New subject: 答复: [External Mail]Re: [PATCH v4] Fix: move huge compressed obj from page to zspage

Wednesday, 20 September 2023

when zspage define 'huge', crash-utility zram decompress fail.
we need to be compatible with the previous kernel,
so we can't define 'huge' directly in zspage.

Before:
crash> mod -s zram zram.ko
     MODULE       NAME                                          BASE           SIZE 
OBJECT FILE
ffffffde224db800  zram                                    ffffffde224d2000    57344 
zram.ko
crash> mod -s zsmalloc zsmalloc.ko
     MODULE       NAME                                          BASE           SIZE 
OBJECT FILE
ffffffde224c5180  zsmalloc                                ffffffde224bf000    40960 
zsmalloc.ko
crash> rd 0x13d89fb0
rd: zspage magic incorrect: b0

After:
crash> rd 0x13d89fb0
        13d89fb0:  c2b54f7170883b20                     ;.pqO..

Link: https://lkml.kernel.org/r/20211115185909.3949505-6-minchan@kernel.org

Signed-off-by: chenguanyou <chenguanyou(a)xiaomi.com&gt;
---
 defs.h     | 13 +++++++++++
 diskdump.c | 67 ++++++++++++++++++++++++++++++++++++++++++++----------
 2 files changed, 68 insertions(+), 12 deletions(-)

diff --git a/defs.h b/defs.h
index 96a7a2a..0af69cc 100644
--- a/defs.h
+++ b/defs.h
@@ -2225,6 +2225,7 @@ struct offset_table {                    /* stash of commonly-used
offsets */
    long module_memory_base;
    long module_memory_size;
    long irq_data_irq;
+   long zspage_huge;
 };

 struct size_table {         /* stash of commonly-used sizes */
@@ -7221,6 +7222,18 @@ struct zspage {
     unsigned int freeobj;
 };

+struct zspage6 {
+    struct {
+        unsigned int huge : 1;
+        unsigned int fullness : 2;
+        unsigned int class : 9;
+        unsigned int isolated : 3;
+        unsigned int magic : 8;
+    };
+    unsigned int inuse;
+    unsigned int freeobj;
+};
+
 /*
  * makedumpfile.c
  */
diff --git a/diskdump.c b/diskdump.c
index 2c284ff..02aaf1b 100644
--- a/diskdump.c
+++ b/diskdump.c
@@ -2754,6 +2754,9 @@ zram_init(void)
    if (INVALID_MEMBER(zram_table_flag))
        MEMBER_OFFSET_INIT(zram_table_flag, "zram_table_entry",
"value");
    STRUCT_SIZE_INIT(zram_table_entry, "zram_table_entry");
+    MEMBER_OFFSET_INIT(zspoll_size_class, "zs_pool", "size_class");
+    MEMBER_OFFSET_INIT(size_class_size, "size_class", "size");
+    MEMBER_OFFSET_INIT(zspage_huge, "zspage", "huge");
 }

 static unsigned char *
@@ -2761,9 +2764,11 @@ zram_object_addr(ulong pool, ulong handle, unsigned char
*zram_buf)
 {
    ulong obj, off, class, page, zspage;
    struct zspage zspage_s;
+   struct zspage6 zspage6_s;
    physaddr_t paddr;
    unsigned int obj_idx, class_idx, size;
    ulong pages[2], sizes[2];
+   ulong zs_magic;

    readmem(handle, KVADDR, &obj, sizeof(void *), "zram entry",
FAULT_ON_ERROR);
    obj >>= OBJ_TAG_BITS;
@@ -2772,11 +2777,19 @@ zram_object_addr(ulong pool, ulong handle, unsigned char
*zram_buf)

    readmem(page + OFFSET(page_private), KVADDR, &zspage,
            sizeof(void *), "page_private", FAULT_ON_ERROR);
-   readmem(zspage, KVADDR, &zspage_s, sizeof(struct zspage), "zspage",
FAULT_ON_ERROR);

