[PATCH] file-posix: rearrange BDRVRawState fields

[PATCH] file-posix: rearrange BDRVRawState fields

[Prasad Pandit]

From: Prasad Pandit <pjp@fedoraproject.org>

Rearrange BRDVRawState structure fields to avoid memory
fragments in its object's memory and save some(~8) bytes
per object.

Signed-off-by: Prasad Pandit <pjp@fedoraproject.org>
---
 block/file-posix.c | 39 +++++++++++++++++++--------------------
 1 file changed, 19 insertions(+), 20 deletions(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index 78a8cea03b..584346ea3e 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -135,12 +135,6 @@
 #define RAW_LOCK_SHARED_BASE           200
 
 typedef struct BDRVRawState {
-    int fd;
-    bool use_lock;
-    int type;
-    int open_flags;
-    size_t buf_align;
-
     /* The current permissions. */
     uint64_t perm;
     uint64_t shared_perm;
@@ -151,29 +145,34 @@ typedef struct BDRVRawState {
     uint64_t locked_shared_perm;
 
     uint64_t aio_max_batch;
+    struct {
+        uint64_t discard_nb_ok;
+        uint64_t discard_nb_failed;
+        uint64_t discard_bytes_ok;
+    } stats;
 
+    PRManager *pr_mgr;
+    BDRVReopenState *reopen_state;
+
+    size_t buf_align;
+    int fd;
+    int type;
+    int open_flags;
     int perm_change_fd;
     int perm_change_flags;
-    BDRVReopenState *reopen_state;
+    int page_cache_inconsistent; /* errno from fdatasync failure */
 
+    bool use_lock;
+    bool has_fallocate;
+    bool needs_alignment;
+    bool force_alignment;
+    bool drop_cache;
+    bool check_cache_dropped;
     bool has_discard:1;
     bool has_write_zeroes:1;
     bool use_linux_aio:1;
     bool has_laio_fdsync:1;
     bool use_linux_io_uring:1;
-    int page_cache_inconsistent; /* errno from fdatasync failure */
-    bool has_fallocate;
-    bool needs_alignment;
-    bool force_alignment;
-    bool drop_cache;
-    bool check_cache_dropped;
-    struct {
-        uint64_t discard_nb_ok;
-        uint64_t discard_nb_failed;
-        uint64_t discard_bytes_ok;
-    } stats;
-
-    PRManager *pr_mgr;
 } BDRVRawState;
 
 typedef struct BDRVRawReopenState {
-- 
2.44.0

Re: [PATCH] file-posix: rearrange BDRVRawState fields

[Stefan Hajnoczi]

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On Thu, Mar 14, 2024 at 04:47:41PM +0530, Prasad Pandit wrote:
> From: Prasad Pandit <pjp@fedoraproject.org>
> 
> Rearrange BRDVRawState structure fields to avoid memory
> fragments in its object's memory and save some(~8) bytes
> per object.
> 
> Signed-off-by: Prasad Pandit <pjp@fedoraproject.org>
> ---
>  block/file-posix.c | 39 +++++++++++++++++++--------------------
>  1 file changed, 19 insertions(+), 20 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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