From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f54.google.com (mail-ed1-f54.google.com [209.85.208.54]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D7BED349B1D for ; Wed, 11 Mar 2026 03:12:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.54 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773198754; cv=none; b=kVK6LbMKo9hpWso68Xn2rI7q5B1Ku9YSgCXQGSfD4N2V9eO9aAC7HlF4z9DsEBXndSRgKOLNJEJa7dr8iLSyVFVykjDlpBFuHmWbrLbcrWPCH0HX4Oww8PvEd7p8pCU0nIZ2e5MQX6pLa9vEf2tYeoVQjJEnwZxxNooGqs9bB+s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773198754; c=relaxed/simple; bh=tf3LYuz23GV0ODxonGl3Y8ZY9JPyaJtxurs8z9qrzx4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ifFfP/Y6k6+brwaDrmxYLPDzD0+InKjBHPpyVWwsjFBZLyYT/eSE3+1rT+4srNd/+/guO4UhNCcjh3EjEWQP0/orNixP1tva986taoK069/pZPvi0kzPEgxKNrBeVg/ZjTXumESAY4QlYvitSKN/q2Uh5dJCkqsPzmocuyiHdY4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=nbBwU95N; arc=none smtp.client-ip=209.85.208.54 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="nbBwU95N" Received: by mail-ed1-f54.google.com with SMTP id 4fb4d7f45d1cf-662b933f8d1so3224165a12.2 for ; Tue, 10 Mar 2026 20:12:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1773198751; x=1773803551; darn=vger.kernel.org; h=user-agent:in-reply-to:content-disposition:mime-version:references :reply-to:message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=vx+itT2HSu3dk1ig1D+Qzvgul/sL04it9W0U5s6U7wM=; b=nbBwU95Nor4oUz4jS5q4D9fSlr3T0BTS0/4a2p3nXQTv4vkuzPOUDmND438roDwAJr G83w7ex55w8dtdPsaRUvfZzn30z0r/SNOy4iGVR7dpZQCgGnZl9ZjvbmWUQPiUR7/OQp xWNm7IrOFBcaKcdSOk631BJuYfd5B/BRVS2Ll4c6a2bUZdTdZLRhKck0eBRl/208Qjz6 CsqC7Dtpd6ZPLOU6oICpgXCp3SZM6BEFPdyJjHGUvCeCxFvrI6zvg5oVxH60jx8bjTHa w70iE+1EZd8cWcJK5n2EfVClAV5ho3QOIyGqpHH0UcbfXTQUF9284ESbxW8TjswVnHZO +suw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1773198751; x=1773803551; h=user-agent:in-reply-to:content-disposition:mime-version:references :reply-to:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=vx+itT2HSu3dk1ig1D+Qzvgul/sL04it9W0U5s6U7wM=; b=IQtpHA+Idx7duMdI/wBxsqIXzj2Xr4GYOMknMRKr6C+2uINbgwGbCyizyyzCzfmWux jHfLVmTBGXVQSluDah/mEeEBWVkDfd+7RW3VbNGsNaEAWlvDzvG1ZOFDbmsdSb6ReIi5 W2V0JDA+Pm92/NfgareP0XG/Kc66vLiA+DUyXWcbnqfCmNemmJr125PXNWrHKs1F7W1w 0x/igZDL3PAhtV8eRPijdsJnxnUtmdEqLTLpVlkVZmHS4b4HtDPwVjJUp3ndmh8bAAAb 0gq6iJzAdR3HVYSimlqSaUgHqkKXSm4sbrXrahoJFnKS7dM0JKMPW75KIxPSlg82wgqC loaw== X-Forwarded-Encrypted: i=1; AJvYcCXTLeR7JrJzQKMJQUQP+3RXYFL8jpUcI6TATPsJLK5Vpv5KCnjGGFZRHyA6NFxUTBJS+TUV+c8lbB8RIGQ=@vger.kernel.org X-Gm-Message-State: AOJu0YxOsPxm02N/bWlGAuWOwD0x1VR2m6hE34L4kgaeO+T0dYWTC8j+ eDQmh32JDoWBl/sMYk4Kk3EeXBRNAGgGEKTLQKOavrl0UtBE+5VLAejt X-Gm-Gg: ATEYQzz+76YCXLrAhQvCfFS3SUQhG5T467r7OBFUx+XY7K7kh9Al9ArbabS0qlBGpzJ Te00Sknsec3kx4y+7ASAuozTuUpEcEFm0dVtiUzOJAx0g0H24zEzuW8p2aSVwRp/t7IVzEJLbQY +48W0I6lk5plp0ewuIlKbdPO/nSoKqckT9ewpUkbV5NXOTe5c5DQmhmoT4mAu251Ju6/e/i/u80 idq+jbgDu++zEcq2ajrUCpsPH68Ln9HyS5KkrtNRQlYy+hRpNl3NC8Hfk3LIP4TDqOMU3LJVpJ+ zcC9F8d5pTPAsU5HtmKuu8I9UbA3k0wAKYz0vSIxwj+DCbG3j87X1oMfPwDD6ghJjhIeHlsOo95 vdFvWdQzbbxj06AvN0GghdGSBDr3toRqZvCnD7+8wnfUR+2t37fwIzQ0Joub/stJcUy7C55ESTx 1ohhf8xg64Xl0HqkY784F0Bw== X-Received: by 2002:a05:6402:13d6:b0:65c:354e:94f0 with SMTP id 