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Peter Anvin" , Thomas Gleixner , LKML , X86 ML , Borislav Petkov , "Woodhouse, David" , daniel@iogearbox.net, guro@fb.com Subject: Re: [RFC PATCH 1/5] x86: introduce preemption disable prefix Message-ID: <20181019050051.bs2kk4sagu7hpwxx@ast-mbp.dhcp.thefacebook.com> References: <20181018005420.82993-1-namit@vmware.com> <20181018005420.82993-2-namit@vmware.com> <07255D2B-0243-4254-B62A-37050C44207E@vmware.com> <925F22EA-F8CB-4194-B96B-378409ED7918@vmware.com> <2626124E-7344-42F3-AD07-0BB34D62A9EE@amacapital.net> <6F1FD9DA-5E86-42A2-8EAF-05F5D70FE2EF@vmware.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180223 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > > > > Another example is __BPF_PROG_RUN_ARRAY(), which also uses > > preempt_enable_no_resched(). > > Alexei, I think this code is just wrong. why 'just wrong' ? > Do you know why it uses > preempt_enable_no_resched()? dont recall precisely. we could be preemptable at the point where macro is called. I think the goal of no_resched was to avoid adding scheduling points where they didn't exist before just because a prog ran for few nsec. May be Daniel or Roman remember.