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[180.150.90.198]) by smtp.gmail.com with ESMTPSA id l21-20020a17090a409500b001e85f38bc79sm1742359pjg.41.2022.06.15.06.33.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 15 Jun 2022 06:33:26 -0700 (PDT) Message-ID: Date: Wed, 15 Jun 2022 21:33:22 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [PATCH 1/3] radix-tree: propagate all tags in idr tree Content-Language: en-US To: Christoph Hellwig , Brian Foster Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, onestero@redhat.com References: <20220614180949.102914-1-bfoster@redhat.com> <20220614180949.102914-2-bfoster@redhat.com> From: Ian Kent In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 15/6/22 19:12, Christoph Hellwig wrote: > On Tue, Jun 14, 2022 at 02:09:47PM -0400, Brian Foster wrote: >> The IDR tree has hardcoded tag propagation logic to handle the >> internal IDR_FREE tag and ignore all others. Fix up the hardcoded >> logic to support additional tags. >> >> This is specifically to support a new internal IDR_TGID radix tree >> tag used to improve search efficiency of pids with associated >> PIDTYPE_TGID tasks within a pid namespace. > Wouldn't it make sense to switch over to an xarray here rather > then adding new features to the radix tree? > Might be a dumb question but ... How would the, essentially sparse, pid type PIDTYPE_TGID pids traversal get benefits from an xarray? From what I have seen the searching isn't the real problem, it's the traversal (that, at the moment, does a search 'and' a traversal over a lot of pids to get a relatively small number of them). Ian