📄 memory.c
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<a name=L286 href="source/mm/memory.c#L286">286</a> <b><i> * to see if it exists, and if it is clean. If so, share it with the current</i></b><a name=L287 href="source/mm/memory.c#L287">287</a> <b><i> * task.</i></b><a name=L288 href="source/mm/memory.c#L288">288</a> <b><i> *</i></b><a name=L289 href="source/mm/memory.c#L289">289</a> <b><i> * NOTE! This assumes we have checked that p != current, and that they</i></b><a name=L290 href="source/mm/memory.c#L290">290</a> <b><i> * share the same executable.</i></b><a name=L291 href="source/mm/memory.c#L291">291</a> <b><i> */</i></b><a name=L292 href="source/mm/memory.c#L292">292</a> static int <a href="ident?i=try_to_share">try_to_share</a>(unsigned long address, struct <a href="ident?i=task_struct">task_struct</a> * p)<a name=L293 href="source/mm/memory.c#L293">293</a> {<a name=L294 href="source/mm/memory.c#L294">294</a> unsigned long from;<a name=L295 href="source/mm/memory.c#L295">295</a> unsigned long to;<a name=L296 href="source/mm/memory.c#L296">296</a> unsigned long from_page;<a name=L297 href="source/mm/memory.c#L297">297</a> unsigned long to_page;<a name=L298 href="source/mm/memory.c#L298">298</a> unsigned long phys_addr;<a name=L299 href="source/mm/memory.c#L299">299</a> <a name=L300 href="source/mm/memory.c#L300">300</a> from_page = to_page = ((address>>20) & 0xffc);<a name=L301 href="source/mm/memory.c#L301">301</a> from_page += ((p->start_code>>20) & 0xffc);<a name=L302 href="source/mm/memory.c#L302">302</a> to_page += ((<a href="ident?i=current">current</a>->start_code>>20) & 0xffc);<a name=L303 href="source/mm/memory.c#L303">303</a> <b><i>/* is there a page-directory at from? */</i></b><a name=L304 href="source/mm/memory.c#L304">304</a> from = *(unsigned long *) from_page;<a name=L305 href="source/mm/memory.c#L305">305</a> if (!(from & 1))<a name=L306 href="source/mm/memory.c#L306">306</a> return 0;<a name=L307 href="source/mm/memory.c#L307">307</a> from &= 0xfffff000;<a name=L308 href="source/mm/memory.c#L308">308</a> from_page = from + ((address>>10) & 0xffc);<a name=L309 href="source/mm/memory.c#L309">309</a> phys_addr = *(unsigned long *) from_page;<a name=L310 href="source/mm/memory.c#L310">310</a> <b><i>/* is the page clean and present? */</i></b><a name=L311 href="source/mm/memory.c#L311">311</a> if ((phys_addr & 0x41) != 0x01)<a name=L312 href="source/mm/memory.c#L312">312</a> return 0;<a name=L313 href="source/mm/memory.c#L313">313</a> phys_addr &= 0xfffff000;<a name=L314 href="source/mm/memory.c#L314">314</a> if (phys_addr >= <a href="ident?i=HIGH_MEMORY">HIGH_MEMORY</a> || phys_addr < <a href="ident?i=LOW_MEM">LOW_MEM</a>)<a name=L315 href="source/mm/memory.c#L315">315</a> return 0;<a name=L316 href="source/mm/memory.c#L316">316</a> to = *(unsigned long *) to_page;<a name=L317 href="source/mm/memory.c#L317">317</a> if (!