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charset=us-ascii Content-Disposition: inline In-Reply-To: <9c475803276ea2b32cadc8f72d397c180475d0cc.camel@perches.com> 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 Mon, Feb 01, 2021 at 10:51:03AM -0800, Joe Perches wrote: > On Mon, 2021-02-01 at 14:15 +0000, Matthew Wilcox wrote: > > On Mon, Feb 01, 2021 at 07:56:10PM +0800, Yafang Shao wrote: > > > - Before the patch, > > > [ 6343.396602] Slab 0x000000004382e02b objects=33 used=3 fp=0x000000009ae06ffc flags=0x17ffffc0010200(slab|head) > > > > > > - After the patch, > > > [ 6871.296131] Slab 0x00000000c0e19a37 objects=33 used=3 fp=0x00000000c4902159 flags=0x17ffffc0010200(Node 0,Zone 2,Lastcpupid 0x1fffff,slab|head) > > > > I would suggest it will be easier to parse as: > > > > flags=0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff) > > > > That should alleviate the concerns about debugfs format change -- we've > > never guaranteed that flag names won't change, and they now look enough > > like flags that parsers shouldn't fall over them. > > Seems sensible and would make the generating code simpler too. > > But is it worth the vsprintf code expansion for the 5 current uses? > > mm/debug.c: pr_warn("%sflags: %#lx(%pGp)%s\n", type, head->flags, &head->flags, > mm/memory-failure.c: pr_info("soft offline: %#lx: %s migration failed %d, type %lx (%pGp)\n", > mm/memory-failure.c: pr_info("soft offline: %#lx: %s isolation failed, page count %d, type %lx (%pGp)\n", > mm/memory-failure.c: pr_info("%s: %#lx: unknown page type: %lx (%pGp)\n", > mm/page_owner.c: "PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n", > > Wouldn't it be more sensible just to put this code in a new function > call in mm? Does it matter whether the code lives in vsprintf.c or mm/debug.c? It's built into the kernel core either way. I'm not a huge fan of the current way %pFoo is handled, but unless/until it's drastically revised, I don't think this proposed patch makes anything worse.