lvm2/0040-writecache-check-memory-usage.patch

102 lines
2.9 KiB
Diff

From 10a598075a0fdf6d93cc2fefa73fc4a5f1d0de48 Mon Sep 17 00:00:00 2001
From: David Teigland <teigland@redhat.com>
Date: Tue, 1 Mar 2022 14:31:39 -0600
Subject: [PATCH 40/54] writecache: check memory usage
warn if writecache neds > 50% of system memory, and
confirm if writecache needs > 90% of system memory.
---
tools/lvconvert.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 69 insertions(+)
diff --git a/tools/lvconvert.c b/tools/lvconvert.c
index 34b82ea02..a90946173 100644
--- a/tools/lvconvert.c
+++ b/tools/lvconvert.c
@@ -6072,6 +6072,69 @@ bad:
return 0;
}
+static int _check_writecache_memory(struct cmd_context *cmd, struct logical_volume *lv_fast,
+ uint32_t block_size_sectors)
+{
+ char line[128];
+ FILE *fp;
+ uint64_t cachevol_size_bytes = lv_fast->size * SECTOR_SIZE;
+ uint64_t need_mem_bytes = 0;
+ uint64_t proc_mem_bytes = 0;
+ uint64_t need_mem_gb;
+ uint64_t proc_mem_gb;
+ unsigned long long proc_mem_kb = 0;
+
+ if (!(fp = fopen("/proc/meminfo", "r")))
+ goto skip_proc;
+
+ while (fgets(line, sizeof(line), fp)) {
+ if (strncmp(line, "MemTotal:", 9))
+ continue;
+ if (sscanf(line, "%*s%llu%*s", &proc_mem_kb) != 1)
+ break;
+ break;
+ }
+ (void)fclose(fp);
+
+ proc_mem_bytes = proc_mem_kb * 1024;
+
+ skip_proc:
+ /* dm-writecache memory consumption per block is 88 bytes */
+ if (block_size_sectors == 8) {
+ need_mem_bytes = cachevol_size_bytes * 88 / 4096;
+ } else if (block_size_sectors == 1) {
+ need_mem_bytes = cachevol_size_bytes * 88 / 512;
+ } else {
+ /* shouldn't happen */
+ log_warn("Unknown memory usage for unknown writecache block_size_sectors %u", block_size_sectors);
+ return 1;
+ }
+
+ need_mem_gb = need_mem_bytes / 1073741824;
+ proc_mem_gb = proc_mem_bytes / 1073741824;
+
+ /*
+ * warn if writecache needs > 50% of main memory, and
+ * confirm if writecache needs > 90% of main memory.
+ */
+ if (need_mem_bytes >= (proc_mem_bytes / 2)) {
+ log_warn("WARNING: writecache size %s will use %llu GiB of system memory (%llu GiB).",
+ display_size(cmd, lv_fast->size),
+ (unsigned long long)need_mem_gb,
+ (unsigned long long)proc_mem_gb);
+
+ if (need_mem_gb >= (proc_mem_gb * 9 / 10)) {
+ if (!arg_is_set(cmd, yes_ARG) &&
+ yes_no_prompt("Continue adding writecache? [y/n]: ") == 'n') {
+ log_error("Conversion aborted.");
+ return 0;
+ }
+ }
+ }
+
+ return 1;
+}
+
int lvconvert_writecache_attach_single(struct cmd_context *cmd,
struct logical_volume *lv,
struct processing_handle *handle)
@@ -6160,6 +6223,12 @@ int lvconvert_writecache_attach_single(struct cmd_context *cmd,
goto_bad;
}
+ if (!_check_writecache_memory(cmd, lv_fast, block_size_sectors)) {
+ if (!is_active && !deactivate_lv(cmd, lv))
+ stack;
+ goto_bad;
+ }
+
if (!is_active) {
if (!deactivate_lv(cmd, lv)) {
log_error("Failed to deactivate LV after checking block size %s", display_lvname(lv));
--
2.34.3