(to & 1))<a name=L318 href="source/mm/memory.c#L318">318</a> if (to = <a href="ident?i=get_free_page">get_free_page</a>())<a name=L319 href="source/mm/memory.c#L319">319</a> *(unsigned long *) to_page = to | 7;<a name=L320 href="source/mm/memory.c#L320">320</a> else<a name=L321 href="source/mm/memory.c#L321">321</a> <a href="ident?i=oom">oom</a>();<a name=L322 href="source/mm/memory.c#L322">322</a> to &= 0xfffff000;<a name=L323 href="source/mm/memory.c#L323">323</a> to_page = to + ((address>>10) & 0xffc);<a name=L324 href="source/mm/memory.c#L324">324</a> if (1 & *(unsigned long *) to_page)<a name=L325 href="source/mm/memory.c#L325">325</a> <a href="ident?i=panic">panic</a>(<i>"try_to_share: to_page already exists"</i>);<a name=L326 href="source/mm/memory.c#L326">326</a> <b><i>/* share them: write-protect */</i></b><a name=L327 href="source/mm/memory.c#L327">327</a> *(unsigned long *) from_page &= ~2;<a name=L328 href="source/mm/memory.c#L328">328</a> *(unsigned long *) to_page = *(unsigned long *) from_page;<a name=L329 href="source/mm/memory.c#L329">329</a> <a href="ident?i=invalidate">invalidate</a>();<a name=L330 href="source/mm/memory.c#L330">330</a> phys_addr -= <a href="ident?i=LOW_MEM">LOW_MEM</a>;<a name=L331 href="source/mm/memory.c#L331">331</a> phys_addr >>= 12;<a name=L332 href="source/mm/memory.c#L332">332</a> <a href="ident?i=mem_map">mem_map</a>[phys_addr]++;<a name=L333 href="source/mm/memory.c#L333">333</a> return 1;<a name=L334 href="source/mm/memory.c#L334">334</a> }<a name=L335 href="source/mm/memory.c#L335">335</a> <a name=L336 href="source/mm/memory.c#L336">336</a> <b><i>/*</i></b><a name=L337 href="source/mm/memory.c#L337">337</a> <b><i> * share_page() tries to find a process that could share a page with</i></b><a name=L338 href="source/mm/memory.c#L338">338</a> <b><i> * the current one. Address is the address of the wanted page relative</i></b><a name=L339 href="source/mm/memory.c#L339">339</a> <b><i> * to the current data space.</i></b><a name=L340 href="source/mm/memory.c#L340">340</a> <b><i> *</i></b><a name=L341 href="source/mm/memory.c#L341">341</a> <b><i> * We first check if it is at all feasible by checking executable->i_count.</i></b><a name=L342 href="source/mm/memory.c#L342">342</a> <b><i> * It should be >1 if there are other tasks sharing this inode.</i></b><a name=L343 href="source/mm/memory.c#L343">343</a> <b><i> */</i></b><a name=L344 href="source/mm/memory.c#L344">344</a> static int <a href="ident?i=share_page">share_page</a>(unsigned long address)<a name=L345 href="source/mm/memory.c#L345">345</a> {<a name=L346 href="source/mm/memory.c#L346">346</a> struct <a href="ident?i=task_struct">task_struct</a> ** p;<a name=L347 href="source/mm/memory.c#L347">347</a> <a name=L348 href="source/mm/memory.c#L348">348</a> if (!<a href="ident?i=current">current</a>->executable)<a name=L349 href="source/mm/memory.c#L349">349</a> return 0;<a name=L350 href="source/mm/memory.c#L350">350</a> if (<a href="ident?i=current">current</a>->executable->i_count < 2)<a name=L351 href="source/mm/memory.c#L351">351</a> return 0;<a name=L352 href="source/mm/memory.c#L352">352</a> for (p = &<a href="ident?i=LAST_TASK">LAST_TASK</a> ; p > &<a href="ident?i=FIRST_TASK">FIRST_TASK</a> ; --p) {<a name=L353 href="source/mm/memory.c#L353">353</a> if (!