LU-17030 llite: allow setting max_cached_mb to a %

[fs/lustre-release.git] / lustre / llite / lproc_llite.c

diff --git a/lustre/llite/lproc_llite.c b/lustre/llite/lproc_llite.c
index 67b47ac..bd4708b 100644 (file)
--- a/lustre/llite/lproc_llite.c
+++ b/lustre/llite/lproc_llite.c
@@ -496,9 +496,11 @@ static ssize_t ll_max_cached_mb_seq_write(struct file *file,
        long diff = 0;
        long nrpages = 0;
        __u16 refcheck;
+       u64 value;
        u64 pages_number;
        int rc;
        char kernbuf[128], *ptr;
+       bool percent = false;
 
        ENTRY;
        if (count >= sizeof(kernbuf))
@@ -506,14 +508,28 @@ static ssize_t ll_max_cached_mb_seq_write(struct file *file,
 
        if (copy_from_user(kernbuf, buffer, count))
                RETURN(-EFAULT);
-       kernbuf[count] = '\0';
+
+       if (count > 0 && kernbuf[count - 1] == '%') {
+               percent = true;
+               /* strip off the % */
+               kernbuf[count - 1] = '\0';
+       } else {
+               kernbuf[count] = '\0';
+       }
 
        ptr = lprocfs_find_named_value(kernbuf, "max_cached_mb:", &count);
-       rc = sysfs_memparse(ptr, count, &pages_number, "MiB");
+       if (percent)
+               rc = sysfs_memparse(ptr, count, &value, "B");
+       else
+               rc = sysfs_memparse(ptr, count, &value, "MiB");
        if (rc)
                RETURN(rc);
 
-       pages_number >>= PAGE_SHIFT;
+       if (percent) {
+               pages_number = cfs_totalram_pages() * value / 100;
+       } else {
+               pages_number = value >> PAGE_SHIFT;
+       }
 
        if (pages_number < 0 || pages_number > cfs_totalram_pages()) {
                CERROR("%s: can't set max cache more than %lu MB\n",