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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=HLc/Voxttk0K0bVFTOEyEs7YtG6EdmZ9JU6ezjA/V4E=; b=OEW73pbogz3DHzxe++QhucXhHn4xaVblBwqnSgDOV8hhperKmle18unMrdFE3rm9ii WraaJmyCyKH8fm2po84IK+Zhv0AtV6MYrVfbp1UPddBmSTyvKHDIRJLa/uMTjoFfLn0M P8vMBbEQYlSCZuvBZGxJsUG7Cf7zIthjDvnys89nr8PtK58Rcxr20mGKmeBq2VPrqsYi lFnA9XLsqIWJu7VD6dEigMOsGT5kse1oCspNg8rsyGthB0lTD9Ya2BtGLD0tLtErdaEv MQkvdmnN61n++kZMNPH0fdQ1jRtjmVQEbmtGvcK1j/zWeikGQ+JYDODogq1OMdIrfb8E 9Biw== X-Gm-Message-State: AO0yUKX+5//mgyc3A6z2l0+dYf0HEsTQVzyxYHM0JQv+mkEPzWsSRogu xoojvzaN3dYvqV7886MPX9oWa6yUOb99CSNUySs= X-Google-Smtp-Source: AK7set+WOA8AnDxtDT4nbRZMQ4Wlm75cF5E3fHaSldoIhx1lTXHU43C7MRy15kUBNDtFlHQMFCY5a3w/YvSV+VYFV7c= X-Received: by 2002:a05:622a:50c:b0:3b9:a6ca:a603 with SMTP id l12-20020a05622a050c00b003b9a6caa603mr384493qtx.101.1675753363188; Mon, 06 Feb 2023 23:02:43 -0800 (PST) MIME-Version: 1.0 References: <20230202014158.19616-1-laoar.shao@gmail.com> <63ddbfd9ae610_6bb1520861@john.notmuch> In-Reply-To: From: Yafang Shao Date: Tue, 7 Feb 2023 15:02:07 +0800 Message-ID: Subject: Re: [PATCH bpf-next 0/7] bpf, mm: bpf memory usage To: Ho-Ren Chuang Cc: John Fastabend , ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, tj@kernel.org, dennis@kernel.org, cl@linux.com, akpm@linux-foundation.org, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, roman.gushchin@linux.dev, 42.hyeyoo@gmail.com, vbabka@suse.cz, urezki@gmail.com, linux-mm@kvack.org, bpf@vger.kernel.org, hao.xiang@bytedance.com, yifeima@bytedance.com, Xiaoning Ding , horenchuang@bytedance.com Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 0596F20012 X-Rspam-User: X-Stat-Signature: rwgwqofbq593m4scnjqi7y6d6eeaqtaz X-HE-Tag: 1675753363-732440 X-HE-Meta: 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 okALzKx1 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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 Tue, Feb 7, 2023 at 8:49 AM Ho-Ren Chuang wrote: > > Hi Yafang and everyone, > > We've proposed very similar features at https://lore.kernel.org/bpf/CAAYibXgiCOOEY9NvLXbY4ve7pH8xWrZjnczrj6SHy3x_TtOU1g@mail.gmail.com/#t > I have looked through your patchset. Maybe we can use max_entires to show the used_enties for preallocated hashtab? Because for the preallocated hashtab, the memory is already allocated, so it doesn't matter how many entries it is using now. Then we can avoid the runtime overhead which Alexei is worried about. > > We are very excited seeing we are not the only ones eager to have this feature upstream to monitor eBPF map's actual usage. This shows the need for having such an ability in eBPF. > Happy to hear that this feature could help you. I think over time there will be more users who want to monitor the bpf memory usage :) > > Regarding the use cases please also check https://lore.kernel.org/all/CAADnVQLBt0snxv4bKwg1WKQ9wDFbaDCtZ03v1-LjOTYtsKPckQ@mail.gmail.com/#t . We are developing an app to monitor memory footprints used by eBPF programs/maps similar to Linux `top` command. > > > Thank you, > -- Regards Yafang