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charset=us-ascii Content-Disposition: inline In-Reply-To: <20200501154853.bca4cfb7b2558bd43a4942f3@linux-foundation.org> User-Agent: NeoMutt/20170113 (1.7.2) X-Bogosity: Ham, tests=bogofilter, spamicity=0.001969, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, May 01, 2020 at 03:48:53PM -0700, Andrew Morton wrote: >On Fri, 1 May 2020 01:52:59 +0000 Wei Yang wrote: > >> When the condition is true, there are two possibilities: > >I'm struggling with this one. > >> 1. count == SWAP_MAP_BAD >> 2. count == (SWAP_MAP_MAX & COUNT_CONTINUED) == SWAP_MAP_SHMEM > >I'm not sure what 2. is trying to say. For a start, (SWAP_MAP_MAX & >COUNT_CONTINUED) is zero. I guess it meant "|"? Oops, you are right. It should be (SWAP_MAP_MAX | COUNT_CONTINUED). Sorry for the confusion. > >Also, the return value documentation says we return EINVAL for migration >entries. Where's that happening, or is the comment out of date? > Not paid attention to this. Take look into the code, I don't find a relationship between the swap count and migration. Seems we just make a migration entry but not duplicate it. If my understanding is correct. >> The first case would be filtered by the first if in __swap_duplicate(). >> >> And the second case means this swap entry is for shmem. Since we never >> do another duplication for shmem swap entry. This won't happen neither. > -- Wei Yang Help you, Help me