Date:   Mon, 20 Feb 2023 15:17:02 +0200
From:   Mike Rapoport <rppt@kernel.org>
To:     Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc:     Peter Xu <peterx@redhat.com>, David Hildenbrand <david@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        =?utf-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= <emmir@google.com>,
        Andrei Vagin <avagin@gmail.com>,
        Danylo Mocherniuk <mdanylo@google.com>,
        Paul Gofman <pgofman@codeweavers.com>,
        Cyrill Gorcunov <gorcunov@gmail.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Shuah Khan <shuah@kernel.org>,
        Christian Brauner <brauner@kernel.org>,
        Yang Shi <shy828301@gmail.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        "Liam R . Howlett" <Liam.Howlett@oracle.com>,
        Yun Zhou <yun.zhou@windriver.com>,
        Suren Baghdasaryan <surenb@google.com>,
        Alex Sierra <alex.sierra@amd.com>,
        Matthew Wilcox <willy@infradead.org>,
        Pasha Tatashin <pasha.tatashin@soleen.com>,
        Nadav Amit <namit@vmware.com>,
        Axel Rasmussen <axelrasmussen@google.com>,
        "Gustavo A . R . Silva" <gustavoars@kernel.org>,
        Dan Williams <dan.j.williams@intel.com>,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
        Greg KH <gregkh@linuxfoundation.org>, kernel@collabora.com
Subject: Re: [PATCH v10 3/6] fs/proc/task_mmu: Implement IOCTL to get and/or
 the clear info about PTEs
Message-ID: <Y/NyzkiZPTBi3Rhc@kernel.org>
References: <20230202112915.867409-1-usama.anjum@collabora.com>
 <20230202112915.867409-4-usama.anjum@collabora.com>
 <Y+9SjpwS9LsRKQz0@kernel.org>
 <05962e92-9d14-eaf9-2e0b-d683986c9d7f@collabora.com>
 <da84e16e-ba8f-db2a-fbc5-c05fe730758c@collabora.com>
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On Mon, Feb 20, 2023 at 04:38:10PM +0500, Muhammad Usama Anjum wrote:
> On 2/20/23 3:38 PM, Muhammad Usama Anjum wrote:
> >>> +#define PAGEMAP_BITS_ALL		(PAGE_IS_WRITTEN | PAGE_IS_FILE |	\
> >>> +					 PAGE_IS_PRESENT | PAGE_IS_SWAPPED)
> >>> +#define PAGEMAP_NON_WRITTEN_BITS	(PAGE_IS_FILE |	PAGE_IS_PRESENT | PAGE_IS_SWAPPED)
> >>> +#define IS_WP_ENGAGE_OP(a)		(a->flags & PAGEMAP_WP_ENGAGE)
> >>> +#define IS_GET_OP(a)			(a->vec)
> >>> +#define HAS_NO_SPACE(p)			(p->max_pages && (p->found_pages == p->max_pages))
> >>> +
> >>> +#define PAGEMAP_SCAN_BITMAP(wt, file, present, swap)	\
> >>> +	(wt | file << 1 | present << 2 | swap << 3)
> >>> +#define IS_WT_REQUIRED(a)				\
> >>> +	((a->required_mask & PAGE_IS_WRITTEN) ||	\
> >>> +	 (a->anyof_mask & PAGE_IS_WRITTEN))
> >> All these macros are specific to pagemap_scan_ioctl() and should be
> >> namespaced accordingly, e.g. PM_SCAN_BITS_ALL, PM_SCAN_BITMAP etc.
> >>
> >> Also, IS_<opname>_OP() will be more readable as PM_SCAN_OP_IS_<opname> and
> >> I'd suggest to open code IS_WP_ENGAGE_OP() and IS_GET_OP() and make
> >> HAS_NO_SPACE() and IS_WT_REQUIRED() static inlines rather than macros.
> > Will do in next version.
> > 
> 
> IS_WP_ENGAGE_OP() and IS_GET_OP() which can be renamed to
> PM_SCAN_OP_IS_WP() and PM_SCAN_OP_IS_GET() seem better to me instead of
> open code as they seem more readable to me. I can open code if you insist.

I'd suggest to see how the rework of pagemap_scan_pmd_entry() paves out. An
open-coded '&' is surely clearer than a macro/function, but if it's buried
in a long sequence of conditions, it may be not such clear win.
 
> -- 
> BR,
> Muhammad Usama Anjum

-- 
Sincerely yours,
Mike.