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Message-Id: <1586342714-12536-39-git-send-email-wangshilong1991@gmail.com>
Date: Wed, 8 Apr 2020 19:45:06 +0900
From: Wang Shilong <wangshilong1991@...il.com>
To: linux-ext4@...r.kernel.org
Cc: lixi@....com, adilger@...ger.ca, sihara@....com,
Wang Shilong <wshilong@....com>
Subject: [RFC PATCH 38/46] e2fsck: fix readahead for pfsck of pass1
From: Wang Shilong <wshilong@....com>
Several improvments for this patch:
1) move readahead_kb detection to preparing phase.
2) inode readahead should be aware of thread block group
boundary.
3) make readahead_kb aware of multiple threads.
Signed-off-by: Wang Shilong <wshilong@....com>
---
e2fsck/pass1.c | 89 +++++++++++++++++++++++++++++++-------------------
1 file changed, 55 insertions(+), 34 deletions(-)
diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index 4654e673..efd2e72d 100644
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -1173,13 +1173,14 @@ static void pass1_readahead(e2fsck_t ctx, dgrp_t *group, ext2_ino_t *next_ino)
dgrp_t start = *group, grp;
blk64_t blocks_to_read = 0;
errcode_t err = EXT2_ET_INVALID_ARGUMENT;
+ dgrp_t grp_end = ctx->thread_info.et_group_end;
if (ctx->readahead_kb == 0)
goto out;
/* Keep iterating groups until we have enough to readahead */
inodes_per_block = EXT2_INODES_PER_BLOCK(ctx->fs->super);
- for (grp = start; grp < ctx->fs->group_desc_count; grp++) {
+ for (grp = start; grp < grp_end; grp++) {
if (ext2fs_bg_flags_test(ctx->fs, grp, EXT2_BG_INODE_UNINIT))
continue;
inodes_in_group = ctx->fs->super->s_inodes_per_group -
@@ -1271,6 +1272,38 @@ static int e2fsck_should_abort(e2fsck_t ctx)
return 0;
}
+/**
+ * Even though we could specify number of threads,
+ * but it might be more than the whole filesystem
+ * block groups, correct it here.
+ */
+static void e2fsck_pass1_set_thread_num(e2fsck_t ctx)
+{
+ unsigned flexbg_size = 1;
+ ext2_filsys fs = ctx->fs;
+ int num_threads = ctx->fs_num_threads;
+ int max_threads;
+
+ if (num_threads < 1)
+ num_threads = 1;
+
+ if (ext2fs_has_feature_flex_bg(fs->super))
+ flexbg_size = 1 << fs->super->s_log_groups_per_flex;
+
+ max_threads = fs->group_desc_count / flexbg_size;
+ if (max_threads == 0)
+ num_threads = 1;
+ else if (max_threads % num_threads) {
+ int times = max_threads / num_threads;
+
+ if (times == 0)
+ num_threads = max_threads;
+ else
+ num_threads = max_threads / times;
+ }
+ ctx->fs_num_threads = num_threads;
+}
+
/*
* We need call mark_table_blocks() before multiple
* thread start, since all known system blocks should be
@@ -1280,6 +1313,20 @@ static int _e2fsck_pass1_prepare(e2fsck_t ctx)
{
struct problem_context pctx;
ext2_filsys fs = ctx->fs;
+ unsigned long long readahead_kb;
+
+ e2fsck_pass1_set_thread_num(ctx);
+ /* If we can do readahead, figure out how many groups to pull in. */
+ if (!e2fsck_can_readahead(ctx->fs))
+ ctx->readahead_kb = 0;
+ else if (ctx->readahead_kb == ~0ULL)
+ ctx->readahead_kb = e2fsck_guess_readahead(ctx->fs);
+
+ /* don't use more than 1/10 of memory for threads checking */
+ readahead_kb = get_memory_size() / (10 * ctx->fs_num_threads);
+ /* maybe better disable RA if this is too small? */
+ if (ctx->readahead_kb > readahead_kb)
+ ctx->readahead_kb = readahead_kb;
clear_problem_context(&pctx);
if (!(ctx->options & E2F_OPT_PREEN))
@@ -1460,13 +1507,7 @@ void _e2fsck_pass1(e2fsck_t ctx)
