From: SeongJae Park <sjpark@amazon.com>
To: SeongJae Park <sjpark@amazon.com>
Cc: <akpm@linux-foundation.org>, <Jonathan.Cameron@Huawei.com>,
<aarcange@redhat.com>, <acme@kernel.org>,
<alexander.shishkin@linux.intel.com>, <amit@kernel.org>,
<benh@kernel.crashing.org>, <brendan.d.gregg@gmail.com>,
<brendanhiggins@google.com>, <cai@lca.pw>,
<colin.king@canonical.com>, <corbet@lwn.net>, <david@redhat.com>,
<dwmw@amazon.com>, <elver@google.com>, <fan.du@intel.com>,
<foersleo@amazon.de>, <gthelen@google.com>, <irogers@google.com>,
<jolsa@redhat.com>, <kirill@shutemov.name>,
<mark.rutland@arm.com>, <mgorman@suse.de>, <minchan@kernel.org>,
<mingo@redhat.com>, <namhyung@kernel.org>, <peterz@infradead.org>,
<rdunlap@infradead.org>, <riel@surriel.com>,
<rientjes@google.com>, <rostedt@goodmis.org>, <rppt@kernel.org>,
<sblbir@amazon.com>, <shakeelb@google.com>, <shuah@kernel.org>,
<sj38.park@gmail.com>, <snu@amazon.de>, <vbabka@suse.cz>,
<vdavydov.dev@gmail.com>, <yang.shi@linux.alibaba.com>,
<ying.huang@intel.com>, <zgf574564920@gmail.com>,
<linux-damon@amazon.com>, <linux-mm@kvack.org>,
<linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v23 03/15] mm/damon: Adaptively adjust regions
Date: Tue, 19 Jan 2021 19:36:36 +0100 [thread overview]
Message-ID: <20210119183636.327-1-sjpark@amazon.com> (raw)
In-Reply-To: <20201215115448.25633-4-sjpark@amazon.com>
On Tue, 15 Dec 2020 12:54:36 +0100 SeongJae Park <sjpark@amazon.com> wrote:
> From: SeongJae Park <sjpark@amazon.de>
>
> Even somehow the initial monitoring target regions are well constructed
> to fulfill the assumption (pages in same region have similar access
> frequencies), the data access pattern can be dynamically changed. This
> will result in low monitoring quality. To keep the assumption as much
> as possible, DAMON adaptively merges and splits each region based on
> their access frequency.
>
> For each ``aggregation interval``, it compares the access frequencies of
> adjacent regions and merges those if the frequency difference is small.
> Then, after it reports and clears the aggregated access frequency of
> each region, it splits each region into two or three regions if the
> total number of regions will not exceed the user-specified maximum
> number of regions after the split.
>
> In this way, DAMON provides its best-effort quality and minimal overhead
> while keeping the upper-bound overhead that users set.
>
> Signed-off-by: SeongJae Park <sjpark@amazon.de>
> Reviewed-by: Leonard Foerster <foersleo@amazon.de>
> ---
> include/linux/damon.h | 41 +++++---
> mm/damon/core.c | 220 ++++++++++++++++++++++++++++++++++++++++--
> 2 files changed, 240 insertions(+), 21 deletions(-)
>
[...]
> diff --git a/mm/damon/core.c b/mm/damon/core.c
> index 167487e75737..0f9beb60d9dd 100644
> --- a/mm/damon/core.c
> +++ b/mm/damon/core.c
[...]
> +
> +/*
> + * Split a region in two
> + *
> + * r the region to be split
> + * sz_r size of the first sub-region that will be made
> + */
> +static void damon_split_region_at(struct damon_ctx *ctx,
> + struct damon_region *r, unsigned long sz_r)
> +{
> + struct damon_region *new;
> +
> + new = damon_new_region(r->ar.start + sz_r, r->ar.end);
Coverity Static Analysis Security Testing (SAST) by Synopsys, Inc. found that
'damon_new_region()' could return NULL in case of memory allocation failure,
but NULL check for 'new' is missed here. I will add the check in the next
version.
> + r->ar.end = new->ar.start;
> +
> + damon_insert_region(new, r, damon_next_region(r));
> +}
[...]
Thanks,
SeongJae Park
next prev parent reply other threads:[~2021-01-19 18:37 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-15 11:54 [PATCH v23 00/15] Introduce Data Access MONitor (DAMON) SeongJae Park
2020-12-15 11:54 ` [PATCH v23 01/15] mm: " SeongJae Park
2020-12-23 15:11 ` Shakeel Butt
2020-12-23 16:33 ` SeongJae Park
2020-12-23 22:49 ` Shakeel Butt
2020-12-24 7:02 ` SeongJae Park
2020-12-15 11:54 ` [PATCH v23 02/15] mm/damon/core: Implement region-based sampling SeongJae Park
2021-02-01 17:37 ` Shakeel Butt
2021-02-02 9:17 ` SeongJae Park
2020-12-15 11:54 ` [PATCH v23 03/15] mm/damon: Adaptively adjust regions SeongJae Park
2021-01-19 18:36 ` SeongJae Park [this message]
2021-02-01 17:37 ` Shakeel Butt
2021-02-02 9:39 ` SeongJae Park
2020-12-15 11:54 ` [PATCH v23 04/15] mm/idle_page_tracking: Make PG_idle reusable SeongJae Park
2020-12-23 15:11 ` Shakeel Butt
2020-12-15 11:54 ` [PATCH v23 05/15] mm/damon: Implement primitives for the virtual memory address spaces SeongJae Park
2020-12-23 15:31 ` Shakeel Butt
2020-12-23 16:47 ` SeongJae Park
2020-12-23 22:54 ` Shakeel Butt
2020-12-24 7:11 ` SeongJae Park
2021-01-27 16:56 ` SeongJae Park
2021-01-27 17:02 ` Shakeel Butt
2020-12-15 11:54 ` [PATCH v23 06/15] mm/damon: Add a tracepoint SeongJae Park
2020-12-15 11:54 ` [PATCH v23 07/15] mm/damon: Implement a debugfs-based user space interface SeongJae Park
2021-02-01 17:37 ` Shakeel Butt
2021-02-02 10:00 ` SeongJae Park
2020-12-15 11:54 ` [PATCH v23 08/15] mm/damon/dbgfs: Implement recording feature SeongJae Park
2020-12-15 11:54 ` [PATCH v23 09/15] mm/damon/dbgfs: Export kdamond pid to the user space SeongJae Park
2020-12-15 11:54 ` [PATCH v23 10/15] mm/damon/dbgfs: Support multiple contexts SeongJae Park
2021-02-02 12:27 ` SeongJae Park
2020-12-15 11:54 ` [PATCH v23 11/15] tools: Introduce a minimal user-space tool for DAMON SeongJae Park
2020-12-23 18:37 ` SeongJae Park
2020-12-23 22:56 ` Shakeel Butt
2020-12-24 7:13 ` SeongJae Park
2020-12-15 11:54 ` [PATCH v23 12/15] Documentation: Add documents " SeongJae Park
2020-12-15 11:54 ` [PATCH v23 13/15] mm/damon: Add kunit tests SeongJae Park
2020-12-15 11:54 ` [PATCH v23 14/15] mm/damon: Add user space selftests SeongJae Park
2020-12-15 11:54 ` [PATCH v23 15/15] MAINTAINERS: Update for DAMON SeongJae Park
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