-related functions Suren Baghdasaryan
2021-07-09 14:41 ` Johannes Weiner
2021-07-09 16:00 ` Shakeel Butt
2021-07-09 0:05 ` [PATCH 2/3] mm, memcg: inline mem_cgroup_{charge/uncharge} to improve disabled memcg config Suren Baghdasaryan
2021-07-09 14:48 ` Johannes Weiner [this message]
2021-07-09 15:18 ` Suren Baghdasaryan
2021-07-09 17:17 ` Suren Baghdasaryan
2021-07-09 0:05 ` [PATCH 3/3] mm, memcg: inline swap-related functions " Suren Baghdasaryan
2021-07-09 14:49 ` Johannes Weiner
2021-07-09 16:05 ` Shakeel Butt
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