From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-119.freemail.mail.aliyun.com (out30-119.freemail.mail.aliyun.com [115.124.30.119]) (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 C969F22579E for ; Thu, 14 May 2026 02:36:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.119 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778726201; cv=none; b=ABgFwL19ZtMm5Fc1AmSOZdnxE0lqIZ67SXjKsb2NUcTsMACbpSUVQwUspXCOytAn/TALV/sCzE0x7lL/8S1568FL+9xzFkQM30G5jnNYqPWEdgiMqZsjKz/UKsYs7RbpnDBfwisNqngK5PyJaPPgMoyHe6/CUtae5/HEfcAlRzU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778726201; c=relaxed/simple; bh=4hD3+mGVNKit7nmqL1aUiP3qHih+dzLbcePj+87cnM4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=LbWuHT3gpLgsM1bh2DUmLJ8flw6JddD+fFZG0oINX1niaTHPFvsyuLSE3XOfrlN19VTDJxoGCuIGm8sGxtzFE516UHyR+0tlERTKDe/YTV07k3My/M//PaJdMWVfAag9OEMXVN6/2dVlyso7zKjX01nXf3F1i6SkhxFBXhxdl+c= 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=GJKY6KwT; arc=none smtp.client-ip=115.124.30.119 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="GJKY6KwT" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1778726196; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=9pZEled4JvLYVk4shjV5jBHeZWtGWhhaTA9+4lMRxCg=; b=GJKY6KwTogA276dOnT9kiFwtDCeYp/TEcKlkQrUwt0oc2qxCctlEbAsuN7uiSBOo2fOykIkGeTulTWeH4H4TmB4m4ZNeHYoiUUXuEjx7KBUtC/Z7uQPozpW1mXw+u1jmwNRA/0x/xq2ZfdnwCJ+hbxvuMyZH4xjZHujQQFdBY6E= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R731e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033037026112;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=8;SR=0;TI=SMTPD_---0X2vK2P5_1778726195; Received: from 30.74.144.136(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0X2vK2P5_1778726195 cluster:ay36) by smtp.aliyun-inc.com; Thu, 14 May 2026 10:36:35 +0800 Message-ID: <6d6b1949-fb11-4b05-a01a-9427019b3ae0@linux.alibaba.com> Date: Thu, 14 May 2026 10:36:34 +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 1/2] mm: huge_memory: refactor thpsize_shmem_enabled_store() with sysfs_match_string() To: ranxiaokai627@163.com, hughd@google.com, akpm@linux-foundation.org Cc: leitao@debian.org, ljs@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ran.xiaokai@zte.com.cn References: <20260513094508.50888-1-ranxiaokai627@163.com> From: Baolin Wang In-Reply-To: <20260513094508.50888-1-ranxiaokai627@163.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit The subject line should be: "mm: shmem: xxx" On 5/13/26 5:45 PM, ranxiaokai627@163.com wrote: > From: Ran Xiaokai > > Inspired by commit 82d9ff648c6c ("mm: huge_memory: refactor > anon_enabled_store() with set_anon_enabled_mode()"), refactor > thpsize_shmem_enabled_store() using sysfs_match_string(). > This eliminates the duplicated spin_lock/unlock(), set/clear_bit(), > calls across all branches, reducing code duplication. > > Tested with selftests ./run_kselftest.sh -t mm:ksft_thp.sh, > all test cases passed. > > Signed-off-by: Ran Xiaokai > --- You should document your changes under the '---' for the new version, or ideally, include a cover letter describing them. I did some togging and works well (some nits as below). Feel free to add: Reviewed-by: Baolin Wang Tested-by: Baolin Wang > mm/shmem.c | 94 +++++++++++++++++++++++++++++------------------------- > 1 file changed, 51 insertions(+), 43 deletions(-) > > diff --git a/mm/shmem.c b/mm/shmem.c > index 3b5dc21b323c..60cb10854f11 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -5526,6 +5526,29 @@ static ssize_t shmem_enabled_store(struct kobject *kobj, > struct kobj_attribute shmem_enabled_attr = __ATTR_RW(shmem_enabled); > static DEFINE_SPINLOCK(huge_shmem_orders_lock); > > +enum huge_shmem_enabled_mode { > + HUGE_SHMEM_ENABLED_ALWAYS = 0, > + HUGE_SHMEM_ENABLED_INHERIT, > + HUGE_SHMEM_ENABLED_WITHIN_SIZE, > + HUGE_SHMEM_ENABLED_ADVISE, > + HUGE_SHMEM_ENABLED_NEVER, > +}; > + > +static const char * const