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comparison src/core/ngx_output_chain.c @ 3053:0d253659da12

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directio_alignment
author Igor Sysoev <igor@sysoev.ru>
date Fri, 28 Aug 2009 08:15:55 +0000
parents 6060225e9261
children 5ea5a90000d5
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3052:6060225e9261 3053:0d253659da12
14 #endif 14 #endif
15 15
16 /* 16 /*
17 * When DIRECTIO is enabled FreeBSD, Solaris, and MacOSX read directly 17 * When DIRECTIO is enabled FreeBSD, Solaris, and MacOSX read directly
18 * to an application memory from a device if parameters are aligned 18 * to an application memory from a device if parameters are aligned
19 * to device sector boundary(512 bytes). They fallback to usual read 19 * to device sector boundary (512 bytes). They fallback to usual read
20 * operation if the parameters are not aligned. 20 * operation if the parameters are not aligned.
21 * Linux allows DIRECTIO only if the parameters are aligned to a filesystem 21 * Linux allows DIRECTIO only if the parameters are aligned to a filesystem
22 * sector boundary, otherwise it returns EINVAL. The sector size is 22 * sector boundary, otherwise it returns EINVAL. The sector size is
23 * usually 512 bytes, however, on XFS it may be 4096 bytes. 23 * usually 512 bytes, however, on XFS it may be 4096 bytes.
24 */ 24 */
25 #define NGX_DIRECTIO_BLOCK 4096
26
27 25
28 #define NGX_NONE 1 26 #define NGX_NONE 1
29 27
30 28
31 static ngx_inline ngx_int_t 29 static ngx_inline ngx_int_t
335 return NGX_DECLINED; 333 return NGX_DECLINED;
336 } 334 }
337 335
338 ctx->directio = 1; 336 ctx->directio = 1;
339 337
340 size = (size_t) (in->file_pos - (in->file_pos & ~(NGX_DIRECTIO_BLOCK - 1))); 338 size = (size_t) (in->file_pos - (in->file_pos & ~(ctx->alignment - 1)));
341 339
342 if (size == 0) { 340 if (size == 0) {
343 341
344 if (bsize >= (off_t) ctx->bufs.size) { 342 if (bsize >= (off_t) ctx->bufs.size) {
345 return NGX_DECLINED; 343 return NGX_DECLINED;
346 } 344 }
347 345
348 size = (size_t) bsize; 346 size = (size_t) bsize;
349 347
350 } else { 348 } else {
351 size = NGX_DIRECTIO_BLOCK - size; 349 size = ctx->alignment - size;
352 350
353 if ((off_t) size > bsize) { 351 if ((off_t) size > bsize) {
354 size = (size_t) bsize; 352 size = (size_t) bsize;
355 } 353 }
356 } 354 }
421 /* 419 /*
422 * allocate block aligned to a disk sector size to enable 420 * allocate block aligned to a disk sector size to enable
423 * userland buffer direct usage conjunctly with directio 421 * userland buffer direct usage conjunctly with directio
424 */ 422 */
425 423
426 b->start = ngx_pmemalign(ctx->pool, size, NGX_DIRECTIO_BLOCK); 424 b->start = ngx_pmemalign(ctx->pool, size, ctx->alignment);
427 if (b->start == NULL) { 425 if (b->start == NULL) {
428 return NGX_ERROR; 426 return NGX_ERROR;
429 } 427 }
430 428
431 } else { 429 } else {