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authorAlexey Dobriyan <adobriyan@gmail.com>2018-02-06 15:37:06 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-06 18:32:43 -0800
commit20d28cde5558a2a211620254ec7bc53a4334167f (patch)
treea582f9fb922b27400f251686ab8212825b8a9745 /fs
parent593bc695a1102a540f1613c651e73693b17a7343 (diff)
proc: less memory for /proc/*/map_files readdir
dentry name can be evaluated later, right before calling into VFS. Also, spend less time under ->mmap_sem. Link: http://lkml.kernel.org/r/20171110163034.GA2534@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/proc/base.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 4c12cb2cd704..a3efc2427c74 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2026,9 +2026,9 @@ out:
}
struct map_files_info {
+ unsigned long start;
+ unsigned long end;
fmode_t mode;
- unsigned int len;
- unsigned char name[4*sizeof(long)+2]; /* max: %lx-%lx\0 */
};
/*
@@ -2198,10 +2198,9 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
if (++pos <= ctx->pos)
continue;
+ info.start = vma->vm_start;
+ info.end = vma->vm_end;
info.mode = vma->vm_file->f_mode;
- info.len = snprintf(info.name,
- sizeof(info.name), "%lx-%lx",
- vma->vm_start, vma->vm_end);
if (flex_array_put(fa, i++, &info, GFP_KERNEL))
BUG();
}
@@ -2209,9 +2208,13 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
up_read(&mm->mmap_sem);
for (i = 0; i < nr_files; i++) {
+ char buf[4 * sizeof(long) + 2]; /* max: %lx-%lx\0 */
+ unsigned int len;
+
p = flex_array_get(fa, i);
+ len = snprintf(buf, sizeof(buf), "%lx-%lx", p->start, p->end);
if (!proc_fill_cache(file, ctx,
- p->name, p->len,
+ buf, len,
proc_map_files_instantiate,
task,
(void *)(unsigned long)p->mode))