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bh=ycwlWjK1cUtfsnTr97lPHy9bLPf8Ff9LLKdvYqykvYY=; b=wrVZ974+jz3x9up+alNPyiIjnC /mJl9S5EGt1onTqEAMLEkfVTGcUReagyOF7Fxa00dRA6VNKXaWUmuNFVLLjlH065mfkxeCGbhxj6f qbph7Q2EEYFIq/Z5PDa/qz1MPY5Vy1hBhg59E9PVg0hSNTDpNM+LXXcphUmutABTWlnDKvYPF5YHG N/RjybPLqB4DSBLv6OjmreTOlrDpSbfVi9dyoG/+41VeslScSk6LlRcsnm2lRO1ICz62FmgIDPYmP XAH3GT6hG0FrQD+dv8yjs8lp25EombKb7KRoqdfZtOryWHvRQO2GZaeNShKRUJJYMG0pGk+Zl7pjh FEO+ZmTA==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.96 #2 (Red Hat Linux)) id 1pef1R-00D6NS-0E; Tue, 21 Mar 2023 16:39:41 +0000 Date: Tue, 21 Mar 2023 09:39:41 -0700 From: Luis Chamberlain To: Christian Brauner Cc: Yangtao Li , Alexander Viro , Andrew Morton , Kees Cook , Iurii Zaikin , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] fs/drop_caches: move drop_caches sysctls into its own file Message-ID: References: <20230321130908.6972-1-frank.li@vivo.com> <20230321142836.l6pymt4ygg2qhfvn@wittgenstein> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230321142836.l6pymt4ygg2qhfvn@wittgenstein> X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: 6o3mnyzndhsx1dkoxu4otmug8cbaekhn X-Rspamd-Queue-Id: E4F434001D X-HE-Tag: 1679416791-166703 X-HE-Meta: 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 /AzMwQzD iJZkB4PxnbEMDVKYSzrSMntJ/0U+cjSXT3UMKRDAvW6ZyWQvOA30OxoK8AjVilGt5woZrO0aZfazNFq3/LDUhtCtbpXdKXxFzWUWnJiC+AE2reMLXq/X8sSIT/0f2SjpqKqi5ENTzSsFbaNOOs1k3MFy0BbmgJJDok/Dyc09a08PlC2meF2Od0WtnpTODRsRLT9NbsfmZ6R+NiRsVS/m2DyoNRdypEQLrUrWru+/Rel3QiPncv8ErctQZDNnHxBMzYBl/1Bj46UV8rCHGI9LjVu1w8mqKU64TgSxa0HWj6StFmmb4PKeheAn/95LTmm4PrMaxdrU4g9QIcPln6VWc5MD6r79kByyXhKarBN3EXQBB3sYgjOCoDPCuiYgfVN308YZEepPBKN02BaOffhmQxyWhTPbUPsbqM2uwDi9CyY4Auy4= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Mar 21, 2023 at 03:28:36PM +0100, Christian Brauner wrote: > On Tue, Mar 21, 2023 at 09:09:07PM +0800, Yangtao Li wrote: > > This moves the fs/drop_caches.c respective sysctls to its own file. > > > > Signed-off-by: Yangtao Li > > --- > > fs/drop_caches.c | 25 ++++++++++++++++++++++--- > > include/linux/mm.h | 6 ------ > > kernel/sysctl.c | 9 --------- > > 3 files changed, 22 insertions(+), 18 deletions(-) > > > > diff --git a/fs/drop_caches.c b/fs/drop_caches.c > > index e619c31b6bd9..3032b83ce6f2 100644 > > --- a/fs/drop_caches.c > > +++ b/fs/drop_caches.c > > @@ -12,8 +12,7 @@ > > #include > > #include "internal.h" > > > > -/* A global variable is a bit ugly, but it keeps the code simple */ > > -int sysctl_drop_caches; > > +static int sysctl_drop_caches; > > > > static void drop_pagecache_sb(struct super_block *sb, void *unused) > > { > > @@ -47,7 +46,7 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused) > > iput(toput_inode); > > } > > > > -int drop_caches_sysctl_handler(struct ctl_table *table, int write, > > +static int drop_caches_sysctl_handler(struct ctl_table *table, int write, > > void *buffer, size_t *length, loff_t *ppos) > > { > > int ret; > > @@ -75,3 +74,23 @@ int drop_caches_sysctl_handler(struct ctl_table *table, int write, > > } > > return 0; > > } > > + > > +static struct ctl_table drop_caches_table[] = { > > + { > > + .procname = "drop_caches", > > + .data = &sysctl_drop_caches, > > + .maxlen = sizeof(int), > > + .mode = 0200, > > + .proc_handler = drop_caches_sysctl_handler, > > + .extra1 = SYSCTL_ONE, > > + .extra2 = SYSCTL_FOUR, > > + }, > > + {} > > +}; > > + > > +static int __init drop_cache_init(void) > > +{ > > + register_sysctl_init("vm", drop_caches_table); > > Does this belong under mm/ or fs/? To not break old userspace it must be kept under "vm" because the patch author is moving it from the kernel/sysctl.c table which used the "vm" table. Moving it to "fs" would be a highly functional change which should require review from maintainers it would not break existing userspace expecations. > And is it intended to be moved into a completely separate file? What do you mean by this? > Feels abit wasteful for 20 lines of code... Not sure what you mean by this either. The commit log sucks, please review got log kernel/sysclt.c for much better commit logs for the rationale of moving sysctls out out kernel/sysctl.c to their own respective places. Luis