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Tue, 10 Mar 2020 23:18:39 -0700 (PDT) Received: from localhost ([2401:fa00:8f:203:5bbb:c872:f2b1:f53b]) by smtp.gmail.com with ESMTPSA id gx7sm4180800pjb.16.2020.03.10.23.18.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Mar 2020 23:18:38 -0700 (PDT) Date: Wed, 11 Mar 2020 15:18:36 +0900 From: Sergey Senozhatsky To: Jaewon Kim Cc: adobriyan@gmail.com, akpm@linux-foundation.org, labbott@redhat.com, sumit.semwal@linaro.org, minchan@kernel.org, ngupta@vflare.org, sergey.senozhatsky.work@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, jaewon31.kim@gmail.com Subject: Re: [RFC PATCH 1/3] proc/meminfo: introduce extra meminfo Message-ID: <20200311061836.GA83589@google.com> References: <20200311034441.23243-1-jaewon31.kim@samsung.com> <20200311034441.23243-2-jaewon31.kim@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200311034441.23243-2-jaewon31.kim@samsung.com> User-Agent: Mutt/1.12.2 (2019-09-21) 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 (20/03/11 12:44), Jaewon Kim wrote: [..] > +#define NAME_SIZE 15 > +#define NAME_BUF_SIZE (NAME_SIZE + 2) /* ':' and '\0' */ > + > +struct extra_meminfo { > + struct list_head list; > + atomic_long_t *val; > + int shift_for_page; > + char name[NAME_BUF_SIZE]; > + char name_pad[NAME_BUF_SIZE]; > +}; > + > +int register_extra_meminfo(atomic_long_t *val, int shift, const char *name) > +{ > + struct extra_meminfo *meminfo, *memtemp; > + int len; > + int error = 0; > + > + meminfo = kzalloc(sizeof(*meminfo), GFP_KERNEL); > + if (!meminfo) { > + error = -ENOMEM; > + goto out; > + } > + > + meminfo->val = val; > + meminfo->shift_for_page = shift; > + strncpy(meminfo->name, name, NAME_SIZE); > + len = strlen(meminfo->name); > + meminfo->name[len] = ':'; > + strncpy(meminfo->name_pad, meminfo->name, NAME_BUF_SIZE); What happens if there is no NULL byte among the first NAME_SIZE bytes of passed `name'? [..] > + spin_lock(&meminfo_lock); Does this need to be a spinlock? -ss