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vm-monitor: Remove support for file cache in tmpfs (#5617)

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ref neondatabase/cloud#7516.

We switched everything over to file cache on disk, now time to remove
support for having it in tmpfs.
This commit is contained in:
Em Sharnoff
2023-11-02 09:06:16 -07:00
committed by GitHub
parent 51570114ea
commit 367971a0e9
4 changed files with 15 additions and 58 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
compute_tools/src/bin/compute_ctl.rs
View File

@@ -283,7 +283,6 @@ fn main() -> Result<()> {
.expect("--vm-monitor-addr should always be set because it has a default arg");
let file_cache_connstr = matches.get_one::<String>("filecache-connstr");
let cgroup = matches.get_one::<String>("cgroup");
let file_cache_on_disk = matches.get_flag("file-cache-on-disk");
// Only make a runtime if we need to.
// Note: it seems like you can make a runtime in an inner scope and
@@ -310,7 +309,6 @@ fn main() -> Result<()> {
cgroup: cgroup.cloned(),
pgconnstr: file_cache_connstr.cloned(),
addr: vm_monitor_addr.clone(),
file_cache_on_disk,
})),
token.clone(),
))
@@ -482,6 +480,8 @@ fn cli() -> clap::Command {
.value_name("FILECACHE_CONNSTR"),
)
.arg(
// DEPRECATED, NO LONGER DOES ANYTHING.
// See https://github.com/neondatabase/cloud/issues/7516
Arg::new("file-cache-on-disk")
.long("file-cache-on-disk")
.action(clap::ArgAction::SetTrue),

24
libs/vm_monitor/src/filecache.rs
View File

@@ -21,11 +21,6 @@ pub struct FileCacheState {
#[derive(Debug)]
pub struct FileCacheConfig {
/// Whether the file cache is *actually* stored in memory (e.g. by writing to
/// a tmpfs or shmem file). If true, the size of the file cache will be counted against the
/// memory available for the cgroup.
pub(crate) in_memory: bool,
/// The size of the file cache, in terms of the size of the resource it consumes
/// (currently: only memory)
///
@@ -59,22 +54,9 @@ pub struct FileCacheConfig {
spread_factor: f64,
}
impl FileCacheConfig {
pub fn default_in_memory() -> Self {
impl Default for FileCacheConfig {
fn default() -> Self {
Self {
in_memory: true,
// 75 %
resource_multiplier: 0.75,
// 640 MiB; (512 + 128)
min_remaining_after_cache: NonZeroU64::new(640 * MiB).unwrap(),
// ensure any increase in file cache size is split 90-10 with 10% to other memory
spread_factor: 0.1,
}
}
pub fn default_on_disk() -> Self {
Self {
in_memory: false,
resource_multiplier: 0.75,
// 256 MiB - lower than when in memory because overcommitting is safe; if we don't have
// memory, the kernel will just evict from its page cache, rather than e.g. killing
@@ -83,7 +65,9 @@ impl FileCacheConfig {
spread_factor: 0.1,
}
}
}
impl FileCacheConfig {
/// Make sure fields of the config are consistent.
pub fn validate(&self) -> anyhow::Result<()> {
// Single field validity

10
libs/vm_monitor/src/lib.rs
View File

@@ -39,16 +39,6 @@ pub struct Args {
#[arg(short, long)]
pub pgconnstr: Option<String>,
/// Flag to signal that the Postgres file cache is on disk (i.e. not in memory aside from the
/// kernel's page cache), and therefore should not count against available memory.
//
// NB: Ideally this flag would directly refer to whether the file cache is in memory (rather
// than a roundabout way, via whether it's on disk), but in order to be backwards compatible
// during the switch away from an in-memory file cache, we had to default to the previous
// behavior.
#[arg(long)]
pub file_cache_on_disk: bool,
/// The address we should listen on for connection requests. For the
/// agent, this is 0.0.0.0:10301. For the informant, this is 127.0.0.1:10369.
#[arg(short, long)]

35
libs/vm_monitor/src/runner.rs
View File

@@ -156,10 +156,7 @@ impl Runner {
// memory limits.
if let Some(connstr) = &args.pgconnstr {
info!("initializing file cache");
let config = match args.file_cache_on_disk {
true => FileCacheConfig::default_on_disk(),
false => FileCacheConfig::default_in_memory(),
};
let config = FileCacheConfig::default();
let mut file_cache = FileCacheState::new(connstr, config, token.clone())
.await
@@ -187,10 +184,7 @@ impl Runner {
info!("file cache size actually got set to {actual_size}")
}
if args.file_cache_on_disk {
file_cache_disk_size = actual_size;
}
file_cache_disk_size = actual_size;
state.filecache = Some(file_cache);
}
@@ -239,17 +233,11 @@ impl Runner {
let requested_mem = target.mem;
let usable_system_memory = requested_mem.saturating_sub(self.config.sys_buffer_bytes);
let (expected_file_cache_size, expected_file_cache_disk_size) = self
let expected_file_cache_size = self
.filecache
.as_ref()
.map(|file_cache| {
let size = file_cache.config.calculate_cache_size(usable_system_memory);
match file_cache.config.in_memory {
true => (size, 0),
false => (size, size),
}
})
.unwrap_or((0, 0));
.map(|file_cache| file_cache.config.calculate_cache_size(usable_system_memory))
.unwrap_or(0);
if let Some(cgroup) = &self.cgroup {
let (last_time, last_history) = *cgroup.watcher.borrow();
@@ -273,7 +261,7 @@ impl Runner {
let new_threshold = self
.config
.cgroup_threshold(usable_system_memory, expected_file_cache_disk_size);
.cgroup_threshold(usable_system_memory, expected_file_cache_size);
let current = last_history.avg_non_reclaimable;
@@ -300,13 +288,10 @@ impl Runner {
.set_file_cache_size(expected_file_cache_size)
.await
.context("failed to set file cache size")?;
if !file_cache.config.in_memory {
file_cache_disk_size = actual_usage;
}
file_cache_disk_size = actual_usage;
let message = format!(
"set file cache size to {} MiB (in memory = {})",
"set file cache size to {} MiB",
bytes_to_mebibytes(actual_usage),
file_cache.config.in_memory,
);
info!("downscale: {message}");
status.push(message);
@@ -357,9 +342,7 @@ impl Runner {
.set_file_cache_size(expected_usage)
.await
.context("failed to set file cache size")?;
if !file_cache.config.in_memory {
file_cache_disk_size = actual_usage;
}
file_cache_disk_size = actual_usage;
if actual_usage != expected_usage {
warn!(