-   class_idx = zspage_s.class;
-   if (zspage_s.magic != ZSPAGE_MAGIC)
-       error(FATAL, "zspage magic incorrect: %x\n", zspage_s.magic);
+   if (VALID_MEMBER(zspage_huge)) {
+       readmem(zspage, KVADDR, &zspage6_s, sizeof(struct zspage6),
"zspage6", FAULT_ON_ERROR);
+       class_idx = zspage6_s.class;
+       zs_magic = zspage6_s.magic;
+   } else {
+       readmem(zspage, KVADDR, &zspage_s, sizeof(struct zspage), "zspage",
FAULT_ON_ERROR);
+       class_idx = zspage_s.class;
+       zs_magic = zspage_s.magic;
+   }
+
+   if (zs_magic != ZSPAGE_MAGIC)
+       error(FATAL, "zspage magic incorrect: %x\n", zs_magic);

    class = pool + OFFSET(zspoll_size_class);
    class += (class_idx * sizeof(void *));
@@ -2794,8 +2807,13 @@ zram_object_addr(ulong pool, ulong handle, unsigned char
*zram_buf)
    }

    pages[0] = page;
-   readmem(page + OFFSET(page_freelist), KVADDR, &pages[1],
-           sizeof(void *), "page_freelist", FAULT_ON_ERROR);
+   if (VALID_MEMBER(page_freelist)) {
+       readmem(page + OFFSET(page_freelist), KVADDR, &pages[1],
+               sizeof(void *), "page_freelist", FAULT_ON_ERROR);
+   } else {
+       readmem(page + OFFSET(page_index), KVADDR, &pages[1],
+               sizeof(void *), "page_index", FAULT_ON_ERROR);
+   }
    sizes[0] = PAGESIZE() - off;
    sizes[1] = size - sizes[0];
    if (!is_page_ptr(pages[0], &paddr)) {
@@ -2812,9 +2830,15 @@ zram_object_addr(ulong pool, ulong handle, unsigned char
*zram_buf)
    readmem(paddr, PHYSADDR, zram_buf + sizes[0], sizes[1], "zram buffer[1]",
FAULT_ON_ERROR);

 out:
-   readmem(page, KVADDR, &obj, sizeof(void *), "page flags",
FAULT_ON_ERROR);
-   if (!(obj & (1<<10))) { //PG_OwnerPriv1 flag
-       return (zram_buf + ZS_HANDLE_SIZE);
+   if (!VALID_MEMBER(zspage_huge)) {
+       readmem(page, KVADDR, &obj, sizeof(void *), "page flags",
FAULT_ON_ERROR);
+       if (!(obj & (1<<10))) { //PG_OwnerPriv1 flag
+           return (zram_buf + ZS_HANDLE_SIZE);
+       }
+   } else {
+       if (!zspage6_s.huge) {
+           return (zram_buf + ZS_HANDLE_SIZE);
+       }
    }

    return zram_buf;
@@ -2929,6 +2953,11 @@ try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong
len, ulonglong
    unsigned char *outbuf = NULL;
    ulong zram, zram_table_entry, sector, index, entry, flags, size,
        outsize, off;
+   unsigned long *same_buf = NULL;
+   bool is_same = false;
+   ulong ZRAM_SAME_PAGEFLAG;
+   ulong ZRAM_WB_PAGEFLAG;
+   long ZRAM_LOCK_VALUE = 24;

    if (INVALID_MEMBER(zram_compressor)) {
        zram_init();
@@ -2992,11 +3021,25 @@ try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong
len, ulonglong
        sizeof(void *), "entry of table", FAULT_ON_ERROR);
    readmem(zram_table_entry + OFFSET(zram_table_flag), KVADDR, &flags,
        sizeof(void *), "zram_table_flag", FAULT_ON_ERROR);
-   if (!entry || (flags & ZRAM_FLAG_SAME_BIT)) {
-       memset(buf, entry, len);
+
+   if (!enumerator_value("ZRAM_LOCK", &ZRAM_LOCK_VALUE)
+           && THIS_KERNEL_VERSION >= LINUX(6,1,0))
+       ZRAM_LOCK_VALUE = PAGESHIFT() + 1;
+
+   ZRAM_SAME_PAGEFLAG = ZRAM_LOCK_VALUE + 1;
+   ZRAM_WB_PAGEFLAG = ZRAM_LOCK_VALUE + 2;
+
+   if (!entry || flags & (1 << ZRAM_SAME_PAGEFLAG)) {
+       same_buf = (unsigned long *)GETBUF(PAGESIZE());
+       for (int count = 0; count < PAGESIZE() / sizeof(unsigned long); count++) {
+           same_buf[count] = entry;
+       }
+       memcpy(buf, same_buf + off, PAGESIZE());
+       FREEBUF(same_buf);
        goto out;
    }
-   size = flags & (ZRAM_FLAG_SHIFT -1);
+
+   size = flags & ((1 << ZRAM_LOCK_VALUE) - 1);
    if (size == 0) {
        len = 0;
        goto out;
--
2.39.0


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[PATCH v4] Fix: move huge compressed obj from page to zspage