*p)<a name=L354 href="source/mm/memory.c#L354">354</a> continue;<a name=L355 href="source/mm/memory.c#L355">355</a> if (<a href="ident?i=current">current</a> == *p)<a name=L356 href="source/mm/memory.c#L356">356</a> continue;<a name=L357 href="source/mm/memory.c#L357">357</a> if ((*p)->executable != <a href="ident?i=current">current</a>->executable)<a name=L358 href="source/mm/memory.c#L358">358</a> continue;<a name=L359 href="source/mm/memory.c#L359">359</a> if (<a href="ident?i=try_to_share">try_to_share</a>(address,*p))<a name=L360 href="source/mm/memory.c#L360">360</a> return 1;<a name=L361 href="source/mm/memory.c#L361">361</a> }<a name=L362 href="source/mm/memory.c#L362">362</a> return 0;<a name=L363 href="source/mm/memory.c#L363">363</a> }<a name=L364 href="source/mm/memory.c#L364">364</a> <a name=L365 href="source/mm/memory.c#L365">365</a> void <a href="ident?i=do_no_page">do_no_page</a>(unsigned long error_code,unsigned long address)<a name=L366 href="source/mm/memory.c#L366">366</a> {<a name=L367 href="source/mm/memory.c#L367">367</a> int nr[4];<a name=L368 href="source/mm/memory.c#L368">368</a> unsigned long tmp;<a name=L369 href="source/mm/memory.c#L369">369</a> unsigned long page;<a name=L370 href="source/mm/memory.c#L370">370</a> int block,i;<a name=L371 href="source/mm/memory.c#L371">371</a> <a name=L372 href="source/mm/memory.c#L372">372</a> address &= 0xfffff000;<a name=L373 href="source/mm/memory.c#L373">373</a> tmp = address - <a href="ident?i=current">current</a>->start_code;<a name=L374 href="source/mm/memory.c#L374">374</a> if (!<a href="ident?i=current">current</a>->executable || tmp >= <a href="ident?i=current">current</a>->end_data) {<a name=L375 href="source/mm/memory.c#L375">375</a> <a href="ident?i=get_empty_page">get_empty_page</a>(address);<a name=L376 href="source/mm/memory.c#L376">376</a> return;<a name=L377 href="source/mm/memory.c#L377">377</a> }<a name=L378 href="source/mm/memory.c#L378">378</a> if (<a href="ident?i=share_page">share_page</a>(tmp))<a name=L379 href="source/mm/memory.c#L379">379</a> return;<a name=L380 href="source/mm/memory.c#L380">380</a> if (!(page = <a href="ident?i=get_free_page">get_free_page</a>()))<a name=L381 href="source/mm/memory.c#L381">381</a> <a href="ident?i=oom">oom</a>();<a name=L382 href="source/mm/memory.c#L382">382</a> <b><i>/* remember that 1 block is used for header */</i></b><a name=L383 href="source/mm/memory.c#L383">383</a> block = 1 + tmp/<a href="ident?i=BLOCK_SIZE">BLOCK_SIZE</a>;<a name=L384 href="source/mm/memory.c#L384">384</a> for (i=0 ; i<4 ; block++,i++)<a name=L385 href="source/mm/memory.c#L385">385</a> nr[i] = <a href="ident?i=bmap">bmap</a>(<a href="ident?i=current">current</a>->executable,block);<a name=L386 href="source/mm/memory.c#L386">386</a> <a href="ident?i=bread_page">bread_page</a>(page,<a href="ident?i=current">current</a>->executable->i_dev,nr);<a name=L387 href="source/mm/memory.c#L387">387</a> i = tmp + 4096 - <a href="ident?i=current">current</a>->end_data;<a name=L388 href="source/mm/memory.c#L388">388</a> tmp = page + 4096;<a name=L389 href="source/mm/memory.c#L389">389</a> while (i-- > 0) {<a name=L390 href="source/mm/memory.c#L390">390</a> tmp--;<a name=L391 href="source/mm/memory.c#L391">391</a> *(char *)tmp = 0;<a name=L392 href="source/mm/memory.c#L392">392</a> }<a name=L393 href="source/mm/memory.c#L393">393</a> if (<a href="ident?i=put_page">put_page</a>(page,address))<a name=L394 href="source/mm/memory.c#L394">394</a> return;<a name=L395 href="source/mm/memory.c#L395">395</a> <a href="ident?i=free_page">free_page</a>(page);<a name=L396 