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Sun, 17 Mar 2024 21:34:20 +0000 (GMT) Received: from [10.61.2.107] (haven.au.ibm.com [9.192.254.114]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.au.ibm.com (Postfix) with ESMTPSA id D1499600F0; Mon, 18 Mar 2024 08:34:17 +1100 (AEDT) Message-ID: <175080fd47ff7e016a73a553c1b93d2bc8bdae39.camel@linux.ibm.com> Subject: Re: [PATCH v1 2/2] powerpc/code-patching: Convert to open_patch_window()/close_patch_window() From: Benjamin Gray To: Christophe Leroy , "linuxppc-dev@lists.ozlabs.org" , "mpe@ellerman.id.au" Date: Mon, 18 Mar 2024 08:34:17 +1100 In-Reply-To: <77fdcdeb-4af5-4ad0-a4c6-57bf0762dc65@csgroup.eu> References: <20240315025937.407590-1-bgray@linux.ibm.com> <20240315025937.407590-2-bgray@linux.ibm.com> <510d986a-ce2b-47dc-bf5e-7ba2e72ecf5a@csgroup.eu> <77fdcdeb-4af5-4ad0-a4c6-57bf0762dc65@csgroup.eu> Autocrypt: addr=bgray@linux.ibm.com; prefer-encrypt=mutual; keydata=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 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.50.4 (3.50.4-1.fc39) MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: iqJW86t3ug8XiojsJrOFJk26-1dMmlKC X-Proofpoint-GUID: iqJW86t3ug8XiojsJrOFJk26-1dMmlKC X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.1011,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2024-03-17_12,2024-03-15_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 spamscore=0 adultscore=0 impostorscore=0 mlxlogscore=999 phishscore=0 mlxscore=0 bulkscore=0 suspectscore=0 clxscore=1011 priorityscore=1501 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2403140000 definitions=main-2403170167 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Sat, 2024-03-16 at 10:10 +0000, Christophe Leroy wrote: >=20 >=20 > Le 15/03/2024 =C3=A0 09:38, Christophe Leroy a =C3=A9crit=C2=A0: > >=20 > >=20 > > Le 15/03/2024 =C3=A0 03:59, Benjamin Gray a =C3=A9crit=C2=A0: > > > The existing patching alias page setup and teardown sections can > > > be > > > simplified to make use of the new open_patch_window() > > > abstraction. > > >=20 > > > This eliminates the _mm variants of the helpers, consumers no > > > longer > > > need to check mm_patch_enabled(), and consumers no longer need to > > > worry > > > about synchronization and flushing beyond the changes they make > > > in the > > > patching window. > >=20 > > With this patch, the time needed to activate or de-activate > > function=20 > > tracer is approx 10% longer on powerpc 8xx. >=20 > With the following changes, the performance is restored: >=20 > diff --git a/arch/powerpc/lib/code-patching.c=20 > b/arch/powerpc/lib/code-patching.c > index fd6f8576033a..bc92b85913d8 100644 > --- a/arch/powerpc/lib/code-patching.c > +++ b/arch/powerpc/lib/code-patching.c > @@ -282,13 +282,13 @@ struct patch_window { > =C2=A0=C2=A0 * Interrupts must be disabled for the entire duration of the= =20 > patching. The PIDR > =C2=A0=C2=A0 * is potentially changed during this time. > =C2=A0=C2=A0 */ > -static int open_patch_window(void *addr, struct patch_window *ctx) > +static __always_inline int open_patch_window(void *addr, struct=20 > patch_window *ctx) > =C2=A0 { > =C2=A0=C2=A0 unsigned long pfn =3D get_patch_pfn(addr); >=20 > =C2=A0=C2=A0 lockdep_assert_irqs_disabled(); >=20 > - ctx->text_poke_addr =3D (unsigned=20 > long)__this_cpu_read(cpu_patching_context.addr); > + ctx->text_poke_addr =3D (unsigned=20 > long)__this_cpu_read(cpu_patching_context.addr) & PAGE_MASK; >=20 > =C2=A0=C2=A0 if (!mm_patch_enabled()) { > =C2=A0=C2=A0 ctx->ptep =3D > __this_cpu_read(cpu_patching_context.pte); > @@ -331,7 +331,7 @@ static int open_patch_window(void *addr, struct=20 > patch_window *ctx) > =C2=A0=C2=A0 return 0; > =C2=A0 } >=20 > -static void close_patch_window(struct patch_window *ctx) > +static __always_inline void close_patch_window(struct patch_window > *ctx) > =C2=A0 { > =C2=A0=C2=A0 lockdep_assert_irqs_disabled(); >=20 >=20 Thanks for checking that. I did restore the page mask optimisation in a later patch while still developing, but the 64-bit assembly looked slightly worse for it. I didn't check the 32-bit; no way to benchmark it anyway.