Messages in this thread |  | | From | Barry Song <> | | Date | Fri, 3 Apr 2026 14:56:38 +0800 | | Subject | Re: [PATCH 2/2] mm: huge_memory: refactor defrag_show() to use defrag_flags[] |
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On Sat, Mar 21, 2026 at 12:06 AM Breno Leitao <leitao@debian.org> wrote: > > Replace the hardcoded if/else chain of test_bit() calls and string > literals in defrag_show() with a loop over defrag_flags[] and > defrag_mode_strings[] arrays introduced in the previous commit. > > This makes defrag_show() consistent with defrag_store() and eliminates > the duplicated mode name strings. > > Signed-off-by: Breno Leitao <leitao@debian.org> > --- > mm/huge_memory.c | 38 ++++++++++++++++++++++---------------- > 1 file changed, 22 insertions(+), 16 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 4843e2154038f..eaa6623fa49e2 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -447,24 +447,30 @@ static const enum transparent_hugepage_flag defrag_flags[] = { > static ssize_t defrag_show(struct kobject *kobj, > struct kobj_attribute *attr, char *buf) > { > - const char *output; > + int active = DEFRAG_NEVER; > + int len = 0; > + int i; > > - if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, > - &transparent_hugepage_flags)) > - output = "[always] defer defer+madvise madvise never"; > - else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, > - &transparent_hugepage_flags)) > - output = "always [defer] defer+madvise madvise never"; > - else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, > - &transparent_hugepage_flags)) > - output = "always defer [defer+madvise] madvise never"; > - else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, > - &transparent_hugepage_flags)) > - output = "always defer defer+madvise [madvise] never"; > - else > - output = "always defer defer+madvise madvise [never]"; > + for (i = 0; i < ARRAY_SIZE(defrag_flags); i++) { > + if (test_bit(defrag_flags[i], &transparent_hugepage_flags)) { > + active = i; > + break; > + } > + } > > - return sysfs_emit(buf, "%s\n", output); > + for (i = 0; i < ARRAY_SIZE(defrag_mode_strings); i++) { > + if (i == active) > + len += sysfs_emit_at(buf, len, "[%s] ", > + defrag_mode_strings[i]); > + else > + len += sysfs_emit_at(buf, len, "%s ", > + defrag_mode_strings[i]); > + } > + > + /* Replace trailing space with newline */ > + buf[len - 1] = '\n'; > +
Interesting. We used to use sysfs_emit(buf, "%s\n", output), which appends a newline automatically. Now you’re replacing the final ' ' with '\n'.
LGTM, Reviewed-by: Barry Song <baohua@kernel.org>
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