lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Fri, 20 Nov 2020 01:20:17 +0000 From: Matthew Wilcox <willy@...radead.org> To: Pavel Begunkov <asml.silence@...il.com> Cc: linux-fsdevel@...r.kernel.org, Alexander Viro <viro@...iv.linux.org.uk>, Jens Axboe <axboe@...nel.dk>, linux-block@...r.kernel.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH v2 1/2] iov_iter: optimise iov_iter_npages for bvec On Thu, Nov 19, 2020 at 11:24:38PM +0000, Pavel Begunkov wrote: > The block layer spends quite a while in iov_iter_npages(), but for the > bvec case the number of pages is already known and stored in > iter->nr_segs, so it can be returned immediately as an optimisation Er ... no, it doesn't. nr_segs is the number of bvecs. Each bvec can store up to 4GB of contiguous physical memory.
Powered by blists - more mailing lists