diff options
author | Mikhail Zaslonko <zaslonko@linux.ibm.com> | 2020-01-30 22:16:17 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-01-31 10:30:40 -0800 |
commit | aa5b395b69b65450e008b95ec623b4fc4b175f9f (patch) | |
tree | 83949b45e52736f277dc285576a9a6069d84a4e8 /lib/zlib_deflate/deflate.c | |
parent | f88b4265450fc879f6db8a811e33068ae168c4a4 (diff) |
lib/zlib: add s390 hardware support for kernel zlib_deflate
Patch series "S390 hardware support for kernel zlib", v3.
With IBM z15 mainframe the new DFLTCC instruction is available. It
implements deflate algorithm in hardware (Nest Acceleration Unit - NXU)
with estimated compression and decompression performance orders of
magnitude faster than the current zlib.
This patchset adds s390 hardware compression support to kernel zlib.
The code is based on the userspace zlib implementation:
https://github.com/madler/zlib/pull/410
The coding style is also preserved for future maintainability. There is
only limited set of userspace zlib functions represented in kernel.
Apart from that, all the memory allocation should be performed in
advance. Thus, the workarea structures are extended with the parameter
lists required for the DEFLATE CONVENTION CALL instruction.
Since kernel zlib itself does not support gzip headers, only Adler-32
checksum is processed (also can be produced by DFLTCC facility). Like
it was implemented for userspace, kernel zlib will compress in hardware
on level 1, and in software on all other levels. Decompression will
always happen in hardware (when enabled).
Two DFLTCC compression calls produce the same results only when they
both are made on machines of the same generation, and when the
respective buffers have the same offset relative to the start of the
page. Therefore care should be taken when using hardware compression
when reproducible results are desired. However it does always produce
the standard conform output which can be inflated anyway.
The new kernel command line parameter 'dfltcc' is introduced to
configure s390 zlib hardware support:
Format: { on | off | def_only | inf_only | always }
on: s390 zlib hardware support for compression on
level 1 and decompression (default)
off: No s390 zlib hardware support
def_only: s390 zlib hardware support for deflate
only (compression on level 1)
inf_only: s390 zlib hardware support for inflate
only (decompression)
always: Same as 'on' but ignores the selected compression
level always using hardware support (used for debugging)
The main purpose of the integration of the NXU support into the kernel
zlib is the use of hardware deflate in btrfs filesystem with on-the-fly
compression enabled. Apart from that, hardware support can also be used
during boot for decompressing the kernel or the ramdisk image
With the patch for btrfs expanding zlib buffer from 1 to 4 pages (patch
6) the following performance results have been achieved using the
ramdisk with btrfs. These are relative numbers based on throughput rate
and compression ratio for zlib level 1:
Input data Deflate rate Inflate rate Compression ratio
NXU/Software NXU/Software NXU/Software
stream of zeroes 1.46 1.02 1.00
random ASCII data 10.44 3.00 0.96
ASCII text (dickens) 6,21 3.33 0.94
binary data (vmlinux) 8,37 3.90 1.02
This means that s390 hardware deflate can provide up to 10 times faster
compression (on level 1) and up to 4 times faster decompression (refers
to all compression levels) for btrfs zlib.
Disclaimer: Performance results are based on IBM internal tests using DD
command-line utility on btrfs on a Fedora 30 based internal driver in
native LPAR on a z15 system. Results may vary based on individual
workload, configuration and software levels.
This patch (of 9):
Create zlib_dfltcc library with the s390 DEFLATE CONVERSION CALL
implementation and related compression functions. Update zlib_deflate
functions with the hooks for s390 hardware support and adjust workspace
structures with extra parameter lists required for hardware deflate.
