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Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pFb2L-0049x3-LQ; Wed, 11 Jan 2023 13:21:01 +0000 Date: Wed, 11 Jan 2023 13:21:01 +0000 From: Matthew Wilcox To: Yunsheng Lin Cc: Jesper Dangaard Brouer , Ilias Apalodimas , netdev@vger.kernel.org, linux-mm@kvack.org, Shakeel Butt Subject: Re: [PATCH v3 00/26] Split netmem from struct page Message-ID: References: <20230111042214.907030-1-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 7AD9F180009 X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: b3noqb1cu1y3p6fgeny38rkeq36jkhc4 X-HE-Tag: 1673443266-965121 X-HE-Meta: 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 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, Jan 11, 2023 at 04:25:46PM +0800, Yunsheng Lin wrote: > On 2023/1/11 12:21, Matthew Wilcox (Oracle) wrote: > > The MM subsystem is trying to reduce struct page to a single pointer. > > The first step towards that is splitting struct page by its individual > > users, as has already been done with folio and slab. This patchset does > > that for netmem which is used for page pools. > > As page pool is only used for rx side in the net stack depending on the > driver, a lot more memory for the net stack is from page_frag_alloc_align(), > kmem cache, etc. > naming it netmem seems a little overkill, perhaps a more specific name for > the page pool? such as pp_cache. > > @Jesper & Ilias > Any better idea? > And it seem some API may need changing too, as we are not pooling 'pages' > now. I raised the question of naming in v1, six weeks ago, and nobody had any better names. Seems a little unfair to ignore the question at first and then bring it up now. I'd hate to miss the merge window because of a late-breaking major request like this. https://lore.kernel.org/netdev/20221130220803.3657490-1-willy@infradead.org/ I'd like to understand what we think we'll do in networking when we trim struct page down to a single pointer, All these usages that aren't from page_pool -- what information does networking need to track per-allocation? Would it make sense for the netmem to describe all memory used by the networking stack, and have allocators other than page_pool also return netmem, or does the normal usage of memory in the net stack not need to track that information? > > Matthew Wilcox (Oracle) (26): > > netmem: Create new type > > netmem: Add utility functions > > page_pool: Add netmem_set_dma_addr() and netmem_get_dma_addr() > > page_pool: Convert page_pool_release_page() to > > page_pool_release_netmem() > > page_pool: Start using netmem in allocation path. > ^ > nit: there is a '.' at the end of patch titile. Thanks, I'll fix that for v4.