4fb4d7f45d1cf-663198c39bamr417662a12.8.1773198750894; Tue, 10 Mar 2026 20:12:30 -0700 (PDT) Received: from localhost ([185.92.221.13]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-66315320df2sm239220a12.24.2026.03.10.20.12.30 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Tue, 10 Mar 2026 20:12:30 -0700 (PDT) Date: Wed, 11 Mar 2026 03:12:29 +0000 From: Wei Yang To: Breno Leitao Cc: Andrew Morton , David Hildenbrand , Lorenzo Stoakes , Zi Yan , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Mike Rapoport , linux-mm@kvack.org, linux-kernel@vger.kernel.org, usamaarif642@gmail.com, kas@kernel.org, kernel-team@meta.com, "Lorenzo Stoakes (Oracle)" Subject: Re: [PATCH v5 2/4] mm: huge_memory: refactor anon_enabled_store() with change_anon_orders() Message-ID: <20260311031229.mloqvlmmqipr7k2h@master> Reply-To: Wei Yang References: <20260310-thp_logs-v5-0-686099175bf6@debian.org> <20260310-thp_logs-v5-2-686099175bf6@debian.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260310-thp_logs-v5-2-686099175bf6@debian.org> User-Agent: NeoMutt/20170113 (1.7.2) On Tue, Mar 10, 2026 at 10:57:08AM -0700, 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 anon_enabled_mode and anon_enabled_mode_strings[] >for the per-order anon THP setting. > >Use sysfs_match_string() with the anon_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 >Reviewed-by: Lorenzo Stoakes (Oracle) >--- > 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..e19dda5aaf195 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 anon_enabled_mode { >+ ANON_ENABLED_ALWAYS = 0, >+ ANON_ENABLED_MADVISE = 1, >+ ANON_ENABLED_INHERIT = 2, >+ ANON_ENABLED_NEVER = 3, >+}; >+ >+static const char * const anon_enabled_mode_strings[] = { >+ [ANON_ENABLED_ALWAYS] = "always", >+ [ANON_ENABLED_MADVISE] = "madvise", >+ [ANON_ENABLED_INHERIT] = "inherit", >+ [ANON_ENABLED_NEVER] = "never", >+}; >+ Just one trivial thing, maybe keep the sequence as the sysfs output? Currently the output of /sys/kernel/transparent_hugepage/hugepages-xxxkB is always inherit madvise [never] But no strong opinion on this. > 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 set_anon_enabled_mode(int order, enum anon_enabled_mode mode) >+{ >+ static unsigned long *enabled_orders[] = { >+ &huge_anon_orders_always, >+ &huge_anon_orders_madvise, >+ &huge_anon_orders_inherit, >+ }; >+ enum anon_enabled_mode m; >+ bool changed = false; >+ >+ spin_lock(&huge_anon_orders_lock); >+ for (m = 0; m < ARRAY_SIZE(enabled_orders); m++) { >+ if (m == mode) >+ changed |= !__test_and_set_bit(order, enabled_orders[m]); >+ else >+ changed |= __test_and_clear_bit(order, enabled_orders[m]); >+ } >+ spin_unlock(&huge_anon_orders_lock); >+ >+ return changed; >+} >+ Nice cleanup, so Reviewed-by: Wei Yang > 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(anon_enabled_mode_strings, buf); >+ if (mode < 0) >+ return -EINVAL; > >- if (ret > 0) { >- int err; >+ if (set_anon_enabled_mode(order, mode)) { >+ int err = start_stop_khugepaged(); > >- 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(); > } >- return ret; >+ >+ return count; > } > > static struct kobj_attribute anon_enabled_attr = > >-- >2.52.0 > -- Wei Yang Help you, Help me