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[95.203.7.38]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-54120c005besm910045e87.167.2024.12.16.07.55.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Dec 2024 07:55:08 -0800 (PST) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Mon, 16 Dec 2024 16:55:06 +0100 To: Vlastimil Babka Cc: Uladzislau Rezki , linux-mm@kvack.org, "Paul E . McKenney" , Andrew Morton , RCU , LKML , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Oleksiy Avramchenko Subject: Re: [PATCH v2 0/5] Move kvfree_rcu() into SLAB (v2) Message-ID: References: <20241212180208.274813-1-urezki@gmail.com> <17476947-d447-4de3-87bb-97d5f3c0497d@suse.cz> <6fb206de-0185-4026-a6f5-1d150752d8d0@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6fb206de-0185-4026-a6f5-1d150752d8d0@suse.cz> X-Rspamd-Queue-Id: 5AD301A0015 X-Rspam-User: X-Rspamd-Server: rspam07 X-Stat-Signature: 9jo45wcwty9gt48neei9rpq16w8htpfh X-HE-Tag: 1734364480-575005 X-HE-Meta: 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 6bM9q+zw 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.002384, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Dec 16, 2024 at 04:44:41PM +0100, Vlastimil Babka wrote: > On 12/16/24 16:41, Uladzislau Rezki wrote: > > On Mon, Dec 16, 2024 at 03:20:44PM +0100, Vlastimil Babka wrote: > >> On 12/16/24 12:03, Uladzislau Rezki wrote: > >> > On Sun, Dec 15, 2024 at 06:30:02PM +0100, Vlastimil Babka wrote: > >> >> On 12/12/24 19:02, Uladzislau Rezki (Sony) wrote: > >> >> > Hello! > >> >> > > >> >> > This is v2. It is based on the Linux 6.13-rc2. The first version is > >> >> > here: > >> >> > > >> >> > https://lore.kernel.org/linux-mm/20241210164035.3391747-4-urezki@gmail.com/T/ > >> >> > > >> >> > The difference between v1 and v2 is that, the preparation process is > >> >> > done in original place instead and after that there is one final move. > >> >> > >> >> Looks good, will include in slab/for-next > >> >> > >> >> I think patch 5 should add more explanation to the commit message - the > >> >> subthread started by Christoph could provide content :) Can you summarize so > >> >> I can amend the commit log? > >> >> > >> > I will :) > >> > > >> >> Also how about a followup patch moving the rcu-tiny implementation of > >> >> kvfree_call_rcu()? > >> >> > >> > As, Paul already noted, it would make sense. Or just remove a tiny > >> > implementation. > >> > >> AFAICS tiny rcu is for !SMP systems. Do they benefit from the "full" > >> implementation with all the batching etc or would that be unnecessary overhead? > >> > > Yes, it is for a really small systems with low amount of memory. I see > > only one overhead it is about driving objects in pages. For a small > > system it can be critical because we allocate. > > > > From the other hand, for a tiny variant we can modify the normal variant > > by bypassing batching logic, thus do not consume memory(for Tiny case) > > i.e. merge it to a normal kvfree_rcu() path. > > Maybe we could change it to use CONFIG_SLUB_TINY as that has similar use > case (less memory usage on low memory system, tradeoff for worse performance). > Yep, i also was thinking about that without saying it :) -- Uladzislau Rezki