huge_shmem_enabled_mode_strings[] = { > + [HUGE_SHMEM_ENABLED_ALWAYS] = "always", > + [HUGE_SHMEM_ENABLED_INHERIT] = "inherit", > + [HUGE_SHMEM_ENABLED_WITHIN_SIZE] = "within_size", > + [HUGE_SHMEM_ENABLED_ADVISE] = "advise", > + [HUGE_SHMEM_ENABLED_NEVER] = "never", > +}; > + > +static unsigned long * const huge_shmem_orders_by_mode[] = { > + [HUGE_SHMEM_ENABLED_ALWAYS] = &huge_shmem_orders_always, > + [HUGE_SHMEM_ENABLED_INHERIT] = &huge_shmem_orders_inherit, > + [HUGE_SHMEM_ENABLED_WITHIN_SIZE] = &huge_shmem_orders_within_size, > + [HUGE_SHMEM_ENABLED_ADVISE] = &huge_shmem_orders_madvise, > +}; > + > static ssize_t thpsize_shmem_enabled_show(struct kobject *kobj, > struct kobj_attribute *attr, char *buf) > { > @@ -5551,57 +5574,42 @@ static ssize_t thpsize_shmem_enabled_store(struct kobject *kobj, > const char *buf, size_t count) > { > int order = to_thpsize(kobj)->order; > + int mode, m; > ssize_t ret = count; > + int err; > + bool changed = false; > > - if (sysfs_streq(buf, "always")) { > - spin_lock(&huge_shmem_orders_lock); > - clear_bit(order, &huge_shmem_orders_inherit); > - clear_bit(order, &huge_shmem_orders_madvise); > - clear_bit(order, &huge_shmem_orders_within_size); > - set_bit(order, &huge_shmem_orders_always); > - spin_unlock(&huge_shmem_orders_lock); > - } else if (sysfs_streq(buf, "inherit")) { > - /* Do not override huge allocation policy with non-PMD sized mTHP */ > - if (shmem_huge == SHMEM_HUGE_FORCE && !is_pmd_order(order)) > - return -EINVAL; > + mode = sysfs_match_string(huge_shmem_enabled_mode_strings, buf); > + if (mode < 0) > + return -EINVAL; > > - spin_lock(&huge_shmem_orders_lock); > - clear_bit(order, &huge_shmem_orders_always); > - clear_bit(order, &huge_shmem_orders_madvise); > - clear_bit(order, &huge_shmem_orders_within_size); > - set_bit(order, &huge_shmem_orders_inherit); > - spin_unlock(&huge_shmem_orders_lock); > - } else if (sysfs_streq(buf, "within_size")) { > - spin_lock(&huge_shmem_orders_lock); > - clear_bit(order, &huge_shmem_orders_always); > - clear_bit(order, &huge_shmem_orders_inherit); > - clear_bit(order, &huge_shmem_orders_madvise); > - set_bit(order, &huge_shmem_orders_within_size); > - spin_unlock(&huge_shmem_orders_lock); > - } else if (sysfs_streq(buf, "advise")) { > - spin_lock(&huge_shmem_orders_lock); > - clear_bit(order, &huge_shmem_orders_always); > - clear_bit(order, &huge_shmem_orders_inherit); > - clear_bit(order, &huge_shmem_orders_within_size); > - set_bit(order, &huge_shmem_orders_madvise); > - spin_unlock(&huge_shmem_orders_lock); > - } else if (sysfs_streq(buf, "never")) { > - spin_lock(&huge_shmem_orders_lock); > - clear_bit(order, &huge_shmem_orders_always); > - clear_bit(order, &huge_shmem_orders_inherit); > - clear_bit(order, &huge_shmem_orders_within_size); > - clear_bit(order, &huge_shmem_orders_madvise); > - spin_unlock(&huge_shmem_orders_lock); > - } else { > - ret = -EINVAL; > - } > + /* Do not override huge allocation policy with non-PMD sized mTHP */ > + if (mode == HUGE_SHMEM_ENABLED_INHERIT && > + shmem_huge == SHMEM_HUGE_FORCE && !is_pmd_order(order)) > + return -EINVAL; > > - if (ret > 0) { > - int err = start_stop_khugepaged(); > + spin_lock(&huge_shmem_orders_lock); > + for (m = 0; m < ARRAY_SIZE(huge_shmem_orders_by_mode); m++) { > + if (m == mode) > + changed |= !__test_and_set_bit(order, huge_shmem_orders_by_mode[m]); > + else > + changed |= __test_and_clear_bit(order, huge_shmem_orders_by_mode[m]); > + } > + spin_unlock(&huge_shmem_orders_lock); > > + if (changed) { > + err = start_stop_khugepaged(); > if (err) > ret = err; Nit: just return err. > + } else { > + /* > + * Recalculate watermarks even when the mode hasn't changed > + * to preserve the legacy behavior, as this is always called > + * inside start_stop_khugepaged(). > + */ > + set_recommended_min_free_kbytes(); > } > + > return ret; Nit: return count, then you can remove the 'ret' variable.