init_resource_track(&rtrack, ctx->fs->io);
clear_problem_context(&pctx);
- /* If we can do readahead, figure out how many groups to pull in. */
- if (!e2fsck_can_readahead(ctx->fs))
- ctx->readahead_kb = 0;
- else if (ctx->readahead_kb == ~0ULL)
- ctx->readahead_kb = e2fsck_guess_readahead(ctx->fs);
pass1_readahead(ctx, &ra_group, &ino_threshold);
-
if (ext2fs_has_feature_dir_index(fs->super) &&
!(ctx->options & E2F_OPT_NO)) {
if (ext2fs_u32_list_create(&ctx->dirs_to_hash, 50))
@@ -2993,7 +3034,7 @@ static int e2fsck_pass1_thread_join(e2fsck_t global_ctx, e2fsck_t thread_ctx)
}
static int e2fsck_pass1_threads_join(struct e2fsck_thread_info *infos,
- int num_threads, e2fsck_t global_ctx)
+ e2fsck_t global_ctx)
{
errcode_t rc;
errcode_t ret = 0;
@@ -3002,7 +3043,7 @@ static int e2fsck_pass1_threads_join(struct e2fsck_thread_info *infos,
/* merge invalid bitmaps will recalculate it */
global_ctx->invalid_bitmaps = 0;
- for (i = 0; i < num_threads; i++) {
+ for (i = 0; i < global_ctx->fs_num_threads; i++) {
pinfo = &infos[i];
if (!pinfo->eti_started)
@@ -3079,7 +3120,7 @@ out:
}
static int e2fsck_pass1_threads_start(struct e2fsck_thread_info **pinfo,
- int num_threads, e2fsck_t global_ctx)
+ e2fsck_t global_ctx)
{
struct e2fsck_thread_info *infos;
pthread_attr_t attr;
@@ -3094,6 +3135,7 @@ static int e2fsck_pass1_threads_start(struct e2fsck_thread_info **pinfo,
thread_debug.etd_finished_threads = 0;
#endif
+ int num_threads = global_ctx->fs_num_threads;
retval = pthread_attr_init(&attr);
if (retval) {
@@ -3148,7 +3190,7 @@ static int e2fsck_pass1_threads_start(struct e2fsck_thread_info **pinfo,
}
if (retval) {
- e2fsck_pass1_threads_join(infos, num_threads, global_ctx);
+ e2fsck_pass1_threads_join(infos, global_ctx);
return retval;
}
*pinfo = infos;
@@ -3179,13 +3221,7 @@ static void init_ext2_max_sizes()
static void e2fsck_pass1_multithread(e2fsck_t global_ctx)
{
struct e2fsck_thread_info *infos = NULL;
- int num_threads = global_ctx->fs_num_threads;
errcode_t retval;
- unsigned flexbg_size = 1;
- int max_threads;
-
- if (num_threads < 1)
- num_threads = 1;
retval = _e2fsck_pass1_prepare(global_ctx);
if (retval)
@@ -3194,31 +3230,16 @@ static void e2fsck_pass1_multithread(e2fsck_t global_ctx)
pthread_mutex_init(&global_ctx->fs_fix_mutex, NULL);
pthread_mutex_init(&global_ctx->fs_block_map_mutex, NULL);
pthread_mutex_init(&global_ctx->fs_ea_mutex, NULL);
- if (ext2fs_has_feature_flex_bg(global_ctx->fs->super))
- flexbg_size = 1 << global_ctx->fs->super->s_log_groups_per_flex;
-
- max_threads = global_ctx->fs->group_desc_count / flexbg_size;
- if (max_threads == 0)
- num_threads = 1;
- else if (max_threads % num_threads) {
- int times = max_threads / num_threads;
-
- if (times == 0)
- num_threads = max_threads;
- else
- num_threads = max_threads / times;
- }
- global_ctx->fs_num_threads = num_threads;
init_ext2_max_sizes();
- retval = e2fsck_pass1_threads_start(&infos, num_threads, global_ctx);
+ retval = e2fsck_pass1_threads_start(&infos, global_ctx);
if (retval) {
com_err(global_ctx->program_name, retval,
_("while starting pass1 threads\n"));
goto out_abort;
}
- retval = e2fsck_pass1_threads_join(infos, num_threads, global_ctx);
+ retval = e2fsck_pass1_threads_join(infos, global_ctx);
if (retval) {
com_err(global_ctx->program_name, retval,
_("while joining pass1 threads\n"));
--
2.25.2
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