From: Breno Leitao Date: Wed, 8 Apr 2026 15:47:00 +0000 (-0700) Subject: mm: huge_memory: use sysfs_match_string() in defrag_store() X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=b0f3d00e15e82242d08791fea00807cb01eb1235;p=thirdparty%2Flinux.git mm: huge_memory: use sysfs_match_string() in defrag_store() Patch series "mm: huge_memory: clean up defrag sysfs with shared", v2. Refactor defrag_store() and defrag_show() to use shared data tables instead of duplicated if/else chains. Patch 1 introduces an enum defrag_mode, a defrag_mode_strings[] table, and a defrag_flags[] mapping array, then rewrites defrag_store() to use sysfs_match_string() with a loop over defrag_flags[]. Patch 2 refactors defrag_show() to use the same arrays, replacing its hardcoded if/else chain of test_bit() calls and string literals. This follows the same pattern applied to anon_enabled_store() in commit 522dfb4ba71f ("mm: huge_memory: refactor anon_enabled_store() with change_anon_orders()"). This patch (of 2): Replace the if/else chain of sysfs_streq() calls in defrag_store() with sysfs_match_string() and a defrag_mode_strings[] table. Introduce enum defrag_mode and defrag_flags[] array mapping each mode to its corresponding transparent_hugepage_flag. The store function now loops over defrag_flags[], setting the bit for the selected mode and clearing the others. When mode is DEFRAG_NEVER (index 4), no index in the 4-element defrag_flags[] matches, so all flags are cleared. Note that the enum ordering (always, defer, defer+madvise, madvise, never) differs from the original if/else chain order in defrag_store() (always, defer+madvise, defer, madvise, never). This is intentional to match the display order used by defrag_show(). This is a follow-up cleanup to commit 522dfb4ba71f ("mm: huge_memory: refactor anon_enabled_store() with change_anon_orders()") which applied the same sysfs_match_string() pattern to anon_enabled_store(). Link: https://lore.kernel.org/20260408-thp_defrag-v2-0-bc544c1bde4e@debian.org Link: https://lore.kernel.org/20260408-thp_defrag-v2-1-bc544c1bde4e@debian.org Signed-off-by: Breno Leitao Acked-by: David Hildenbrand (Arm) Tested-by: Lance Yang Reviewed-by: Lance Yang Reviewed-by: Barry Song Reviewed-by: Lorenzo Stoakes Tested-by: Zi Yan Acked-by: Zi Yan Cc: Baolin Wang Cc: Dev Jain Cc: Liam Howlett Cc: Nico Pache Cc: Ryan Roberts Signed-off-by: Andrew Morton --- diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 4586f3ccb133..62e00b21fdf4 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -429,6 +429,29 @@ ssize_t single_hugepage_flag_store(struct kobject *kobj, return count; } +enum defrag_mode { + DEFRAG_ALWAYS = 0, + DEFRAG_DEFER, + DEFRAG_DEFER_MADVISE, + DEFRAG_MADVISE, + DEFRAG_NEVER, +}; + +static const char * const defrag_mode_strings[] = { + [DEFRAG_ALWAYS] = "always", + [DEFRAG_DEFER] = "defer", + [DEFRAG_DEFER_MADVISE] = "defer+madvise", + [DEFRAG_MADVISE] = "madvise", + [DEFRAG_NEVER] = "never", +}; + +static const enum transparent_hugepage_flag defrag_flags[] = { + [DEFRAG_ALWAYS] = TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, + [DEFRAG_DEFER] = TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, + [DEFRAG_DEFER_MADVISE] = TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, + [DEFRAG_MADVISE] = TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, +}; + static ssize_t defrag_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { @@ -456,34 +479,19 @@ static ssize_t defrag_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { - if (sysfs_streq(buf, "always")) { - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); - set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); - } else if (sysfs_streq(buf, "defer+madvise")) { - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); - set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); - } else if (sysfs_streq(buf, "defer")) { - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); - set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); - } else if (sysfs_streq(buf, "madvise")) { - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); - set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); - } else if (sysfs_streq(buf, "never")) { - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags); - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags); - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags); - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags); - } else + int mode, m; + + mode = sysfs_match_string(defrag_mode_strings, buf); + if (mode < 0) return -EINVAL; + for (m = 0; m < ARRAY_SIZE(defrag_flags); m++) { + if (m == mode) + set_bit(defrag_flags[m], &transparent_hugepage_flags); + else + clear_bit(defrag_flags[m], &transparent_hugepage_flags); + } + return count; } static struct kobj_attribute defrag_attr = __ATTR_RW(defrag);