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dbc984c961
The map->priv and map->erange_warned are seldom used, the first only in
tests/vmlinux-kallsyms.c, the later only when hist_entry__inc_addr_samples()
returns -ERANGE in 'perf top', which are really rare occasions, so make
them a bool bitfield.
This will open up space for other members on the first cacheline.
$ pahole -C map ~/bin/perf
struct map {
union {
struct rb_node rb_node __attribute__((__aligned__(8))); /* 0 24 */
struct list_head node; /* 0 16 */
} __attribute__((__aligned__(8))); /* 0 24 */
u64 start; /* 24 8 */
u64 end; /* 32 8 */
_Bool erange_warned:1; /* 40: 0 1 */
_Bool priv:1; /* 40: 1 1 */
/* XXX 6 bits hole, try to pack */
/* XXX 3 bytes hole, try to pack */
u32 prot; /* 44 4 */
u32 flags; /* 48 4 */
/* XXX 4 bytes hole, try to pack */
u64 pgoff; /* 56 8 */
/* --- cacheline 1 boundary (64 bytes) --- */
u64 reloc; /* 64 8 */
u32 maj; /* 72 4 */
u32 min; /* 76 4 */
u64 ino; /* 80 8 */
u64 ino_generation; /* 88 8 */
u64 (*map_ip)(struct map *, u64); /* 96 8 */
u64 (*unmap_ip)(struct map *, u64); /* 104 8 */
struct dso * dso; /* 112 8 */
refcount_t refcnt; /* 120 4 */
/* size: 128, cachelines: 2, members: 17 */
/* sum members: 116, holes: 2, sum holes: 7 */
/* sum bitfield members: 2 bits, bit holes: 1, sum bit holes: 6 bits */
/* padding: 4 */
/* forced alignments: 1 */
} __attribute__((__aligned__(8)));
$
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-g5545pcq4ff0wr17tfb1piqt@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.