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charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 8A1A116002C X-Stat-Signature: 56inynd7xrtq7otscxxozqjr5h1h8h9q X-Rspam-User: X-HE-Tag: 1686831413-777303 X-HE-Meta: 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 5ZJsh0Ji sffNZ6o1OHaNMxJZoylH4RD+1j1Zfr42Rl3zoiD74dD6m75z0wE+HTLqUGRzfa6BTlnwDsXhIDpsOlIii/35ysv8kSZN5FQkErmpUXz4DqJU7N5J5U73tLZrnX+frGpZV3nedhB6vkCuBSySDL9eB7mnd8A== 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 Thu 15-06-23 19:58:37, 贺中坤 wrote: > Hi michal, glad to hear from you. > > > I am not really deeply familiar with zram implementation nor usage but > > how is the above allocation going to be charged without __GFP_ACCOUNT in > > the gfp mask? > > Yes，zs_malloc() did not charge compressed memory, even if we add this gfp. > so we need to implement this function in this patchset. But this flag should be > used to enable this feature. Let me check I understand. This patch on its own doesn't really do anything. You need the zs_malloc support implemented in patch 3 for this to have any effect. Even with that in place the zs_malloc doesn't follow the __GFP_ACCOUNT scheme we use for allocation tracking. Correct? > > Also what exactly is going to happen for the swap backed by the zram > > device? Your memcg might be hitting the hard limit and therefore > > swapping out. Wouldn't zs_malloc fail very likely under that condition > > making the swap effectively unusable? > > This is the key point, as i said above, zs_malloc() did not charge > compressed memory, > so zs_malloc will not fail under that condition. if the zram swap is > large enough, zs_malloc > never fails unless system OOM. so memory.max will be invalidated. I do not think this is answering my question. Or maybe I just misunderstand. Let me try again. Say you have a memcg under hard limit pressure so any further charge is going to fail. How can you reasonably implement zram back swapout if the memory is charged? -- Michal Hocko SUSE Labs