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h=Date:From:To:Cc:Subject:References:In-Reply-To; b=h9xiN3w6tQaZmnlGlFXHoQYdpAhIdrU1SCwWBhN4fRfNjkM+xDQIPj2Pba9imBt8x SrGL0Hayefiwa7HkLpIrlkOPy4h09Ukw3bDyV8IpF+nGgbb9hZNWvmEkP1GbwkYUsl wB5jx8genrtWxC5qMhpd3wEXiP7cpXpn/Cj7Zt3eSdLoqW3fSoHZyJlQ2fEPRvz1gI PVDFENGYdlYYuvtD6FgjB5EscgrFiYvWXUrcpjr1ASmO9dE+/N31CsETmVpuRSraZP 8pO4w/TgE2wcEn82+N9jJoSQP9WPVgUBlZmOLJmDPZPHKRlsmuYX4fSfJL8a1NmcfC 2rJqxQ61582SA== Date: Tue, 10 Nov 2026 17:03:25 +0000 From: Yosry Ahmed To: Sergey Senozhatsky Cc: Andrew Morton , Nhat Pham , Yosry Ahmed , Johannes Weiner , Brian Geffon , Minchan Kim , Richard Chang , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2 11/11] zsmalloc: populate new zspage outside class->lock in zs_store() Message-ID: References: <20261110054836.1515030-1-senozhatsky@chromium.org> <20261110054836.1515030-12-senozhatsky@chromium.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261110054836.1515030-12-senozhatsky@chromium.org> X-Stat-Signature: zcfbp3wbdkrt83go9rkrsehg3i7ddt77 X-Rspamd-Queue-Id: 894E31C000F X-Rspam-User: X-Rspamd-Server: rspam11 X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-HE-Tag: 1794330208-224803 X-HE-Meta: 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 qAEbizgp NNaIaxO4X338GvFZ72gO7NWPJqPxvz3kO9nWlKKixaFH731aQAFRdJLaH6zB6LlqYY3cjoDZyPKLbFcL8Y5cwa663OITcf0F1tWTWzaR2zZLGzWiRD4RwQgyG/iBkhAgHtVog7KJ/kdD2IY84KQ8fTzvKo9ExLKaBjxohg7yWqbvHJesp3s5FYz1pCw8hxIwsKD3pvWQLKBsLbUXoUeaqU0rw5Uv4AuEHve+Ry7pZ7A/Daf57BCQ+duG0g/layw096yVvm/69RqSjbSkB/RYyKdKFaiwlT69Oqci6yJNvMTMxzSZ23M8NjpX+bHBDZD0PH4W2XkoQsFaOkPjtSsb7sZ/04Q== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Tue, Nov 10, 2026 at 02:48:16PM +0900, Sergey Senozhatsky wrote: > A new zspage is not on class fullness lists and is not movable until > zs_store() calls insert_zspage() and SetZsPageMovable(), so neither > other zs_store() callers nor compaction and page migration can see it. > Nobody else has the handle yet either. > > So for a new zspage allocate the object and copy the data before we > take class->lock, and don't take zspage read lock. This makes > class->lock critical section shorter and saves a zspage lock/unlock. > > Suggested-by: Yosry Ahmed > Signed-off-by: Sergey Senozhatsky LGTM: Reviewed-by: Yosry Ahmed