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Tue, 23 Mar 2021 22:45:16 -0700 (PDT) Received: from google.com ([2620:15c:211:201:7dfa:1e53:536:7976]) by smtp.gmail.com with ESMTPSA id l10sm945741pfc.125.2021.03.23.22.45.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 23 Mar 2021 22:45:15 -0700 (PDT) Date: Tue, 23 Mar 2021 22:45:13 -0700 From: Minchan Kim To: Matthew Wilcox Cc: Andrew Morton , linux-mm , LKML , gregkh@linuxfoundation.org, surenb@google.com, joaodias@google.com, jhubbard@nvidia.com, digetx@gmail.com Subject: Re: [PATCH v5] mm: cma: support sysfs Message-ID: References: <20210323195050.2577017-1-minchan@kernel.org> <20210324030224.GO1719932@casper.infradead.org> <20210324043434.GP1719932@casper.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210324043434.GP1719932@casper.infradead.org> X-Stat-Signature: 5x3u7jimacyw1af5k37u3i3yytkjqigw X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 20114E0011C5 Received-SPF: none (gmail.com>: No applicable sender policy available) receiver=imf30; identity=mailfrom; envelope-from=""; helo=mail-pg1-f181.google.com; client-ip=209.85.215.181 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1616564715-352205 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 Wed, Mar 24, 2021 at 04:34:34AM +0000, Matthew Wilcox wrote: > On Tue, Mar 23, 2021 at 08:31:31PM -0700, Minchan Kim wrote: > > On Wed, Mar 24, 2021 at 03:02:24AM +0000, Matthew Wilcox wrote: > > > On Tue, Mar 23, 2021 at 12:50:50PM -0700, Minchan Kim wrote: > > > > + /* the number of CMA page successful allocations */ > > > > + atomic64_t nr_pages_succeeded; > > > > > > > +void cma_sysfs_alloc_pages_count(struct cma *cma, size_t count) > > > > +{ > > > > + atomic64_add(count, &cma->nr_pages_succeeded); > > > > +} > > > > > > I don't understand. A size_t is a byte count. But the variable is called > > > 'nr_pages'. So which is it, a byte count or a page count? > > > > It's page count. I followed the cma_alloc interface since it has > > size_t count variable for nr_pages. > > That's very confusing. cma_alloc is wrong; if it needs to be an > unsigned long, that's fine. But it shouldn't be size_t. > > 7.17 of n1256 defines: > > size_t > which is the unsigned integer type of the result of the sizeof operator > > Do you want to submit a patch to fix cma_alloc as well? Sure, but it will be separate patch. > > > Let's go with unsigned long nr_pages: > > void cma_sysfs_alloc_pages_count(struct cma *cma, unsigned long > > nr_pages) > > Works for me! Thanks for review!