href="source/mm/memory.c#L396">396</a> <a href="ident?i=oom">oom</a>();<a name=L397 href="source/mm/memory.c#L397">397</a> }<a name=L398 href="source/mm/memory.c#L398">398</a> <a name=L399 href="source/mm/memory.c#L399">399</a> void <a href="ident?i=mem_init">mem_init</a>(long start_mem, long end_mem)<a name=L400 href="source/mm/memory.c#L400">400</a> {<a name=L401 href="source/mm/memory.c#L401">401</a> int i;<a name=L402 href="source/mm/memory.c#L402">402</a> <a name=L403 href="source/mm/memory.c#L403">403</a> <a href="ident?i=HIGH_MEMORY">HIGH_MEMORY</a> = end_mem;<a name=L404 href="source/mm/memory.c#L404">404</a> for (i=0 ; i<<a href="ident?i=PAGING_PAGES">PAGING_PAGES</a> ; i++)<a name=L405 href="source/mm/memory.c#L405">405</a> <a href="ident?i=mem_map">mem_map</a>[i] = <a href="ident?i=USED">USED</a>;<a name=L406 href="source/mm/memory.c#L406">406</a> i = <a href="ident?i=MAP_NR">MAP_NR</a>(start_mem);<a name=L407 href="source/mm/memory.c#L407">407</a> end_mem -= start_mem;<a name=L408 href="source/mm/memory.c#L408">408</a> end_mem >>= 12;<a name=L409 href="source/mm/memory.c#L409">409</a> while (end_mem-->0)<a name=L410 href="source/mm/memory.c#L410">410</a> <a href="ident?i=mem_map">mem_map</a>[i++]=0;<a name=L411 href="source/mm/memory.c#L411">411</a> }<a name=L412 href="source/mm/memory.c#L412">412</a> <a name=L413 href="source/mm/memory.c#L413">413</a> void <a href="ident?i=calc_mem">calc_mem</a>(void)<a name=L414 href="source/mm/memory.c#L414">414</a> {<a name=L415 href="source/mm/memory.c#L415">415</a> int i,j,k,<a href="ident?i=free">free</a>=0;<a name=L416 href="source/mm/memory.c#L416">416</a> long * pg_tbl;<a name=L417 href="source/mm/memory.c#L417">417</a> <a name=L418 href="source/mm/memory.c#L418">418</a> for(i=0 ; i<<a href="ident?i=PAGING_PAGES">PAGING_PAGES</a> ; i++)<a name=L419 href="source/mm/memory.c#L419">419</a> if (!<a href="ident?i=mem_map">mem_map</a>[i]) <a href="ident?i=free">free</a>++;<a name=L420 href="source/mm/memory.c#L420">420</a> <a href="ident?i=printk">printk</a>(<i>"%d pages free (of %d)\n\r"</i>,<a href="ident?i=free">free</a>,<a href="ident?i=PAGING_PAGES">PAGING_PAGES</a>);<a name=L421 href="source/mm/memory.c#L421">421</a> for(i=2 ; i<1024 ; i++) {<a name=L422 href="source/mm/memory.c#L422">422</a> if (1&<a href="ident?i=pg_dir">pg_dir</a>[i]) {<a name=L423 href="source/mm/memory.c#L423">423</a> pg_tbl=(long *) (0xfffff000 & <a href="ident?i=pg_dir">pg_dir</a>[i]);<a name=L424 href="source/mm/memory.c#L424">424</a> for(j=k=0 ; j<1024 ; j++)<a name=L425 href="source/mm/memory.c#L425">425</a> if (pg_tbl[j]&1)<a name=L426 href="source/mm/memory.c#L426">426</a> k++;<a name=L427 href="source/mm/memory.c#L427">427</a> <a href="ident?i=printk">printk</a>(<i>"Pg-dir[%d] uses %d pages\n"</i>,i,k);<a name=L428 href="source/mm/memory.c#L428">428</a> }<a name=L429 href="source/mm/memory.c#L429">429</a> }<a name=L430 href="source/mm/memory.c#L430">430</a> }<a name=L431 href="source/mm/memory.c#L431">431</a> </pre><hr><div align=center> [<b><i>源代码浏览</i></b>] [<a href="diff/mm/memory.c">区别标定</a>] [<a href="ident">标识符搜索</a>] [<a href="search">文本搜索</a>] [<a href="find">文件搜索</a>] </div><hr>本网页由 <a href="http:blurb.html">LXR引擎</a> 自动生成.<br></html>⌨️ 快捷键说明
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