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AJvYcCVlRvPEyO5lTmgmcn3EAB/NDP9tIXix+Sz5uGG0jlE2VGESl13iNujukIa53P8Iphr0PP6O1xz1yrJRSPANe7HTyPA= X-Gm-Message-State: AOJu0Yx+2MYSWkjW1yF5R1GtHHyW8Bxq9R4ERQOxr0HZ4Q9c1uO5fkgj on9RQbTbHXxOP7EVeWk2IW8+Ep42CABdHc+6vYGMIQZfoKyBH0tNhXhlRfaXBdQM3N7GT2Cr/Vu 23BMK3NjoI0ZwrzNQONZBAlSmvyM= X-Google-Smtp-Source: AGHT+IFEAo7JXInCUEDzKmhn9ExTdgovAuIzNcL9oD/qeIwarBnvFXlJaxHzph8F5vyLFGOC6JR5iidAyppUu3Me2hs= X-Received: by 2002:a05:6512:684:b0:51c:590f:4305 with SMTP id 2adb3069b0e04-5220e3736c2mr404774e87.8.1715310385488; Thu, 09 May 2024 20:06:25 -0700 (PDT) MIME-Version: 1.0 References: <20240509023937.1090421-1-zhaoyang.huang@unisoc.com> <20240509023937.1090421-3-zhaoyang.huang@unisoc.com> In-Reply-To: From: Zhaoyang Huang Date: Fri, 10 May 2024 11:06:14 +0800 Message-ID: Subject: Re: [RFC PATCH 2/2] mm: introduce budgt control in readahead To: Christoph Hellwig Cc: "zhaoyang.huang" , Andrew Morton , Matthew Wilcox , Jens Axboe , Tejun Heo , Josef Bacik , Baolin Wang , linux-mm@kvack.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, steve.kang@unisoc.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: ebrzawwd41miydg5yimutfkte7pgcmwc X-Rspam-User: X-Rspamd-Queue-Id: 788B914001D X-Rspamd-Server: rspam05 X-HE-Tag: 1715310387-501215 X-HE-Meta: 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 5liWWTbQ ZQEG1LwduQWUefX3QHryk7SbetfwRCUZXE6Im/pZpl7852us8tpAEdm1oNWOV1MOeEA9q99VsZWACsJg5UWTMk+a+D8PDH5b7Ar/KgdDpOTZBHb5zqe1LZ2t+fdGz1aytawZFs+6m8Ft6TXHu+Aui+wW8gRakON2az9Ciq3ZUWCjyeRwzGh1lsapHaZ0R2ZTKKlqXnoYFX5uTyWzaYO4ETZGp1MNjBbvaSMSgTEPNQZcuOf0dd9Ul/o7buVfruiXpZbByZQbI4HVLzwSpDHjFTKthqnBOTmqO0cYKMF59jLm+QZJGeazNkHzZFNlF/BrSvjDzq+bVUD5aimKJjcAY6WDDkl9Mas+GvG95urKIhc47yNJ2i2dEj2/cWFUEArXfKYczRErwfinuwj7kBQvskR+8m18GJDGb6bqM X-Bogosity: Ham, tests=bogofilter, spamicity=0.000163, 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 Thu, May 9, 2024 at 8:40=E2=80=AFPM Christoph Hellwig wrote: > > > + unsigned long budgt =3D inode->i_sb->s_bdev ? > > + blk_throttle_budgt(inode->i_sb->s_bdev) : 0; > > The readahead code is used for all file systems, you can't just call > into block layer code here. > ok. I would like to know any suggestions on introducing throttle budget control into readahead which actually works as a negative feedback path. IMO, negative feedback is a good methodology which has been used in scheduler(EAS) and thermal control(IPA) and memory(MGLRU). I would like to suggest to have a try on have it work cross the boundary of memory and block layer. vfs_read / page fault | readahead <---------| | | aops->readpages | | | block_layer------------