Date: Sat, 1 May 2010 03:41:22 +0000 (UTC) From: Kip Macy <kmacy@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r207460 - head/sys/vm Message-ID: <201005010341.o413fMhP067068@svn.freebsd.org>
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Author: kmacy Date: Sat May 1 03:41:21 2010 New Revision: 207460 URL: http://svn.freebsd.org/changeset/base/207460 Log: Update locking comment above vm_page: - re-assign page queue lock "Q" - assign page lock "P" - update several uncommented fields - observe that hold_count is now protected by the page lock "P" Modified: head/sys/vm/vm_page.h Modified: head/sys/vm/vm_page.h ============================================================================== --- head/sys/vm/vm_page.h Sat May 1 02:53:43 2010 (r207459) +++ head/sys/vm/vm_page.h Sat May 1 03:41:21 2010 (r207460) @@ -90,20 +90,21 @@ * and sundry status bits. * * Fields in this structure are locked either by the lock on the - * object that the page belongs to (O) or by the lock on the page - * queues (P). + * object that the page belongs to (O), its corresponding page lock (P), + * or by the lock on the page queues (Q). + * */ TAILQ_HEAD(pglist, vm_page); struct vm_page { - TAILQ_ENTRY(vm_page) pageq; /* queue info for FIFO queue or free list (P) */ + TAILQ_ENTRY(vm_page) pageq; /* queue info for FIFO queue or free list (Q) */ TAILQ_ENTRY(vm_page) listq; /* pages in same object (O) */ struct vm_page *left; /* splay tree link (O) */ struct vm_page *right; /* splay tree link (O) */ - vm_object_t object; /* which object am I in (O,P)*/ - vm_pindex_t pindex; /* offset into object (O,P) */ + vm_object_t object; /* which object am I in (O,Q)*/ + vm_pindex_t pindex; /* offset into object (O,Q) */ vm_paddr_t phys_addr; /* physical address of page */ struct md_page md; /* machine dependant stuff */ uint8_t queue; /* page queue index */ @@ -111,11 +112,11 @@ struct vm_page { u_short flags; /* see below */ uint8_t order; /* index of the buddy queue */ uint8_t pool; - u_short cow; /* page cow mapping count */ - u_int wire_count; /* wired down maps refs (P) */ - short hold_count; /* page hold count */ + u_short cow; /* page cow mapping count (Q) */ + u_int wire_count; /* wired down maps refs (Q) */ + short hold_count; /* page hold count (P) */ u_short oflags; /* page flags (O) */ - u_char act_count; /* page usage count */ + u_char act_count; /* page usage count (Q) */ u_char busy; /* page busy count (O) */ /* NOTE that these must support one bit per DEV_BSIZE in a page!!! */ /* so, on normal X86 kernels, they must be at least 8 bits wide */
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