Link: http://lkml.kernel.org/r/20200103223334.20669-2-zaslonko@linux.ibm.com
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Co-developed-by: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Eduard Shishkin <edward6@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/zlib_deflate/deflate.c')
-rw-r--r-- | lib/zlib_deflate/deflate.c | 79 |
1 files changed, 41 insertions, 38 deletions
diff --git a/lib/zlib_deflate/deflate.c b/lib/zlib_deflate/deflate.c index d20ef458f137..0d60d81a2637 100644 --- a/lib/zlib_deflate/deflate.c +++ b/lib/zlib_deflate/deflate.c @@ -52,16 +52,18 @@ #include <linux/zutil.h> #include "defutil.h" +/* architecture-specific bits */ +#ifdef CONFIG_ZLIB_DFLTCC +# include "../zlib_dfltcc/dfltcc.h" +#else +#define DEFLATE_RESET_HOOK(strm) do {} while (0) +#define DEFLATE_HOOK(strm, flush, bstate) 0 +#define DEFLATE_NEED_CHECKSUM(strm) 1 +#endif /* =========================================================================== * Function prototypes. */ -typedef enum { - need_more, /* block not completed, need more input or more output */ - block_done, /* block flush performed */ - finish_started, /* finish started, need only more output at next deflate */ - finish_done /* finish done, accept no more input or output */ -} block_state; typedef block_state (*compress_func) (deflate_state *s, int flush); /* Compression function. Returns the block state after the call. */ @@ -72,7 +74,6 @@ static block_state deflate_fast (deflate_state *s, int flush); static block_state deflate_slow (deflate_state *s, int flush); static void lm_init (deflate_state *s); static void putShortMSB (deflate_state *s, uInt b); -static void flush_pending (z_streamp strm); static int read_buf (z_streamp strm, Byte *buf, unsigned size); static uInt longest_match (deflate_state *s, IPos cur_match); @@ -98,6 +99,25 @@ static void check_match (deflate_state *s, IPos start, IPos match, * See deflate.c for comments about the MIN_MATCH+1. */ +/* Workspace to be allocated for deflate processing */ +typedef struct deflate_workspace { + /* State memory for the deflator */ + deflate_state deflate_memory; +#ifdef CONFIG_ZLIB_DFLTCC + /* State memory for s390 hardware deflate */ + struct dfltcc_state dfltcc_memory; +#endif + Byte *window_memory; + Pos *prev_memory; + Pos *head_memory; + char *overlay_memory; +} deflate_workspace; + +#ifdef CONFIG_ZLIB_DFLTCC +/* dfltcc_state must be doubleword aligned for DFLTCC call */ +static_assert(offsetof(struct deflate_workspace, dfltcc_memory) % 8 == 0); +#endif + /* Values for max_lazy_match, good_match and max_chain_length, depending on * the desired pack level (0..9). The values given below have been tuned to * exclude worst case performance for pathological files. Better values may be @@ -207,7 +227,15 @@ int zlib_deflateInit2( */ next = (char *) mem; next += sizeof(*mem); +#ifdef CONFIG_ZLIB_DFLTCC + /* + * DFLTCC requires the window to be page aligned. + * Thus, we overallocate and take the aligned portion of the buffer. + */ + mem->window_memory = (Byte *) PTR_ALIGN(next, PAGE_SIZE); +#else mem->window_memory = (Byte *) next; +#endif next += zlib_deflate_window_memsize(windowBits); mem->prev_memory = (Pos *) next; next += zlib_deflate_prev_memsize(windowBits); @@ -277,6 +305,8 @@ int zlib_deflateReset( zlib_tr_init(s); lm_init(s); + DEFLATE_RESET_HOOK(strm); + return Z_OK; } @@ -294,35 +324,6 @@ static void putShortMSB( put_byte(s, (Byte)(b & 0xff)); } -/* ========================================================================= - * Flush as much pending output as possible. All deflate() output goes - * through this function so some applications may wish to modify it - * to avoid allocating a large strm->next_out buffer and copying into it. - * (See also read_buf()). - */ -static void flush_pending( - z_streamp strm -) -{ - deflate_state *s = (deflate_state *) strm->state; - unsigned len = s->pending; - - if (len > strm->avail_out) len = strm->avail_out; - if (len == 0) return; - - if (strm->next_out != NULL) { - memcpy(strm->next_out, s->pending_out, len); - strm->next_out += len; - } - s->pending_out += len; - strm->total_out += len; - strm->avail_out -= len; - s->pending -= len; - if (s->pending == 0) { - s->pending_out = s->pending_buf; - } -} - /* ========================================================================= */ int zlib_deflate( z_streamp strm, @@ -404,7 +405,8 @@ int zlib_deflate( (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { block_state bstate; - bstate = (*(configuration_table[s->level].func))(s, flush); + bstate = DEFLATE_HOOK(strm, flush, &bstate) ? bstate : + (*(configuration_table[s->level].func))(s, flush); if (bstate == finish_started || bstate == finish_done) { s->status = FINISH_STATE; @@ -503,7 +505,8 @@ static int read_buf( strm->avail_in -= len; - if (!((deflate_state *)(strm->state))->noheader) { + if (!DEFLATE_NEED_CHECKSUM(strm)) {} + else if (!((deflate_state *)(strm->state))->noheader) { strm->adler = zlib_adler32(strm->adler, strm->next_in, len); } memcpy(buf, strm->next_in, len); |