From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-110.freemail.mail.aliyun.com (out30-110.freemail.mail.aliyun.com [115.124.30.110]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B91AC3368B6 for ; Fri, 6 Mar 2026 06:08:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.110 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772777283; cv=none; b=IM0hgOB27QDrtiIGNWu16snjaus7F92/KLfeRVpdj30m4yu29efNho6fGbTigCGjJmkLjZOMwfWVft0swe33mrS4JjytrkHd7Mg47ixWebYBF09ww+GAG+PE6s75Fz7ErCLtME9OGpy1iWdqSe4MIzdfCK9w7o9WRjywMskG3d4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772777283; c=relaxed/simple; bh=k0ahk5bcXKMP58IxuqdPcRSdylZP9mlXmx6B12dH2+0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=HCKPpyG+tmLedhObD+QX85NgZcEj4dJSVyHPyysr8Dvts7H3jFiTiv4DiAQ/FJ7L5ARIUaOdlXrgj7gAGzYCCeOzkI9GgFRuuIPNBKfCt1s7nSr71KYYbPOsGYPxy6fKvuzFBbpsBoYl8J0SG1yfPyvfOaNTDGhG3xUWakTR98A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=JoWWhjx3; arc=none smtp.client-ip=115.124.30.110 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="JoWWhjx3" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1772777273; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=QyUsGtGIS/Bny0j3Jrlu7OIiSZdRmYRZ1aQvboXUosI=; b=JoWWhjx3KASrgoW2DRgTrVRkKM2827r4oZoCZehrp1RpER1Rt20jkwUhOUU0jXFtLKL9gBZATe0gUq9hZZX0zDDQFPJS5BTV9ezhKGrtoqbgSib4oEYnk8KHi9xsWTlTZgKcoeDdIti0W8D2vlgomXWrq98FhRqgtXC7OFXuPl0= Received: from 30.74.144.109(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0X-MLDCR_1772777271 cluster:ay36) by smtp.aliyun-inc.com; Fri, 06 Mar 2026 14:07:52 +0800 Message-ID: <8b238664-4375-413c-a8cc-105d98430362@linux.alibaba.com> Date: Fri, 6 Mar 2026 14:07:50 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/3] mm: huge_memory: refactor anon_enabled_store() with change_anon_orders() To: Breno Leitao , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , Zi Yan , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, usamaarif642@gmail.com, kas@kernel.org, kernel-team@meta.com References: <20260305-thp_logs-v2-0-96b3ad795894@debian.org> <20260305-thp_logs-v2-2-96b3ad795894@debian.org> From: Baolin Wang In-Reply-To: <20260305-thp_logs-v2-2-96b3ad795894@debian.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 3/5/26 10:04 PM, Breno Leitao wrote: > Consolidate the repeated spin_lock/set_bit/clear_bit pattern in > anon_enabled_store() into a new change_anon_orders() helper that > loops over an orders[] array, setting the bit for the selected mode > and clearing the others. > > Introduce enum enabled_mode and enabled_mode_strings[] to be shared > with enabled_store() in a subsequent patch. > > Use sysfs_match_string() with the enabled_mode_strings[] table to > replace the if/else chain of sysfs_streq() calls. > > The helper uses test_and_set_bit()/test_and_clear_bit() to track > whether the state actually changed, so start_stop_khugepaged() is > only called when needed. When the mode is unchanged, > set_recommended_min_free_kbytes() is called directly to preserve > the watermark recalculation behavior of the original code. > > Signed-off-by: Breno Leitao > --- > mm/huge_memory.c | 84 +++++++++++++++++++++++++++++++++++--------------------- > 1 file changed, 52 insertions(+), 32 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 8e2746ea74adf..19619213f54d1 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -316,6 +316,20 @@ static ssize_t enabled_show(struct kobject *kobj, > return sysfs_emit(buf, "%s\n", output); > } > > +enum enabled_mode { > + ENABLED_ALWAYS, > + ENABLED_MADVISE, > + ENABLED_INHERIT, > + ENABLED_NEVER, > +}; > + > +static const char * const enabled_mode_strings[] = { > + [ENABLED_ALWAYS] = "always", > + [ENABLED_MADVISE] = "madvise", > + [ENABLED_INHERIT] = "inherit", > + [ENABLED_NEVER] = "never", > +}; > + > static ssize_t enabled_store(struct kobject *kobj, > struct kobj_attribute *attr, > const char *buf, size_t count) > @@ -515,48 +529,54 @@ static ssize_t anon_enabled_show(struct kobject *kobj, > return sysfs_emit(buf, "%s\n", output); > } > > +static bool change_anon_orders(int order, enum enabled_mode mode) > +{ > + static unsigned long *orders[] = { > + &huge_anon_orders_always, > + &huge_anon_orders_madvise, > + &huge_anon_orders_inherit, > + }; > + bool changed = false; > + int i; > + > + spin_lock(&huge_anon_orders_lock); > + for (i = 0; i < ARRAY_SIZE(orders); i++) { > + if (i == mode) > + changed |= !test_and_set_bit(order, orders[i]); > + else > + changed |= test_and_clear_bit(order, orders[i]); > + } > + spin_unlock(&huge_anon_orders_lock); > + > + return changed; > +} > + > static ssize_t anon_enabled_store(struct kobject *kobj, > struct kobj_attribute *attr, > const char *buf, size_t count) > { > int order = to_thpsize(kobj)->order; > - ssize_t ret = count; > + int mode; > > - if (sysfs_streq(buf, "always")) { > - spin_lock(&huge_anon_orders_lock); > - clear_bit(order, &huge_anon_orders_inherit); > - clear_bit(order, &huge_anon_orders_madvise); > - set_bit(order, &huge_anon_orders_always); > - spin_unlock(&huge_anon_orders_lock); > - } else if (sysfs_streq(buf, "inherit")) { > - spin_lock(&huge_anon_orders_lock); > - clear_bit(order, &huge_anon_orders_always); > - clear_bit(order, &huge_anon_orders_madvise); > - set_bit(order, &huge_anon_orders_inherit); > - spin_unlock(&huge_anon_orders_lock); > - } else if (sysfs_streq(buf, "madvise")) { > - spin_lock(&huge_anon_orders_lock); > - clear_bit(order, &huge_anon_orders_always); > - clear_bit(order, &huge_anon_orders_inherit); > - set_bit(order, &huge_anon_orders_madvise); > - spin_unlock(&huge_anon_orders_lock); > - } else if (sysfs_streq(buf, "never")) { > - spin_lock(&huge_anon_orders_lock); > - clear_bit(order, &huge_anon_orders_always); > - clear_bit(order, &huge_anon_orders_inherit); > - clear_bit(order, &huge_anon_orders_madvise); > - spin_unlock(&huge_anon_orders_lock); > - } else > - ret = -EINVAL; > + mode = sysfs_match_string(enabled_mode_strings, buf); > + if (mode < 0) > + return -EINVAL; > > - if (ret > 0) { > - int err; > + if (change_anon_orders(order, mode)) { > + int err = start_stop_khugepaged(); Thanks for the cleanup, and the code looks better. > > - err = start_stop_khugepaged(); > if (err) > - ret = err; > + return err; > + } else { > + /* > + * Recalculate watermarks even when the mode didn't > + * change, as the previous code always called > + * start_stop_khugepaged() which does this internally. > + */ > + set_recommended_min_free_kbytes(); However, this won’t fix your issue. You will still get lots of warning messages even if no hugepage options are changed.